From 35534c869c62f59203c1822769bbef14e894a9e9 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 19 Dec 2016 17:43:19 -0500 Subject: radix tree: constify some pointers If we're just getting the value of a tag, or looking up an entry, we won't modify the radix tree, so we can declare these functions as taking a const pointer. Mostly for documentation purposes, though it might help code generation. Signed-off-by: Matthew Wilcox --- lib/radix-tree.c | 57 ++++++++++++++++++++++++++++++-------------------------- 1 file changed, 31 insertions(+), 26 deletions(-) (limited to 'lib') diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 84812a9fb16f..6f86fbac0e36 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -83,26 +83,28 @@ static inline void *node_to_entry(void *ptr) #ifdef CONFIG_RADIX_TREE_MULTIORDER /* Sibling slots point directly to another slot in the same node */ -static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node) +static inline +bool is_sibling_entry(const struct radix_tree_node *parent, void *node) { void **ptr = node; return (parent->slots <= ptr) && (ptr < parent->slots + RADIX_TREE_MAP_SIZE); } #else -static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node) +static inline +bool is_sibling_entry(const struct radix_tree_node *parent, void *node) { return false; } #endif -static inline unsigned long get_slot_offset(struct radix_tree_node *parent, - void **slot) +static inline +unsigned long get_slot_offset(const struct radix_tree_node *parent, void **slot) { return slot - parent->slots; } -static unsigned int radix_tree_descend(struct radix_tree_node *parent, +static unsigned int radix_tree_descend(const struct radix_tree_node *parent, struct radix_tree_node **nodep, unsigned long index) { unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK; @@ -122,7 +124,7 @@ static unsigned int radix_tree_descend(struct radix_tree_node *parent, return offset; } -static inline gfp_t root_gfp_mask(struct radix_tree_root *root) +static inline gfp_t root_gfp_mask(const struct radix_tree_root *root) { return root->gfp_mask & __GFP_BITS_MASK; } @@ -139,13 +141,13 @@ static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, __clear_bit(offset, node->tags[tag]); } -static inline int tag_get(struct radix_tree_node *node, unsigned int tag, +static inline int tag_get(const struct radix_tree_node *node, unsigned int tag, int offset) { return test_bit(offset, node->tags[tag]); } -static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) +static inline void root_tag_set(struct radix_tree_root *root, unsigned tag) { root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); } @@ -160,12 +162,12 @@ static inline void root_tag_clear_all(struct radix_tree_root *root) root->gfp_mask &= __GFP_BITS_MASK; } -static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) +static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag) { return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); } -static inline unsigned root_tags_get(struct radix_tree_root *root) +static inline unsigned root_tags_get(const struct radix_tree_root *root) { return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT; } @@ -174,7 +176,8 @@ static inline unsigned root_tags_get(struct radix_tree_root *root) * Returns 1 if any slot in the node has this tag set. * Otherwise returns 0. */ -static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) +static inline int any_tag_set(const struct radix_tree_node *node, + unsigned int tag) { unsigned idx; for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { @@ -232,7 +235,7 @@ static inline unsigned long shift_maxindex(unsigned int shift) return (RADIX_TREE_MAP_SIZE << shift) - 1; } -static inline unsigned long node_maxindex(struct radix_tree_node *node) +static inline unsigned long node_maxindex(const struct radix_tree_node *node) { return shift_maxindex(node->shift); } @@ -510,7 +513,7 @@ int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order) return __radix_tree_preload(gfp_mask, nr_nodes); } -static unsigned radix_tree_load_root(struct radix_tree_root *root, +static unsigned radix_tree_load_root(const struct radix_tree_root *root, struct radix_tree_node **nodep, unsigned long *maxindex) { struct radix_tree_node *node = rcu_dereference_raw(root->rnode); @@ -908,8 +911,9 @@ EXPORT_SYMBOL(__radix_tree_insert); * allocated and @root->rnode is used as a direct slot instead of * pointing to a node, in which case *@nodep will be NULL. */ -void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, - struct radix_tree_node **nodep, void ***slotp) +void *__radix_tree_lookup(const struct radix_tree_root *root, + unsigned long index, struct radix_tree_node **nodep, + void ***slotp) { struct radix_tree_node *node, *parent; unsigned long maxindex; @@ -952,7 +956,8 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, * exclusive from other writers. Any dereference of the slot must be done * using radix_tree_deref_slot. */ -void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) +void **radix_tree_lookup_slot(const struct radix_tree_root *root, + unsigned long index) { void **slot; @@ -974,7 +979,7 @@ EXPORT_SYMBOL(radix_tree_lookup_slot); * them safely). No RCU barriers are required to access or modify the * returned item, however. */ -void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) +void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index) { return __radix_tree_lookup(root, index, NULL, NULL); } @@ -1404,7 +1409,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear); * the RCU lock is held, unless tag modification and node deletion are excluded * from concurrency. */ -int radix_tree_tag_get(struct radix_tree_root *root, +int radix_tree_tag_get(const struct radix_tree_root *root, unsigned long index, unsigned int tag) { struct radix_tree_node *node, *parent; @@ -1568,7 +1573,7 @@ EXPORT_SYMBOL(radix_tree_iter_resume); * @flags: RADIX_TREE_ITER_* flags and tag index * Returns: pointer to chunk first slot, or NULL if iteration is over */ -void **radix_tree_next_chunk(struct radix_tree_root *root, +void **radix_tree_next_chunk(const struct radix_tree_root *root, struct radix_tree_iter *iter, unsigned flags) { unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; @@ -1679,7 +1684,7 @@ EXPORT_SYMBOL(radix_tree_next_chunk); * stored in 'results'. */ unsigned int -radix_tree_gang_lookup(struct radix_tree_root *root, void **results, +radix_tree_gang_lookup(const struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items) { struct radix_tree_iter iter; @@ -1724,7 +1729,7 @@ EXPORT_SYMBOL(radix_tree_gang_lookup); * protection, radix_tree_deref_slot may fail requiring a retry. */ unsigned int -radix_tree_gang_lookup_slot(struct radix_tree_root *root, +radix_tree_gang_lookup_slot(const struct radix_tree_root *root, void ***results, unsigned long *indices, unsigned long first_index, unsigned int max_items) { @@ -1761,7 +1766,7 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_slot); * returns the number of items which were placed at *@results. */ unsigned int -radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, +radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items, unsigned int tag) { @@ -1802,9 +1807,9 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_tag); * returns the number of slots which were placed at *@results. */ unsigned int -radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, - unsigned long first_index, unsigned int max_items, - unsigned int tag) +radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root, + void ***results, unsigned long first_index, + unsigned int max_items, unsigned int tag) { struct radix_tree_iter iter; void **slot; @@ -1921,7 +1926,7 @@ void radix_tree_clear_tags(struct radix_tree_root *root, * @root: radix tree root * @tag: tag to test */ -int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) +int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag) { return root_tag_get(root, tag); } -- cgit v1.2.3 From 30b888ba950d9f77326b50a4aa2d7d99557d5718 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Sat, 28 Jan 2017 09:55:20 -0500 Subject: radix-tree: Add radix_tree_iter_tag_clear() The counterpart to radix_tree_iter_tag_set(), used by the IDR code Signed-off-by: Matthew Wilcox Reviewed-by: Rehas Sachdeva --- include/linux/radix-tree.h | 4 ++- lib/radix-tree.c | 68 +++++++++++++++++++++++++++------------------- 2 files changed, 43 insertions(+), 29 deletions(-) (limited to 'lib') diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 32683c7c2e0d..8bf4ef448ce1 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -332,7 +332,9 @@ void *radix_tree_tag_clear(struct radix_tree_root *root, unsigned long index, unsigned int tag); int radix_tree_tag_get(const struct radix_tree_root *, unsigned long index, unsigned int tag); -void radix_tree_iter_tag_set(struct radix_tree_root *root, +void radix_tree_iter_tag_set(struct radix_tree_root *, + const struct radix_tree_iter *iter, unsigned int tag); +void radix_tree_iter_tag_clear(struct radix_tree_root *, const struct radix_tree_iter *iter, unsigned int tag); unsigned int radix_tree_gang_lookup_tag(const struct radix_tree_root *, void **results, diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 6f86fbac0e36..40f3091c5a6b 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -1266,6 +1266,22 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, } #endif +static void node_tag_set(struct radix_tree_root *root, + struct radix_tree_node *node, + unsigned int tag, unsigned int offset) +{ + while (node) { + if (tag_get(node, tag, offset)) + return; + tag_set(node, tag, offset); + offset = node->offset; + node = node->parent; + } + + if (!root_tag_get(root, tag)) + root_tag_set(root, tag); +} + /** * radix_tree_tag_set - set a tag on a radix tree node * @root: radix tree root @@ -1307,6 +1323,18 @@ void *radix_tree_tag_set(struct radix_tree_root *root, } EXPORT_SYMBOL(radix_tree_tag_set); +/** + * radix_tree_iter_tag_set - set a tag on the current iterator entry + * @root: radix tree root + * @iter: iterator state + * @tag: tag to set + */ +void radix_tree_iter_tag_set(struct radix_tree_root *root, + const struct radix_tree_iter *iter, unsigned int tag) +{ + node_tag_set(root, iter->node, tag, iter_offset(iter)); +} + static void node_tag_clear(struct radix_tree_root *root, struct radix_tree_node *node, unsigned int tag, unsigned int offset) @@ -1327,34 +1355,6 @@ static void node_tag_clear(struct radix_tree_root *root, root_tag_clear(root, tag); } -static void node_tag_set(struct radix_tree_root *root, - struct radix_tree_node *node, - unsigned int tag, unsigned int offset) -{ - while (node) { - if (tag_get(node, tag, offset)) - return; - tag_set(node, tag, offset); - offset = node->offset; - node = node->parent; - } - - if (!root_tag_get(root, tag)) - root_tag_set(root, tag); -} - -/** - * radix_tree_iter_tag_set - set a tag on the current iterator entry - * @root: radix tree root - * @iter: iterator state - * @tag: tag to set - */ -void radix_tree_iter_tag_set(struct radix_tree_root *root, - const struct radix_tree_iter *iter, unsigned int tag) -{ - node_tag_set(root, iter->node, tag, iter_offset(iter)); -} - /** * radix_tree_tag_clear - clear a tag on a radix tree node * @root: radix tree root @@ -1394,6 +1394,18 @@ void *radix_tree_tag_clear(struct radix_tree_root *root, } EXPORT_SYMBOL(radix_tree_tag_clear); +/** + * radix_tree_iter_tag_clear - clear a tag on the current iterator entry + * @root: radix tree root + * @iter: iterator state + * @tag: tag to clear + */ +void radix_tree_iter_tag_clear(struct radix_tree_root *root, + const struct radix_tree_iter *iter, unsigned int tag) +{ + node_tag_clear(root, iter->node, tag, iter_offset(iter)); +} + /** * radix_tree_tag_get - get a tag on a radix tree node * @root: radix tree root -- cgit v1.2.3 From 0ac398ef391b53122976325ab6953456ce8e8310 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Sat, 28 Jan 2017 09:56:22 -0500 Subject: radix-tree: Add radix_tree_iter_delete Factor the deletion code out into __radix_tree_delete() and provide a nice iterator-based wrapper around it. If we free the node, advance the iterator to avoid reading from freed memory. Signed-off-by: Matthew Wilcox --- include/linux/radix-tree.h | 2 + lib/radix-tree.c | 91 ++++++++++++++++++++++++++++++---------------- 2 files changed, 62 insertions(+), 31 deletions(-) (limited to 'lib') diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 8bf4ef448ce1..05f715cb8062 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -311,6 +311,8 @@ void __radix_tree_delete_node(struct radix_tree_root *root, struct radix_tree_node *node, radix_tree_update_node_t update_node, void *private); +void radix_tree_iter_delete(struct radix_tree_root *, + struct radix_tree_iter *iter, void **slot); void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *); void *radix_tree_delete(struct radix_tree_root *, unsigned long); void radix_tree_clear_tags(struct radix_tree_root *root, diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 40f3091c5a6b..7bf7d4e60e43 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -581,10 +581,12 @@ out: * radix_tree_shrink - shrink radix tree to minimum height * @root radix tree root */ -static inline void radix_tree_shrink(struct radix_tree_root *root, +static inline bool radix_tree_shrink(struct radix_tree_root *root, radix_tree_update_node_t update_node, void *private) { + bool shrunk = false; + for (;;) { struct radix_tree_node *node = root->rnode; struct radix_tree_node *child; @@ -645,20 +647,26 @@ static inline void radix_tree_shrink(struct radix_tree_root *root, WARN_ON_ONCE(!list_empty(&node->private_list)); radix_tree_node_free(node); + shrunk = true; } + + return shrunk; } -static void delete_node(struct radix_tree_root *root, +static bool delete_node(struct radix_tree_root *root, struct radix_tree_node *node, radix_tree_update_node_t update_node, void *private) { + bool deleted = false; + do { struct radix_tree_node *parent; if (node->count) { if (node == entry_to_node(root->rnode)) - radix_tree_shrink(root, update_node, private); - return; + deleted |= radix_tree_shrink(root, update_node, + private); + return deleted; } parent = node->parent; @@ -672,9 +680,12 @@ static void delete_node(struct radix_tree_root *root, WARN_ON_ONCE(!list_empty(&node->private_list)); radix_tree_node_free(node); + deleted = true; node = parent; } while (node); + + return deleted; } /** @@ -1859,25 +1870,55 @@ void __radix_tree_delete_node(struct radix_tree_root *root, delete_node(root, node, update_node, private); } +static bool __radix_tree_delete(struct radix_tree_root *root, + struct radix_tree_node *node, void **slot) +{ + unsigned offset = get_slot_offset(node, slot); + int tag; + + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) + node_tag_clear(root, node, tag, offset); + + replace_slot(root, node, slot, NULL, true); + return node && delete_node(root, node, NULL, NULL); +} + /** - * radix_tree_delete_item - delete an item from a radix tree - * @root: radix tree root - * @index: index key - * @item: expected item + * radix_tree_iter_delete - delete the entry at this iterator position + * @root: radix tree root + * @iter: iterator state + * @slot: pointer to slot * - * Remove @item at @index from the radix tree rooted at @root. + * Delete the entry at the position currently pointed to by the iterator. + * This may result in the current node being freed; if it is, the iterator + * is advanced so that it will not reference the freed memory. This + * function may be called without any locking if there are no other threads + * which can access this tree. + */ +void radix_tree_iter_delete(struct radix_tree_root *root, + struct radix_tree_iter *iter, void **slot) +{ + if (__radix_tree_delete(root, iter->node, slot)) + iter->index = iter->next_index; +} + +/** + * radix_tree_delete_item - delete an item from a radix tree + * @root: radix tree root + * @index: index key + * @item: expected item + * + * Remove @item at @index from the radix tree rooted at @root. * - * Returns the address of the deleted item, or NULL if it was not present - * or the entry at the given @index was not @item. + * Return: the deleted entry, or %NULL if it was not present + * or the entry at the given @index was not @item. */ void *radix_tree_delete_item(struct radix_tree_root *root, unsigned long index, void *item) { struct radix_tree_node *node; - unsigned int offset; void **slot; void *entry; - int tag; entry = __radix_tree_lookup(root, index, &node, &slot); if (!entry) @@ -1886,32 +1927,20 @@ void *radix_tree_delete_item(struct radix_tree_root *root, if (item && entry != item) return NULL; - if (!node) { - root_tag_clear_all(root); - root->rnode = NULL; - return entry; - } - - offset = get_slot_offset(node, slot); - - /* Clear all tags associated with the item to be deleted. */ - for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) - node_tag_clear(root, node, tag, offset); - - __radix_tree_replace(root, node, slot, NULL, NULL, NULL); + __radix_tree_delete(root, node, slot); return entry; } EXPORT_SYMBOL(radix_tree_delete_item); /** - * radix_tree_delete - delete an item from a radix tree - * @root: radix tree root - * @index: index key + * radix_tree_delete - delete an entry from a radix tree + * @root: radix tree root + * @index: index key * - * Remove the item at @index from the radix tree rooted at @root. + * Remove the entry at @index from the radix tree rooted at @root. * - * Returns the address of the deleted item, or NULL if it was not present. + * Return: The deleted entry, or %NULL if it was not present. */ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) { -- cgit v1.2.3 From 0a835c4f090af2c76fc2932c539c3b32fd21fbbb Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 20 Dec 2016 10:27:56 -0500 Subject: Reimplement IDR and IDA using the radix tree The IDR is very similar to the radix tree. It has some functionality that the radix tree did not have (alloc next free, cyclic allocation, a callback-based for_each, destroy tree), which is readily implementable on top of the radix tree. A few small changes were needed in order to use a tag to represent nodes with free space below them. More extensive changes were needed to support storing NULL as a valid entry in an IDR. Plain radix trees still interpret NULL as a not-present entry. The IDA is reimplemented as a client of the newly enhanced radix tree. As in the current implementation, it uses a bitmap at the last level of the tree. Signed-off-by: Matthew Wilcox Signed-off-by: Matthew Wilcox Tested-by: Kirill A. Shutemov Cc: Konstantin Khlebnikov Cc: Ross Zwisler Cc: Tejun Heo Signed-off-by: Andrew Morton --- include/linux/idr.h | 145 ++-- include/linux/radix-tree.h | 49 +- init/main.c | 3 +- lib/idr.c | 1178 ++++++------------------------- lib/radix-tree.c | 375 +++++++--- tools/testing/radix-tree/.gitignore | 1 + tools/testing/radix-tree/Makefile | 10 +- tools/testing/radix-tree/idr-test.c | 342 +++++++++ tools/testing/radix-tree/linux/gfp.h | 8 +- tools/testing/radix-tree/linux/idr.h | 1 + tools/testing/radix-tree/linux/kernel.h | 1 + tools/testing/radix-tree/main.c | 6 + tools/testing/radix-tree/test.h | 2 + 13 files changed, 995 insertions(+), 1126 deletions(-) create mode 100644 tools/testing/radix-tree/idr-test.c create mode 100644 tools/testing/radix-tree/linux/idr.h (limited to 'lib') diff --git a/include/linux/idr.h b/include/linux/idr.h index 3c01b89aed67..f58c0a3addc3 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -12,47 +12,28 @@ #ifndef __IDR_H__ #define __IDR_H__ -#include -#include -#include -#include +#include +#include + +struct idr { + struct radix_tree_root idr_rt; + unsigned int idr_next; +}; /* - * Using 6 bits at each layer allows us to allocate 7 layers out of each page. - * 8 bits only gave us 3 layers out of every pair of pages, which is less - * efficient except for trees with a largest element between 192-255 inclusive. + * The IDR API does not expose the tagging functionality of the radix tree + * to users. Use tag 0 to track whether a node has free space below it. */ -#define IDR_BITS 6 -#define IDR_SIZE (1 << IDR_BITS) -#define IDR_MASK ((1 << IDR_BITS)-1) - -struct idr_layer { - int prefix; /* the ID prefix of this idr_layer */ - int layer; /* distance from leaf */ - struct idr_layer __rcu *ary[1<cur); + return READ_ONCE(idr->idr_next); } /** @@ -77,7 +58,7 @@ static inline unsigned int idr_get_cursor(struct idr *idr) */ static inline void idr_set_cursor(struct idr *idr, unsigned int val) { - WRITE_ONCE(idr->cur, val); + WRITE_ONCE(idr->idr_next, val); } /** @@ -97,22 +78,31 @@ static inline void idr_set_cursor(struct idr *idr, unsigned int val) * period). */ -/* - * This is what we export. - */ - -void *idr_find_slowpath(struct idr *idp, int id); void idr_preload(gfp_t gfp_mask); -int idr_alloc(struct idr *idp, void *ptr, int start, int end, gfp_t gfp_mask); -int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask); -int idr_for_each(struct idr *idp, +int idr_alloc(struct idr *, void *entry, int start, int end, gfp_t); +int idr_alloc_cyclic(struct idr *, void *entry, int start, int end, gfp_t); +int idr_for_each(const struct idr *, int (*fn)(int id, void *p, void *data), void *data); -void *idr_get_next(struct idr *idp, int *nextid); -void *idr_replace(struct idr *idp, void *ptr, int id); -void idr_remove(struct idr *idp, int id); -void idr_destroy(struct idr *idp); -void idr_init(struct idr *idp); -bool idr_is_empty(struct idr *idp); +void *idr_get_next(struct idr *, int *nextid); +void *idr_replace(struct idr *, void *, int id); +void idr_destroy(struct idr *); + +static inline void idr_remove(struct idr *idr, int id) +{ + radix_tree_delete(&idr->idr_rt, id); +} + +static inline void idr_init(struct idr *idr) +{ + INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER); + idr->idr_next = 0; +} + +static inline bool idr_is_empty(const struct idr *idr) +{ + return radix_tree_empty(&idr->idr_rt) && + radix_tree_tagged(&idr->idr_rt, IDR_FREE); +} /** * idr_preload_end - end preload section started with idr_preload() @@ -137,19 +127,14 @@ static inline void idr_preload_end(void) * This function can be called under rcu_read_lock(), given that the leaf * pointers lifetimes are correctly managed. */ -static inline void *idr_find(struct idr *idr, int id) +static inline void *idr_find(const struct idr *idr, int id) { - struct idr_layer *hint = rcu_dereference_raw(idr->hint); - - if (hint && (id & ~IDR_MASK) == hint->prefix) - return rcu_dereference_raw(hint->ary[id & IDR_MASK]); - - return idr_find_slowpath(idr, id); + return radix_tree_lookup(&idr->idr_rt, id); } /** * idr_for_each_entry - iterate over an idr's elements of a given type - * @idp: idr handle + * @idr: idr handle * @entry: the type * to use as cursor * @id: id entry's key * @@ -157,57 +142,60 @@ static inline void *idr_find(struct idr *idr, int id) * after normal terminatinon @entry is left with the value NULL. This * is convenient for a "not found" value. */ -#define idr_for_each_entry(idp, entry, id) \ - for (id = 0; ((entry) = idr_get_next(idp, &(id))) != NULL; ++id) +#define idr_for_each_entry(idr, entry, id) \ + for (id = 0; ((entry) = idr_get_next(idr, &(id))) != NULL; ++id) /** - * idr_for_each_entry - continue iteration over an idr's elements of a given type - * @idp: idr handle + * idr_for_each_entry_continue - continue iteration over an idr's elements of a given type + * @idr: idr handle * @entry: the type * to use as cursor * @id: id entry's key * * Continue to iterate over list of given type, continuing after * the current position. */ -#define idr_for_each_entry_continue(idp, entry, id) \ - for ((entry) = idr_get_next((idp), &(id)); \ +#define idr_for_each_entry_continue(idr, entry, id) \ + for ((entry) = idr_get_next((idr), &(id)); \ entry; \ - ++id, (entry) = idr_get_next((idp), &(id))) + ++id, (entry) = idr_get_next((idr), &(id))) /* * IDA - IDR based id allocator, use when translation from id to * pointer isn't necessary. - * - * IDA_BITMAP_LONGS is calculated to be one less to accommodate - * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes. */ #define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */ -#define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long) - 1) +#define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long)) #define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8) struct ida_bitmap { - long nr_busy; unsigned long bitmap[IDA_BITMAP_LONGS]; }; struct ida { - struct idr idr; + struct radix_tree_root ida_rt; struct ida_bitmap *free_bitmap; }; -#define IDA_INIT(name) { .idr = IDR_INIT((name).idr), .free_bitmap = NULL, } -#define DEFINE_IDA(name) struct ida name = IDA_INIT(name) +#define IDA_INIT { \ + .ida_rt = RADIX_TREE_INIT(IDR_RT_MARKER | GFP_NOWAIT), \ +} +#define DEFINE_IDA(name) struct ida name = IDA_INIT int ida_pre_get(struct ida *ida, gfp_t gfp_mask); int ida_get_new_above(struct ida *ida, int starting_id, int *p_id); void ida_remove(struct ida *ida, int id); void ida_destroy(struct ida *ida); -void ida_init(struct ida *ida); int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, gfp_t gfp_mask); void ida_simple_remove(struct ida *ida, unsigned int id); +static inline void ida_init(struct ida *ida) +{ + INIT_RADIX_TREE(&ida->ida_rt, IDR_RT_MARKER | GFP_NOWAIT); + ida->free_bitmap = NULL; +} + /** * ida_get_new - allocate new ID * @ida: idr handle @@ -220,11 +208,8 @@ static inline int ida_get_new(struct ida *ida, int *p_id) return ida_get_new_above(ida, 0, p_id); } -static inline bool ida_is_empty(struct ida *ida) +static inline bool ida_is_empty(const struct ida *ida) { - return idr_is_empty(&ida->idr); + return radix_tree_empty(&ida->ida_rt); } - -void __init idr_init_cache(void); - #endif /* __IDR_H__ */ diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 05f715cb8062..2ba0c1f46c84 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -105,7 +105,10 @@ struct radix_tree_node { unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; }; -/* root tags are stored in gfp_mask, shifted by __GFP_BITS_SHIFT */ +/* The top bits of gfp_mask are used to store the root tags and the IDR flag */ +#define ROOT_IS_IDR ((__force gfp_t)(1 << __GFP_BITS_SHIFT)) +#define ROOT_TAG_SHIFT (__GFP_BITS_SHIFT + 1) + struct radix_tree_root { gfp_t gfp_mask; struct radix_tree_node __rcu *rnode; @@ -358,10 +361,14 @@ int radix_tree_split(struct radix_tree_root *, unsigned long index, unsigned new_order); int radix_tree_join(struct radix_tree_root *, unsigned long index, unsigned new_order, void *); +void **idr_get_free(struct radix_tree_root *, struct radix_tree_iter *, + gfp_t, int end); -#define RADIX_TREE_ITER_TAG_MASK 0x00FF /* tag index in lower byte */ -#define RADIX_TREE_ITER_TAGGED 0x0100 /* lookup tagged slots */ -#define RADIX_TREE_ITER_CONTIG 0x0200 /* stop at first hole */ +enum { + RADIX_TREE_ITER_TAG_MASK = 0x0f, /* tag index in lower nybble */ + RADIX_TREE_ITER_TAGGED = 0x10, /* lookup tagged slots */ + RADIX_TREE_ITER_CONTIG = 0x20, /* stop at first hole */ +}; /** * radix_tree_iter_init - initialize radix tree iterator @@ -402,6 +409,40 @@ radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) void **radix_tree_next_chunk(const struct radix_tree_root *, struct radix_tree_iter *iter, unsigned flags); +/** + * radix_tree_iter_lookup - look up an index in the radix tree + * @root: radix tree root + * @iter: iterator state + * @index: key to look up + * + * If @index is present in the radix tree, this function returns the slot + * containing it and updates @iter to describe the entry. If @index is not + * present, it returns NULL. + */ +static inline void **radix_tree_iter_lookup(const struct radix_tree_root *root, + struct radix_tree_iter *iter, unsigned long index) +{ + radix_tree_iter_init(iter, index); + return radix_tree_next_chunk(root, iter, RADIX_TREE_ITER_CONTIG); +} + +/** + * radix_tree_iter_find - find a present entry + * @root: radix tree root + * @iter: iterator state + * @index: start location + * + * This function returns the slot containing the entry with the lowest index + * which is at least @index. If @index is larger than any present entry, this + * function returns NULL. The @iter is updated to describe the entry found. + */ +static inline void **radix_tree_iter_find(const struct radix_tree_root *root, + struct radix_tree_iter *iter, unsigned long index) +{ + radix_tree_iter_init(iter, index); + return radix_tree_next_chunk(root, iter, 0); +} + /** * radix_tree_iter_retry - retry this chunk of the iteration * @iter: iterator state diff --git a/init/main.c b/init/main.c index b0c9d6facef9..a65e3aad31bc 100644 --- a/init/main.c +++ b/init/main.c @@ -553,7 +553,7 @@ asmlinkage __visible void __init start_kernel(void) if (WARN(!irqs_disabled(), "Interrupts were enabled *very* early, fixing it\n")) local_irq_disable(); - idr_init_cache(); + radix_tree_init(); /* * Allow workqueue creation and work item queueing/cancelling @@ -568,7 +568,6 @@ asmlinkage __visible void __init start_kernel(void) trace_init(); context_tracking_init(); - radix_tree_init(); /* init some links before init_ISA_irqs() */ early_irq_init(); init_IRQ(); diff --git a/lib/idr.c b/lib/idr.c index 52d2979a05e8..b87056e2cc4c 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -1,1068 +1,369 @@ -/* - * 2002-10-18 written by Jim Houston jim.houston@ccur.com - * Copyright (C) 2002 by Concurrent Computer Corporation - * Distributed under the GNU GPL license version 2. - * - * Modified by George Anzinger to reuse immediately and to use - * find bit instructions. Also removed _irq on spinlocks. - * - * Modified by Nadia Derbey to make it RCU safe. - * - * Small id to pointer translation service. - * - * It uses a radix tree like structure as a sparse array indexed - * by the id to obtain the pointer. The bitmap makes allocating - * a new id quick. - * - * You call it to allocate an id (an int) an associate with that id a - * pointer or what ever, we treat it as a (void *). You can pass this - * id to a user for him to pass back at a later time. You then pass - * that id to this code and it returns your pointer. - */ - -#ifndef TEST // to test in user space... -#include -#include +#include #include -#endif -#include -#include #include +#include #include -#include -#define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) -#define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) - -/* Leave the possibility of an incomplete final layer */ -#define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) - -/* Number of id_layer structs to leave in free list */ -#define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) - -static struct kmem_cache *idr_layer_cache; -static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head); -static DEFINE_PER_CPU(int, idr_preload_cnt); static DEFINE_SPINLOCK(simple_ida_lock); -/* the maximum ID which can be allocated given idr->layers */ -static int idr_max(int layers) -{ - int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); - - return (1 << bits) - 1; -} - -/* - * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is - * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and - * so on. - */ -static int idr_layer_prefix_mask(int layer) -{ - return ~idr_max(layer + 1); -} - -static struct idr_layer *get_from_free_list(struct idr *idp) -{ - struct idr_layer *p; - unsigned long flags; - - spin_lock_irqsave(&idp->lock, flags); - if ((p = idp->id_free)) { - idp->id_free = p->ary[0]; - idp->id_free_cnt--; - p->ary[0] = NULL; - } - spin_unlock_irqrestore(&idp->lock, flags); - return(p); -} - -/** - * idr_layer_alloc - allocate a new idr_layer - * @gfp_mask: allocation mask - * @layer_idr: optional idr to allocate from - * - * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch - * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch - * an idr_layer from @idr->id_free. - * - * @layer_idr is to maintain backward compatibility with the old alloc - * interface - idr_pre_get() and idr_get_new*() - and will be removed - * together with per-pool preload buffer. - */ -static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) -{ - struct idr_layer *new; - - /* this is the old path, bypass to get_from_free_list() */ - if (layer_idr) - return get_from_free_list(layer_idr); - - /* - * Try to allocate directly from kmem_cache. We want to try this - * before preload buffer; otherwise, non-preloading idr_alloc() - * users will end up taking advantage of preloading ones. As the - * following is allowed to fail for preloaded cases, suppress - * warning this time. - */ - new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN); - if (new) - return new; - - /* - * Try to fetch one from the per-cpu preload buffer if in process - * context. See idr_preload() for details. - */ - if (!in_interrupt()) { - preempt_disable(); - new = __this_cpu_read(idr_preload_head); - if (new) { - __this_cpu_write(idr_preload_head, new->ary[0]); - __this_cpu_dec(idr_preload_cnt); - new->ary[0] = NULL; - } - preempt_enable(); - if (new) - return new; - } - - /* - * Both failed. Try kmem_cache again w/o adding __GFP_NOWARN so - * that memory allocation failure warning is printed as intended. - */ - return kmem_cache_zalloc(idr_layer_cache, gfp_mask); -} - -static void idr_layer_rcu_free(struct rcu_head *head) -{ - struct idr_layer *layer; - - layer = container_of(head, struct idr_layer, rcu_head); - kmem_cache_free(idr_layer_cache, layer); -} - -static inline void free_layer(struct idr *idr, struct idr_layer *p) -{ - if (idr->hint == p) - RCU_INIT_POINTER(idr->hint, NULL); - call_rcu(&p->rcu_head, idr_layer_rcu_free); -} - -/* only called when idp->lock is held */ -static void __move_to_free_list(struct idr *idp, struct idr_layer *p) -{ - p->ary[0] = idp->id_free; - idp->id_free = p; - idp->id_free_cnt++; -} - -static void move_to_free_list(struct idr *idp, struct idr_layer *p) -{ - unsigned long flags; - - /* - * Depends on the return element being zeroed. - */ - spin_lock_irqsave(&idp->lock, flags); - __move_to_free_list(idp, p); - spin_unlock_irqrestore(&idp->lock, flags); -} - -static void idr_mark_full(struct idr_layer **pa, int id) -{ - struct idr_layer *p = pa[0]; - int l = 0; - - __set_bit(id & IDR_MASK, p->bitmap); - /* - * If this layer is full mark the bit in the layer above to - * show that this part of the radix tree is full. This may - * complete the layer above and require walking up the radix - * tree. - */ - while (bitmap_full(p->bitmap, IDR_SIZE)) { - if (!(p = pa[++l])) - break; - id = id >> IDR_BITS; - __set_bit((id & IDR_MASK), p->bitmap); - } -} - -static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) -{ - while (idp->id_free_cnt < MAX_IDR_FREE) { - struct idr_layer *new; - new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); - if (new == NULL) - return (0); - move_to_free_list(idp, new); - } - return 1; -} - -/** - * sub_alloc - try to allocate an id without growing the tree depth - * @idp: idr handle - * @starting_id: id to start search at - * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer - * @gfp_mask: allocation mask for idr_layer_alloc() - * @layer_idr: optional idr passed to idr_layer_alloc() - * - * Allocate an id in range [@starting_id, INT_MAX] from @idp without - * growing its depth. Returns - * - * the allocated id >= 0 if successful, - * -EAGAIN if the tree needs to grow for allocation to succeed, - * -ENOSPC if the id space is exhausted, - * -ENOMEM if more idr_layers need to be allocated. - */ -static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, - gfp_t gfp_mask, struct idr *layer_idr) -{ - int n, m, sh; - struct idr_layer *p, *new; - int l, id, oid; - - id = *starting_id; - restart: - p = idp->top; - l = idp->layers; - pa[l--] = NULL; - while (1) { - /* - * We run around this while until we reach the leaf node... - */ - n = (id >> (IDR_BITS*l)) & IDR_MASK; - m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); - if (m == IDR_SIZE) { - /* no space available go back to previous layer. */ - l++; - oid = id; - id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; - - /* if already at the top layer, we need to grow */ - if (id > idr_max(idp->layers)) { - *starting_id = id; - return -EAGAIN; - } - p = pa[l]; - BUG_ON(!p); - - /* If we need to go up one layer, continue the - * loop; otherwise, restart from the top. - */ - sh = IDR_BITS * (l + 1); - if (oid >> sh == id >> sh) - continue; - else - goto restart; - } - if (m != n) { - sh = IDR_BITS*l; - id = ((id >> sh) ^ n ^ m) << sh; - } - if ((id >= MAX_IDR_BIT) || (id < 0)) - return -ENOSPC; - if (l == 0) - break; - /* - * Create the layer below if it is missing. - */ - if (!p->ary[m]) { - new = idr_layer_alloc(gfp_mask, layer_idr); - if (!new) - return -ENOMEM; - new->layer = l-1; - new->prefix = id & idr_layer_prefix_mask(new->layer); - rcu_assign_pointer(p->ary[m], new); - p->count++; - } - pa[l--] = p; - p = p->ary[m]; - } - - pa[l] = p; - return id; -} - -static int idr_get_empty_slot(struct idr *idp, int starting_id, - struct idr_layer **pa, gfp_t gfp_mask, - struct idr *layer_idr) -{ - struct idr_layer *p, *new; - int layers, v, id; - unsigned long flags; - - id = starting_id; -build_up: - p = idp->top; - layers = idp->layers; - if (unlikely(!p)) { - if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) - return -ENOMEM; - p->layer = 0; - layers = 1; - } - /* - * Add a new layer to the top of the tree if the requested - * id is larger than the currently allocated space. - */ - while (id > idr_max(layers)) { - layers++; - if (!p->count) { - /* special case: if the tree is currently empty, - * then we grow the tree by moving the top node - * upwards. - */ - p->layer++; - WARN_ON_ONCE(p->prefix); - continue; - } - if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { - /* - * The allocation failed. If we built part of - * the structure tear it down. - */ - spin_lock_irqsave(&idp->lock, flags); - for (new = p; p && p != idp->top; new = p) { - p = p->ary[0]; - new->ary[0] = NULL; - new->count = 0; - bitmap_clear(new->bitmap, 0, IDR_SIZE); - __move_to_free_list(idp, new); - } - spin_unlock_irqrestore(&idp->lock, flags); - return -ENOMEM; - } - new->ary[0] = p; - new->count = 1; - new->layer = layers-1; - new->prefix = id & idr_layer_prefix_mask(new->layer); - if (bitmap_full(p->bitmap, IDR_SIZE)) - __set_bit(0, new->bitmap); - p = new; - } - rcu_assign_pointer(idp->top, p); - idp->layers = layers; - v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); - if (v == -EAGAIN) - goto build_up; - return(v); -} - -/* - * @id and @pa are from a successful allocation from idr_get_empty_slot(). - * Install the user pointer @ptr and mark the slot full. - */ -static void idr_fill_slot(struct idr *idr, void *ptr, int id, - struct idr_layer **pa) -{ - /* update hint used for lookup, cleared from free_layer() */ - rcu_assign_pointer(idr->hint, pa[0]); - - rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); - pa[0]->count++; - idr_mark_full(pa, id); -} - - -/** - * idr_preload - preload for idr_alloc() - * @gfp_mask: allocation mask to use for preloading - * - * Preload per-cpu layer buffer for idr_alloc(). Can only be used from - * process context and each idr_preload() invocation should be matched with - * idr_preload_end(). Note that preemption is disabled while preloaded. - * - * The first idr_alloc() in the preloaded section can be treated as if it - * were invoked with @gfp_mask used for preloading. This allows using more - * permissive allocation masks for idrs protected by spinlocks. - * - * For example, if idr_alloc() below fails, the failure can be treated as - * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. - * - * idr_preload(GFP_KERNEL); - * spin_lock(lock); - * - * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); - * - * spin_unlock(lock); - * idr_preload_end(); - * if (id < 0) - * error; - */ -void idr_preload(gfp_t gfp_mask) -{ - /* - * Consuming preload buffer from non-process context breaks preload - * allocation guarantee. Disallow usage from those contexts. - */ - WARN_ON_ONCE(in_interrupt()); - might_sleep_if(gfpflags_allow_blocking(gfp_mask)); - - preempt_disable(); - - /* - * idr_alloc() is likely to succeed w/o full idr_layer buffer and - * return value from idr_alloc() needs to be checked for failure - * anyway. Silently give up if allocation fails. The caller can - * treat failures from idr_alloc() as if idr_alloc() were called - * with @gfp_mask which should be enough. - */ - while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { - struct idr_layer *new; - - preempt_enable(); - new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); - preempt_disable(); - if (!new) - break; - - /* link the new one to per-cpu preload list */ - new->ary[0] = __this_cpu_read(idr_preload_head); - __this_cpu_write(idr_preload_head, new); - __this_cpu_inc(idr_preload_cnt); - } -} -EXPORT_SYMBOL(idr_preload); - /** - * idr_alloc - allocate new idr entry - * @idr: the (initialized) idr + * idr_alloc - allocate an id + * @idr: idr handle * @ptr: pointer to be associated with the new id * @start: the minimum id (inclusive) - * @end: the maximum id (exclusive, <= 0 for max) - * @gfp_mask: memory allocation flags + * @end: the maximum id (exclusive) + * @gfp: memory allocation flags * - * Allocate an id in [start, end) and associate it with @ptr. If no ID is - * available in the specified range, returns -ENOSPC. On memory allocation - * failure, returns -ENOMEM. + * Allocates an unused ID in the range [start, end). Returns -ENOSPC + * if there are no unused IDs in that range. * * Note that @end is treated as max when <= 0. This is to always allow * using @start + N as @end as long as N is inside integer range. * - * The user is responsible for exclusively synchronizing all operations - * which may modify @idr. However, read-only accesses such as idr_find() - * or iteration can be performed under RCU read lock provided the user - * destroys @ptr in RCU-safe way after removal from idr. + * Simultaneous modifications to the @idr are not allowed and should be + * prevented by the user, usually with a lock. idr_alloc() may be called + * concurrently with read-only accesses to the @idr, such as idr_find() and + * idr_for_each_entry(). */ -int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) +int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp) { - int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ - struct idr_layer *pa[MAX_IDR_LEVEL + 1]; - int id; - - might_sleep_if(gfpflags_allow_blocking(gfp_mask)); + void **slot; + struct radix_tree_iter iter; - /* sanity checks */ if (WARN_ON_ONCE(start < 0)) return -EINVAL; - if (unlikely(max < start)) - return -ENOSPC; + if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr))) + return -EINVAL; - /* allocate id */ - id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); - if (unlikely(id < 0)) - return id; - if (unlikely(id > max)) - return -ENOSPC; + radix_tree_iter_init(&iter, start); + slot = idr_get_free(&idr->idr_rt, &iter, gfp, end); + if (IS_ERR(slot)) + return PTR_ERR(slot); - idr_fill_slot(idr, ptr, id, pa); - return id; + radix_tree_iter_replace(&idr->idr_rt, &iter, slot, ptr); + radix_tree_iter_tag_clear(&idr->idr_rt, &iter, IDR_FREE); + return iter.index; } EXPORT_SYMBOL_GPL(idr_alloc); /** * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion - * @idr: the (initialized) idr + * @idr: idr handle * @ptr: pointer to be associated with the new id * @start: the minimum id (inclusive) - * @end: the maximum id (exclusive, <= 0 for max) - * @gfp_mask: memory allocation flags - * - * Essentially the same as idr_alloc, but prefers to allocate progressively - * higher ids if it can. If the "cur" counter wraps, then it will start again - * at the "start" end of the range and allocate one that has already been used. - */ -int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, - gfp_t gfp_mask) -{ - int id; - - id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask); - if (id == -ENOSPC) - id = idr_alloc(idr, ptr, start, end, gfp_mask); - - if (likely(id >= 0)) - idr->cur = id + 1; - return id; -} -EXPORT_SYMBOL(idr_alloc_cyclic); - -static void idr_remove_warning(int id) -{ - WARN(1, "idr_remove called for id=%d which is not allocated.\n", id); -} - -static void sub_remove(struct idr *idp, int shift, int id) -{ - struct idr_layer *p = idp->top; - struct idr_layer **pa[MAX_IDR_LEVEL + 1]; - struct idr_layer ***paa = &pa[0]; - struct idr_layer *to_free; - int n; - - *paa = NULL; - *++paa = &idp->top; - - while ((shift > 0) && p) { - n = (id >> shift) & IDR_MASK; - __clear_bit(n, p->bitmap); - *++paa = &p->ary[n]; - p = p->ary[n]; - shift -= IDR_BITS; - } - n = id & IDR_MASK; - if (likely(p != NULL && test_bit(n, p->bitmap))) { - __clear_bit(n, p->bitmap); - RCU_INIT_POINTER(p->ary[n], NULL); - to_free = NULL; - while(*paa && ! --((**paa)->count)){ - if (to_free) - free_layer(idp, to_free); - to_free = **paa; - **paa-- = NULL; - } - if (!*paa) - idp->layers = 0; - if (to_free) - free_layer(idp, to_free); - } else - idr_remove_warning(id); -} - -/** - * idr_remove - remove the given id and free its slot - * @idp: idr handle - * @id: unique key - */ -void idr_remove(struct idr *idp, int id) -{ - struct idr_layer *p; - struct idr_layer *to_free; - - if (id < 0) - return; - - if (id > idr_max(idp->layers)) { - idr_remove_warning(id); - return; - } - - sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); - if (idp->top && idp->top->count == 1 && (idp->layers > 1) && - idp->top->ary[0]) { - /* - * Single child at leftmost slot: we can shrink the tree. - * This level is not needed anymore since when layers are - * inserted, they are inserted at the top of the existing - * tree. - */ - to_free = idp->top; - p = idp->top->ary[0]; - rcu_assign_pointer(idp->top, p); - --idp->layers; - to_free->count = 0; - bitmap_clear(to_free->bitmap, 0, IDR_SIZE); - free_layer(idp, to_free); - } -} -EXPORT_SYMBOL(idr_remove); - -static void __idr_remove_all(struct idr *idp) -{ - int n, id, max; - int bt_mask; - struct idr_layer *p; - struct idr_layer *pa[MAX_IDR_LEVEL + 1]; - struct idr_layer **paa = &pa[0]; - - n = idp->layers * IDR_BITS; - *paa = idp->top; - RCU_INIT_POINTER(idp->top, NULL); - max = idr_max(idp->layers); - - id = 0; - while (id >= 0 && id <= max) { - p = *paa; - while (n > IDR_BITS && p) { - n -= IDR_BITS; - p = p->ary[(id >> n) & IDR_MASK]; - *++paa = p; - } - - bt_mask = id; - id += 1 << n; - /* Get the highest bit that the above add changed from 0->1. */ - while (n < fls(id ^ bt_mask)) { - if (*paa) - free_layer(idp, *paa); - n += IDR_BITS; - --paa; - } - } - idp->layers = 0; -} - -/** - * idr_destroy - release all cached layers within an idr tree - * @idp: idr handle - * - * Free all id mappings and all idp_layers. After this function, @idp is - * completely unused and can be freed / recycled. The caller is - * responsible for ensuring that no one else accesses @idp during or after - * idr_destroy(). + * @end: the maximum id (exclusive) + * @gfp: memory allocation flags * - * A typical clean-up sequence for objects stored in an idr tree will use - * idr_for_each() to free all objects, if necessary, then idr_destroy() to - * free up the id mappings and cached idr_layers. + * Allocates an ID larger than the last ID allocated if one is available. + * If not, it will attempt to allocate the smallest ID that is larger or + * equal to @start. */ -void idr_destroy(struct idr *idp) -{ - __idr_remove_all(idp); - - while (idp->id_free_cnt) { - struct idr_layer *p = get_from_free_list(idp); - kmem_cache_free(idr_layer_cache, p); - } -} -EXPORT_SYMBOL(idr_destroy); - -void *idr_find_slowpath(struct idr *idp, int id) +int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp) { - int n; - struct idr_layer *p; + int id, curr = idr->idr_next; - if (id < 0) - return NULL; + if (curr < start) + curr = start; - p = rcu_dereference_raw(idp->top); - if (!p) - return NULL; - n = (p->layer+1) * IDR_BITS; + id = idr_alloc(idr, ptr, curr, end, gfp); + if ((id == -ENOSPC) && (curr > start)) + id = idr_alloc(idr, ptr, start, curr, gfp); - if (id > idr_max(p->layer + 1)) - return NULL; - BUG_ON(n == 0); + if (id >= 0) + idr->idr_next = id + 1U; - while (n > 0 && p) { - n -= IDR_BITS; - BUG_ON(n != p->layer*IDR_BITS); - p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); - } - return((void *)p); + return id; } -EXPORT_SYMBOL(idr_find_slowpath); +EXPORT_SYMBOL(idr_alloc_cyclic); /** * idr_for_each - iterate through all stored pointers - * @idp: idr handle + * @idr: idr handle * @fn: function to be called for each pointer - * @data: data passed back to callback function + * @data: data passed to callback function * - * Iterate over the pointers registered with the given idr. The - * callback function will be called for each pointer currently - * registered, passing the id, the pointer and the data pointer passed - * to this function. It is not safe to modify the idr tree while in - * the callback, so functions such as idr_get_new and idr_remove are - * not allowed. + * The callback function will be called for each entry in @idr, passing + * the id, the pointer and the data pointer passed to this function. * - * We check the return of @fn each time. If it returns anything other - * than %0, we break out and return that value. + * If @fn returns anything other than %0, the iteration stops and that + * value is returned from this function. * - * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). + * idr_for_each() can be called concurrently with idr_alloc() and + * idr_remove() if protected by RCU. Newly added entries may not be + * seen and deleted entries may be seen, but adding and removing entries + * will not cause other entries to be skipped, nor spurious ones to be seen. */ -int idr_for_each(struct idr *idp, - int (*fn)(int id, void *p, void *data), void *data) +int idr_for_each(const struct idr *idr, + int (*fn)(int id, void *p, void *data), void *data) { - int n, id, max, error = 0; - struct idr_layer *p; - struct idr_layer *pa[MAX_IDR_LEVEL + 1]; - struct idr_layer **paa = &pa[0]; - - n = idp->layers * IDR_BITS; - *paa = rcu_dereference_raw(idp->top); - max = idr_max(idp->layers); - - id = 0; - while (id >= 0 && id <= max) { - p = *paa; - while (n > 0 && p) { - n -= IDR_BITS; - p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); - *++paa = p; - } - - if (p) { - error = fn(id, (void *)p, data); - if (error) - break; - } + struct radix_tree_iter iter; + void **slot; - id += 1 << n; - while (n < fls(id)) { - n += IDR_BITS; - --paa; - } + radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, 0) { + int ret = fn(iter.index, rcu_dereference_raw(*slot), data); + if (ret) + return ret; } - return error; + return 0; } EXPORT_SYMBOL(idr_for_each); /** - * idr_get_next - lookup next object of id to given id. - * @idp: idr handle - * @nextidp: pointer to lookup key - * - * Returns pointer to registered object with id, which is next number to - * given id. After being looked up, *@nextidp will be updated for the next - * iteration. - * - * This function can be called under rcu_read_lock(), given that the leaf - * pointers lifetimes are correctly managed. + * idr_get_next - Find next populated entry + * @idr: idr handle + * @nextid: Pointer to lowest possible ID to return + * + * Returns the next populated entry in the tree with an ID greater than + * or equal to the value pointed to by @nextid. On exit, @nextid is updated + * to the ID of the found value. To use in a loop, the value pointed to by + * nextid must be incremented by the user. */ -void *idr_get_next(struct idr *idp, int *nextidp) +void *idr_get_next(struct idr *idr, int *nextid) { - struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; - struct idr_layer **paa = &pa[0]; - int id = *nextidp; - int n, max; + struct radix_tree_iter iter; + void **slot; - /* find first ent */ - p = *paa = rcu_dereference_raw(idp->top); - if (!p) + slot = radix_tree_iter_find(&idr->idr_rt, &iter, *nextid); + if (!slot) return NULL; - n = (p->layer + 1) * IDR_BITS; - max = idr_max(p->layer + 1); - - while (id >= 0 && id <= max) { - p = *paa; - while (n > 0 && p) { - n -= IDR_BITS; - p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); - *++paa = p; - } - if (p) { - *nextidp = id; - return p; - } - - /* - * Proceed to the next layer at the current level. Unlike - * idr_for_each(), @id isn't guaranteed to be aligned to - * layer boundary at this point and adding 1 << n may - * incorrectly skip IDs. Make sure we jump to the - * beginning of the next layer using round_up(). - */ - id = round_up(id + 1, 1 << n); - while (n < fls(id)) { - n += IDR_BITS; - --paa; - } - } - return NULL; + *nextid = iter.index; + return rcu_dereference_raw(*slot); } EXPORT_SYMBOL(idr_get_next); - /** * idr_replace - replace pointer for given id - * @idp: idr handle - * @ptr: pointer you want associated with the id - * @id: lookup key + * @idr: idr handle + * @ptr: New pointer to associate with the ID + * @id: Lookup key * - * Replace the pointer registered with an id and return the old value. - * A %-ENOENT return indicates that @id was not found. - * A %-EINVAL return indicates that @id was not within valid constraints. + * Replace the pointer registered with an ID and return the old value. + * This function can be called under the RCU read lock concurrently with + * idr_alloc() and idr_remove() (as long as the ID being removed is not + * the one being replaced!). * - * The caller must serialize with writers. + * Returns: 0 on success. %-ENOENT indicates that @id was not found. + * %-EINVAL indicates that @id or @ptr were not valid. */ -void *idr_replace(struct idr *idp, void *ptr, int id) +void *idr_replace(struct idr *idr, void *ptr, int id) { - int n; - struct idr_layer *p, *old_p; + struct radix_tree_node *node; + void **slot = NULL; + void *entry; - if (id < 0) + if (WARN_ON_ONCE(id < 0)) + return ERR_PTR(-EINVAL); + if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr))) return ERR_PTR(-EINVAL); - p = idp->top; - if (!p) - return ERR_PTR(-ENOENT); - - if (id > idr_max(p->layer + 1)) - return ERR_PTR(-ENOENT); - - n = p->layer * IDR_BITS; - while ((n > 0) && p) { - p = p->ary[(id >> n) & IDR_MASK]; - n -= IDR_BITS; - } - - n = id & IDR_MASK; - if (unlikely(p == NULL || !test_bit(n, p->bitmap))) + entry = __radix_tree_lookup(&idr->idr_rt, id, &node, &slot); + if (!slot || radix_tree_tag_get(&idr->idr_rt, id, IDR_FREE)) return ERR_PTR(-ENOENT); - old_p = p->ary[n]; - rcu_assign_pointer(p->ary[n], ptr); + __radix_tree_replace(&idr->idr_rt, node, slot, ptr, NULL, NULL); - return old_p; + return entry; } EXPORT_SYMBOL(idr_replace); -void __init idr_init_cache(void) -{ - idr_layer_cache = kmem_cache_create("idr_layer_cache", - sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); -} - -/** - * idr_init - initialize idr handle - * @idp: idr handle - * - * This function is use to set up the handle (@idp) that you will pass - * to the rest of the functions. - */ -void idr_init(struct idr *idp) -{ - memset(idp, 0, sizeof(struct idr)); - spin_lock_init(&idp->lock); -} -EXPORT_SYMBOL(idr_init); - -static int idr_has_entry(int id, void *p, void *data) -{ - return 1; -} - -bool idr_is_empty(struct idr *idp) -{ - return !idr_for_each(idp, idr_has_entry, NULL); -} -EXPORT_SYMBOL(idr_is_empty); - /** * DOC: IDA description - * IDA - IDR based ID allocator - * - * This is id allocator without id -> pointer translation. Memory - * usage is much lower than full blown idr because each id only - * occupies a bit. ida uses a custom leaf node which contains - * IDA_BITMAP_BITS slots. * - * 2007-04-25 written by Tejun Heo + * The IDA is an ID allocator which does not provide the ability to + * associate an ID with a pointer. As such, it only needs to store one + * bit per ID, and so is more space efficient than an IDR. To use an IDA, + * define it using DEFINE_IDA() (or embed a &struct ida in a data structure, + * then initialise it using ida_init()). To allocate a new ID, call + * ida_simple_get(). To free an ID, call ida_simple_remove(). + * + * If you have more complex locking requirements, use a loop around + * ida_pre_get() and ida_get_new() to allocate a new ID. Then use + * ida_remove() to free an ID. You must make sure that ida_get_new() and + * ida_remove() cannot be called at the same time as each other for the + * same IDA. + * + * You can also use ida_get_new_above() if you need an ID to be allocated + * above a particular number. ida_destroy() can be used to dispose of an + * IDA without needing to free the individual IDs in it. You can use + * ida_is_empty() to find out whether the IDA has any IDs currently allocated. + * + * IDs are currently limited to the range [0-INT_MAX]. If this is an awkward + * limitation, it should be quite straightforward to raise the maximum. */ -static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) -{ - unsigned long flags; - - if (!ida->free_bitmap) { - spin_lock_irqsave(&ida->idr.lock, flags); - if (!ida->free_bitmap) { - ida->free_bitmap = bitmap; - bitmap = NULL; - } - spin_unlock_irqrestore(&ida->idr.lock, flags); - } - - kfree(bitmap); -} - /** * ida_pre_get - reserve resources for ida allocation - * @ida: ida handle - * @gfp_mask: memory allocation flag - * - * This function should be called prior to locking and calling the - * following function. It preallocates enough memory to satisfy the - * worst possible allocation. + * @ida: ida handle + * @gfp: memory allocation flags * - * If the system is REALLY out of memory this function returns %0, - * otherwise %1. + * This function should be called before calling ida_get_new_above(). If it + * is unable to allocate memory, it will return %0. On success, it returns %1. */ -int ida_pre_get(struct ida *ida, gfp_t gfp_mask) +int ida_pre_get(struct ida *ida, gfp_t gfp) { - /* allocate idr_layers */ - if (!__idr_pre_get(&ida->idr, gfp_mask)) - return 0; + struct ida_bitmap *bitmap; - /* allocate free_bitmap */ - if (!ida->free_bitmap) { - struct ida_bitmap *bitmap; + /* + * This looks weird, but the IDA API has no preload_end() equivalent. + * Instead, ida_get_new() can return -EAGAIN, prompting the caller + * to return to the ida_pre_get() step. + */ + idr_preload(gfp); + idr_preload_end(); - bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); + if (!ida->free_bitmap) { + bitmap = kmalloc(sizeof(struct ida_bitmap), gfp); if (!bitmap) return 0; - - free_bitmap(ida, bitmap); + bitmap = xchg(&ida->free_bitmap, bitmap); + kfree(bitmap); } return 1; } EXPORT_SYMBOL(ida_pre_get); +#define IDA_MAX (0x80000000U / IDA_BITMAP_BITS) + /** * ida_get_new_above - allocate new ID above or equal to a start id - * @ida: ida handle - * @starting_id: id to start search at - * @p_id: pointer to the allocated handle + * @ida: ida handle + * @start: id to start search at + * @id: pointer to the allocated handle * - * Allocate new ID above or equal to @starting_id. It should be called - * with any required locks. + * Allocate new ID above or equal to @start. It should be called + * with any required locks to ensure that concurrent calls to + * ida_get_new_above() / ida_get_new() / ida_remove() are not allowed. + * Consider using ida_simple_get() if you do not have complex locking + * requirements. * * If memory is required, it will return %-EAGAIN, you should unlock * and go back to the ida_pre_get() call. If the ida is full, it will - * return %-ENOSPC. - * - * Note that callers must ensure that concurrent access to @ida is not possible. - * See ida_simple_get() for a varaint which takes care of locking. + * return %-ENOSPC. On success, it will return 0. * - * @p_id returns a value in the range @starting_id ... %0x7fffffff. + * @id returns a value in the range @start ... %0x7fffffff. */ -int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) +int ida_get_new_above(struct ida *ida, int start, int *id) { - struct idr_layer *pa[MAX_IDR_LEVEL + 1]; + struct radix_tree_root *root = &ida->ida_rt; + void **slot; + struct radix_tree_iter iter; struct ida_bitmap *bitmap; - unsigned long flags; - int idr_id = starting_id / IDA_BITMAP_BITS; - int offset = starting_id % IDA_BITMAP_BITS; - int t, id; - - restart: - /* get vacant slot */ - t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); - if (t < 0) - return t == -ENOMEM ? -EAGAIN : t; - - if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) - return -ENOSPC; - - if (t != idr_id) - offset = 0; - idr_id = t; - - /* if bitmap isn't there, create a new one */ - bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; - if (!bitmap) { - spin_lock_irqsave(&ida->idr.lock, flags); - bitmap = ida->free_bitmap; - ida->free_bitmap = NULL; - spin_unlock_irqrestore(&ida->idr.lock, flags); - - if (!bitmap) - return -EAGAIN; - - memset(bitmap, 0, sizeof(struct ida_bitmap)); - rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], - (void *)bitmap); - pa[0]->count++; - } - - /* lookup for empty slot */ - t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); - if (t == IDA_BITMAP_BITS) { - /* no empty slot after offset, continue to the next chunk */ - idr_id++; - offset = 0; - goto restart; - } - - id = idr_id * IDA_BITMAP_BITS + t; - if (id >= MAX_IDR_BIT) - return -ENOSPC; - - __set_bit(t, bitmap->bitmap); - if (++bitmap->nr_busy == IDA_BITMAP_BITS) - idr_mark_full(pa, idr_id); + unsigned long index; + unsigned bit; + int new; + + index = start / IDA_BITMAP_BITS; + bit = start % IDA_BITMAP_BITS; + + slot = radix_tree_iter_init(&iter, index); + for (;;) { + if (slot) + slot = radix_tree_next_slot(slot, &iter, + RADIX_TREE_ITER_TAGGED); + if (!slot) { + slot = idr_get_free(root, &iter, GFP_NOWAIT, IDA_MAX); + if (IS_ERR(slot)) { + if (slot == ERR_PTR(-ENOMEM)) + return -EAGAIN; + return PTR_ERR(slot); + } + } + if (iter.index > index) + bit = 0; + new = iter.index * IDA_BITMAP_BITS; + bitmap = rcu_dereference_raw(*slot); + if (bitmap) { + bit = find_next_zero_bit(bitmap->bitmap, + IDA_BITMAP_BITS, bit); + new += bit; + if (new < 0) + return -ENOSPC; + if (bit == IDA_BITMAP_BITS) + continue; - *p_id = id; + __set_bit(bit, bitmap->bitmap); + if (bitmap_full(bitmap->bitmap, IDA_BITMAP_BITS)) + radix_tree_iter_tag_clear(root, &iter, + IDR_FREE); + } else { + new += bit; + if (new < 0) + return -ENOSPC; + bitmap = ida->free_bitmap; + if (!bitmap) + return -EAGAIN; + ida->free_bitmap = NULL; + memset(bitmap, 0, sizeof(*bitmap)); + __set_bit(bit, bitmap->bitmap); + radix_tree_iter_replace(root, &iter, slot, bitmap); + } - /* Each leaf node can handle nearly a thousand slots and the - * whole idea of ida is to have small memory foot print. - * Throw away extra resources one by one after each successful - * allocation. - */ - if (ida->idr.id_free_cnt || ida->free_bitmap) { - struct idr_layer *p = get_from_free_list(&ida->idr); - if (p) - kmem_cache_free(idr_layer_cache, p); + *id = new; + return 0; } - - return 0; } EXPORT_SYMBOL(ida_get_new_above); /** - * ida_remove - remove the given ID - * @ida: ida handle - * @id: ID to free + * ida_remove - Free the given ID + * @ida: ida handle + * @id: ID to free + * + * This function should not be called at the same time as ida_get_new_above(). */ void ida_remove(struct ida *ida, int id) { - struct idr_layer *p = ida->idr.top; - int shift = (ida->idr.layers - 1) * IDR_BITS; - int idr_id = id / IDA_BITMAP_BITS; - int offset = id % IDA_BITMAP_BITS; - int n; + unsigned long index = id / IDA_BITMAP_BITS; + unsigned offset = id % IDA_BITMAP_BITS; struct ida_bitmap *bitmap; + struct radix_tree_iter iter; + void **slot; - if (idr_id > idr_max(ida->idr.layers)) + slot = radix_tree_iter_lookup(&ida->ida_rt, &iter, index); + if (!slot) goto err; - /* clear full bits while looking up the leaf idr_layer */ - while ((shift > 0) && p) { - n = (idr_id >> shift) & IDR_MASK; - __clear_bit(n, p->bitmap); - p = p->ary[n]; - shift -= IDR_BITS; - } - - if (p == NULL) - goto err; - - n = idr_id & IDR_MASK; - __clear_bit(n, p->bitmap); - - bitmap = (void *)p->ary[n]; - if (!bitmap || !test_bit(offset, bitmap->bitmap)) + bitmap = rcu_dereference_raw(*slot); + if (!test_bit(offset, bitmap->bitmap)) goto err; - /* update bitmap and remove it if empty */ __clear_bit(offset, bitmap->bitmap); - if (--bitmap->nr_busy == 0) { - __set_bit(n, p->bitmap); /* to please idr_remove() */ - idr_remove(&ida->idr, idr_id); - free_bitmap(ida, bitmap); + radix_tree_iter_tag_set(&ida->ida_rt, &iter, IDR_FREE); + if (bitmap_empty(bitmap->bitmap, IDA_BITMAP_BITS)) { + kfree(bitmap); + radix_tree_iter_delete(&ida->ida_rt, &iter, slot); } - return; - err: WARN(1, "ida_remove called for id=%d which is not allocated.\n", id); } EXPORT_SYMBOL(ida_remove); /** - * ida_destroy - release all cached layers within an ida tree - * @ida: ida handle + * ida_destroy - Free the contents of an ida + * @ida: ida handle + * + * Calling this function releases all resources associated with an IDA. When + * this call returns, the IDA is empty and can be reused or freed. The caller + * should not allow ida_remove() or ida_get_new_above() to be called at the + * same time. */ void ida_destroy(struct ida *ida) { - idr_destroy(&ida->idr); + struct radix_tree_iter iter; + void **slot; + + radix_tree_for_each_slot(slot, &ida->ida_rt, &iter, 0) { + struct ida_bitmap *bitmap = rcu_dereference_raw(*slot); + kfree(bitmap); + radix_tree_iter_delete(&ida->ida_rt, &iter, slot); + } + kfree(ida->free_bitmap); + ida->free_bitmap = NULL; } EXPORT_SYMBOL(ida_destroy); @@ -1141,18 +442,3 @@ void ida_simple_remove(struct ida *ida, unsigned int id) spin_unlock_irqrestore(&simple_ida_lock, flags); } EXPORT_SYMBOL(ida_simple_remove); - -/** - * ida_init - initialize ida handle - * @ida: ida handle - * - * This function is use to set up the handle (@ida) that you will pass - * to the rest of the functions. - */ -void ida_init(struct ida *ida) -{ - memset(ida, 0, sizeof(struct ida)); - idr_init(&ida->idr); - -} -EXPORT_SYMBOL(ida_init); diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 7bf7d4e60e43..eaea14b8f2ca 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -22,20 +22,21 @@ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ +#include +#include #include #include +#include +#include #include #include -#include -#include +#include #include +#include /* in_interrupt() */ +#include +#include #include -#include -#include #include -#include -#include -#include /* in_interrupt() */ /* Number of nodes in fully populated tree of given height */ @@ -59,6 +60,15 @@ static struct kmem_cache *radix_tree_node_cachep; */ #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1) +/* + * The IDR does not have to be as high as the radix tree since it uses + * signed integers, not unsigned longs. + */ +#define IDR_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(int) - 1) +#define IDR_MAX_PATH (DIV_ROUND_UP(IDR_INDEX_BITS, \ + RADIX_TREE_MAP_SHIFT)) +#define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1) + /* * Per-cpu pool of preloaded nodes */ @@ -149,27 +159,32 @@ static inline int tag_get(const struct radix_tree_node *node, unsigned int tag, static inline void root_tag_set(struct radix_tree_root *root, unsigned tag) { - root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); + root->gfp_mask |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT)); } static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag) { - root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); + root->gfp_mask &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT)); } static inline void root_tag_clear_all(struct radix_tree_root *root) { - root->gfp_mask &= __GFP_BITS_MASK; + root->gfp_mask &= (1 << ROOT_TAG_SHIFT) - 1; } static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag) { - return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); + return (__force int)root->gfp_mask & (1 << (tag + ROOT_TAG_SHIFT)); } static inline unsigned root_tags_get(const struct radix_tree_root *root) { - return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT; + return (__force unsigned)root->gfp_mask >> ROOT_TAG_SHIFT; +} + +static inline bool is_idr(const struct radix_tree_root *root) +{ + return !!(root->gfp_mask & ROOT_IS_IDR); } /* @@ -187,6 +202,11 @@ static inline int any_tag_set(const struct radix_tree_node *node, return 0; } +static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag) +{ + bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE); +} + /** * radix_tree_find_next_bit - find the next set bit in a memory region * @@ -240,6 +260,13 @@ static inline unsigned long node_maxindex(const struct radix_tree_node *node) return shift_maxindex(node->shift); } +static unsigned long next_index(unsigned long index, + const struct radix_tree_node *node, + unsigned long offset) +{ + return (index & ~node_maxindex(node)) + (offset << node->shift); +} + #ifndef __KERNEL__ static void dump_node(struct radix_tree_node *node, unsigned long index) { @@ -278,11 +305,52 @@ static void radix_tree_dump(struct radix_tree_root *root) { pr_debug("radix root: %p rnode %p tags %x\n", root, root->rnode, - root->gfp_mask >> __GFP_BITS_SHIFT); + root->gfp_mask >> ROOT_TAG_SHIFT); if (!radix_tree_is_internal_node(root->rnode)) return; dump_node(entry_to_node(root->rnode), 0); } + +static void dump_ida_node(void *entry, unsigned long index) +{ + unsigned long i; + + if (!entry) + return; + + if (radix_tree_is_internal_node(entry)) { + struct radix_tree_node *node = entry_to_node(entry); + + pr_debug("ida node: %p offset %d indices %lu-%lu parent %p free %lx shift %d count %d\n", + node, node->offset, index * IDA_BITMAP_BITS, + ((index | node_maxindex(node)) + 1) * + IDA_BITMAP_BITS - 1, + node->parent, node->tags[0][0], node->shift, + node->count); + for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) + dump_ida_node(node->slots[i], + index | (i << node->shift)); + } else { + struct ida_bitmap *bitmap = entry; + + pr_debug("ida btmp: %p offset %d indices %lu-%lu data", bitmap, + (int)(index & RADIX_TREE_MAP_MASK), + index * IDA_BITMAP_BITS, + (index + 1) * IDA_BITMAP_BITS - 1); + for (i = 0; i < IDA_BITMAP_LONGS; i++) + pr_cont(" %lx", bitmap->bitmap[i]); + pr_cont("\n"); + } +} + +static void ida_dump(struct ida *ida) +{ + struct radix_tree_root *root = &ida->ida_rt; + pr_debug("ida: %p %p free %d bitmap %p\n", ida, root->rnode, + root->gfp_mask >> ROOT_TAG_SHIFT, + ida->free_bitmap); + dump_ida_node(root->rnode, 0); +} #endif /* @@ -290,13 +358,11 @@ static void radix_tree_dump(struct radix_tree_root *root) * that the caller has pinned this thread of control to the current CPU. */ static struct radix_tree_node * -radix_tree_node_alloc(struct radix_tree_root *root, - struct radix_tree_node *parent, +radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent, unsigned int shift, unsigned int offset, unsigned int count, unsigned int exceptional) { struct radix_tree_node *ret = NULL; - gfp_t gfp_mask = root_gfp_mask(root); /* * Preload code isn't irq safe and it doesn't make sense to use @@ -533,7 +599,7 @@ static unsigned radix_tree_load_root(const struct radix_tree_root *root, /* * Extend a radix tree so it can store key @index. */ -static int radix_tree_extend(struct radix_tree_root *root, +static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, unsigned long index, unsigned int shift) { struct radix_tree_node *slot; @@ -546,19 +612,27 @@ static int radix_tree_extend(struct radix_tree_root *root, maxshift += RADIX_TREE_MAP_SHIFT; slot = root->rnode; - if (!slot) + if (!slot && (!is_idr(root) || root_tag_get(root, IDR_FREE))) goto out; do { - struct radix_tree_node *node = radix_tree_node_alloc(root, - NULL, shift, 0, 1, 0); + struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL, + shift, 0, 1, 0); if (!node) return -ENOMEM; - /* Propagate the aggregated tag info into the new root */ - for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { - if (root_tag_get(root, tag)) - tag_set(node, tag, 0); + if (is_idr(root)) { + all_tag_set(node, IDR_FREE); + if (!root_tag_get(root, IDR_FREE)) { + tag_clear(node, IDR_FREE, 0); + root_tag_set(root, IDR_FREE); + } + } else { + /* Propagate the aggregated tag info to the new child */ + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { + if (root_tag_get(root, tag)) + tag_set(node, tag, 0); + } } BUG_ON(shift > BITS_PER_LONG); @@ -619,6 +693,8 @@ static inline bool radix_tree_shrink(struct radix_tree_root *root, * one (root->rnode) as far as dependent read barriers go. */ root->rnode = child; + if (is_idr(root) && !tag_get(node, IDR_FREE, 0)) + root_tag_clear(root, IDR_FREE); /* * We have a dilemma here. The node's slot[0] must not be @@ -674,7 +750,12 @@ static bool delete_node(struct radix_tree_root *root, parent->slots[node->offset] = NULL; parent->count--; } else { - root_tag_clear_all(root); + /* + * Shouldn't the tags already have all been cleared + * by the caller? + */ + if (!is_idr(root)) + root_tag_clear_all(root); root->rnode = NULL; } @@ -714,6 +795,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, unsigned long maxindex; unsigned int shift, offset = 0; unsigned long max = index | ((1UL << order) - 1); + gfp_t gfp = root_gfp_mask(root); shift = radix_tree_load_root(root, &child, &maxindex); @@ -721,7 +803,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, if (order > 0 && max == ((1UL << order) - 1)) max++; if (max > maxindex) { - int error = radix_tree_extend(root, max, shift); + int error = radix_tree_extend(root, gfp, max, shift); if (error < 0) return error; shift = error; @@ -732,7 +814,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, shift -= RADIX_TREE_MAP_SHIFT; if (child == NULL) { /* Have to add a child node. */ - child = radix_tree_node_alloc(root, node, shift, + child = radix_tree_node_alloc(gfp, node, shift, offset, 0, 0); if (!child) return -ENOMEM; @@ -755,7 +837,6 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, return 0; } -#ifdef CONFIG_RADIX_TREE_MULTIORDER /* * Free any nodes below this node. The tree is presumed to not need * shrinking, and any user data in the tree is presumed to not need a @@ -791,6 +872,7 @@ static void radix_tree_free_nodes(struct radix_tree_node *node) } } +#ifdef CONFIG_RADIX_TREE_MULTIORDER static inline int insert_entries(struct radix_tree_node *node, void **slot, void *item, unsigned order, bool replace) { @@ -996,69 +1078,70 @@ void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index) } EXPORT_SYMBOL(radix_tree_lookup); -static inline int slot_count(struct radix_tree_node *node, - void **slot) +static inline void replace_sibling_entries(struct radix_tree_node *node, + void **slot, int count, int exceptional) { - int n = 1; #ifdef CONFIG_RADIX_TREE_MULTIORDER void *ptr = node_to_entry(slot); - unsigned offset = get_slot_offset(node, slot); - int i; + unsigned offset = get_slot_offset(node, slot) + 1; - for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) { - if (node->slots[offset + i] != ptr) + while (offset < RADIX_TREE_MAP_SIZE) { + if (node->slots[offset] != ptr) break; - n++; + if (count < 0) { + node->slots[offset] = NULL; + node->count--; + } + node->exceptional += exceptional; + offset++; } #endif - return n; } -static void replace_slot(struct radix_tree_root *root, - struct radix_tree_node *node, - void **slot, void *item, - bool warn_typeswitch) +static void replace_slot(void **slot, void *item, struct radix_tree_node *node, + int count, int exceptional) { - void *old = rcu_dereference_raw(*slot); - int count, exceptional; - - WARN_ON_ONCE(radix_tree_is_internal_node(item)); - - count = !!item - !!old; - exceptional = !!radix_tree_exceptional_entry(item) - - !!radix_tree_exceptional_entry(old); - - WARN_ON_ONCE(warn_typeswitch && (count || exceptional)); + if (WARN_ON_ONCE(radix_tree_is_internal_node(item))) + return; - if (node) { + if (node && (count || exceptional)) { node->count += count; - if (exceptional) { - exceptional *= slot_count(node, slot); - node->exceptional += exceptional; - } + node->exceptional += exceptional; + replace_sibling_entries(node, slot, count, exceptional); } rcu_assign_pointer(*slot, item); } -static inline void delete_sibling_entries(struct radix_tree_node *node, - void **slot) +static bool node_tag_get(const struct radix_tree_root *root, + const struct radix_tree_node *node, + unsigned int tag, unsigned int offset) { -#ifdef CONFIG_RADIX_TREE_MULTIORDER - bool exceptional = radix_tree_exceptional_entry(*slot); - void *ptr = node_to_entry(slot); - unsigned offset = get_slot_offset(node, slot); - int i; + if (node) + return tag_get(node, tag, offset); + return root_tag_get(root, tag); +} - for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) { - if (node->slots[offset + i] != ptr) - break; - node->slots[offset + i] = NULL; - node->count--; - if (exceptional) - node->exceptional--; +/* + * IDR users want to be able to store NULL in the tree, so if the slot isn't + * free, don't adjust the count, even if it's transitioning between NULL and + * non-NULL. For the IDA, we mark slots as being IDR_FREE while they still + * have empty bits, but it only stores NULL in slots when they're being + * deleted. + */ +static int calculate_count(struct radix_tree_root *root, + struct radix_tree_node *node, void **slot, + void *item, void *old) +{ + if (is_idr(root)) { + unsigned offset = get_slot_offset(node, slot); + bool free = node_tag_get(root, node, IDR_FREE, offset); + if (!free) + return 0; + if (!old) + return 1; } -#endif + return !!item - !!old; } /** @@ -1078,15 +1161,19 @@ void __radix_tree_replace(struct radix_tree_root *root, void **slot, void *item, radix_tree_update_node_t update_node, void *private) { - if (!item) - delete_sibling_entries(node, slot); + void *old = rcu_dereference_raw(*slot); + int exceptional = !!radix_tree_exceptional_entry(item) - + !!radix_tree_exceptional_entry(old); + int count = calculate_count(root, node, slot, item, old); + /* * This function supports replacing exceptional entries and * deleting entries, but that needs accounting against the * node unless the slot is root->rnode. */ - replace_slot(root, node, slot, item, - !node && slot != (void **)&root->rnode); + WARN_ON_ONCE(!node && (slot != (void **)&root->rnode) && + (count || exceptional)); + replace_slot(slot, item, node, count, exceptional); if (!node) return; @@ -1116,7 +1203,7 @@ void __radix_tree_replace(struct radix_tree_root *root, void radix_tree_replace_slot(struct radix_tree_root *root, void **slot, void *item) { - replace_slot(root, NULL, slot, item, true); + __radix_tree_replace(root, NULL, slot, item, NULL, NULL); } /** @@ -1191,6 +1278,7 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, void **slot; unsigned int offset, end; unsigned n, tag, tags = 0; + gfp_t gfp = root_gfp_mask(root); if (!__radix_tree_lookup(root, index, &parent, &slot)) return -ENOENT; @@ -1228,7 +1316,7 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, for (;;) { if (node->shift > order) { - child = radix_tree_node_alloc(root, node, + child = radix_tree_node_alloc(gfp, node, node->shift - RADIX_TREE_MAP_SHIFT, offset, 0, 0); if (!child) @@ -1444,8 +1532,6 @@ int radix_tree_tag_get(const struct radix_tree_root *root, radix_tree_load_root(root, &node, &maxindex); if (index > maxindex) return 0; - if (node == NULL) - return 0; while (radix_tree_is_internal_node(node)) { unsigned offset; @@ -1453,8 +1539,6 @@ int radix_tree_tag_get(const struct radix_tree_root *root, parent = entry_to_node(node); offset = radix_tree_descend(parent, &node, index); - if (!node) - return 0; if (!tag_get(parent, tag, offset)) return 0; if (node == RADIX_TREE_RETRY) @@ -1481,6 +1565,11 @@ static void set_iter_tags(struct radix_tree_iter *iter, unsigned tag_long = offset / BITS_PER_LONG; unsigned tag_bit = offset % BITS_PER_LONG; + if (!node) { + iter->tags = 1; + return; + } + iter->tags = node->tags[tag][tag_long] >> tag_bit; /* This never happens if RADIX_TREE_TAG_LONGS == 1 */ @@ -1873,13 +1962,18 @@ void __radix_tree_delete_node(struct radix_tree_root *root, static bool __radix_tree_delete(struct radix_tree_root *root, struct radix_tree_node *node, void **slot) { + void *old = rcu_dereference_raw(*slot); + int exceptional = radix_tree_exceptional_entry(old) ? -1 : 0; unsigned offset = get_slot_offset(node, slot); int tag; - for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) - node_tag_clear(root, node, tag, offset); + if (is_idr(root)) + node_tag_set(root, node, IDR_FREE, offset); + else + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) + node_tag_clear(root, node, tag, offset); - replace_slot(root, node, slot, NULL, true); + replace_slot(slot, NULL, node, -1, exceptional); return node && delete_node(root, node, NULL, NULL); } @@ -1916,12 +2010,13 @@ void radix_tree_iter_delete(struct radix_tree_root *root, void *radix_tree_delete_item(struct radix_tree_root *root, unsigned long index, void *item) { - struct radix_tree_node *node; + struct radix_tree_node *node = NULL; void **slot; void *entry; entry = __radix_tree_lookup(root, index, &node, &slot); - if (!entry) + if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE, + get_slot_offset(node, slot)))) return NULL; if (item && entry != item) @@ -1957,8 +2052,7 @@ void radix_tree_clear_tags(struct radix_tree_root *root, for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) node_tag_clear(root, node, tag, offset); } else { - /* Clear root node tags */ - root->gfp_mask &= __GFP_BITS_MASK; + root_tag_clear_all(root); } } @@ -1973,6 +2067,111 @@ int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag) } EXPORT_SYMBOL(radix_tree_tagged); +/** + * idr_preload - preload for idr_alloc() + * @gfp_mask: allocation mask to use for preloading + * + * Preallocate memory to use for the next call to idr_alloc(). This function + * returns with preemption disabled. It will be enabled by idr_preload_end(). + */ +void idr_preload(gfp_t gfp_mask) +{ + __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); +} +EXPORT_SYMBOL(idr_preload); + +void **idr_get_free(struct radix_tree_root *root, + struct radix_tree_iter *iter, gfp_t gfp, int end) +{ + struct radix_tree_node *node = NULL, *child; + void **slot = (void **)&root->rnode; + unsigned long maxindex, start = iter->next_index; + unsigned long max = end > 0 ? end - 1 : INT_MAX; + unsigned int shift, offset = 0; + + grow: + shift = radix_tree_load_root(root, &child, &maxindex); + if (!radix_tree_tagged(root, IDR_FREE)) + start = max(start, maxindex + 1); + if (start > max) + return ERR_PTR(-ENOSPC); + + if (start > maxindex) { + int error = radix_tree_extend(root, gfp, start, shift); + if (error < 0) + return ERR_PTR(error); + shift = error; + child = rcu_dereference_raw(root->rnode); + } + + while (shift) { + shift -= RADIX_TREE_MAP_SHIFT; + if (child == NULL) { + /* Have to add a child node. */ + child = radix_tree_node_alloc(gfp, node, shift, offset, + 0, 0); + if (!child) + return ERR_PTR(-ENOMEM); + all_tag_set(child, IDR_FREE); + rcu_assign_pointer(*slot, node_to_entry(child)); + if (node) + node->count++; + } else if (!radix_tree_is_internal_node(child)) + break; + + node = entry_to_node(child); + offset = radix_tree_descend(node, &child, start); + if (!tag_get(node, IDR_FREE, offset)) { + offset = radix_tree_find_next_bit(node, IDR_FREE, + offset + 1); + start = next_index(start, node, offset); + if (start > max) + return ERR_PTR(-ENOSPC); + while (offset == RADIX_TREE_MAP_SIZE) { + offset = node->offset + 1; + node = node->parent; + if (!node) + goto grow; + shift = node->shift; + } + child = rcu_dereference_raw(node->slots[offset]); + } + slot = &node->slots[offset]; + } + + iter->index = start; + if (node) + iter->next_index = 1 + min(max, (start | node_maxindex(node))); + else + iter->next_index = 1; + iter->node = node; + __set_iter_shift(iter, shift); + set_iter_tags(iter, node, offset, IDR_FREE); + + return slot; +} + +/** + * idr_destroy - release all internal memory from an IDR + * @idr: idr handle + * + * After this function is called, the IDR is empty, and may be reused or + * the data structure containing it may be freed. + * + * A typical clean-up sequence for objects stored in an idr tree will use + * idr_for_each() to free all objects, if necessary, then idr_destroy() to + * free the memory used to keep track of those objects. + */ +void idr_destroy(struct idr *idr) +{ + struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.rnode); + if (radix_tree_is_internal_node(node)) + radix_tree_free_nodes(node); + idr->idr_rt.rnode = NULL; + root_tag_set(&idr->idr_rt, IDR_FREE); +} +EXPORT_SYMBOL(idr_destroy); + static void radix_tree_node_ctor(void *arg) { diff --git a/tools/testing/radix-tree/.gitignore b/tools/testing/radix-tree/.gitignore index 11d888ca6a92..3b5534b643f0 100644 --- a/tools/testing/radix-tree/.gitignore +++ b/tools/testing/radix-tree/.gitignore @@ -1,2 +1,3 @@ main radix-tree.c +idr.c diff --git a/tools/testing/radix-tree/Makefile b/tools/testing/radix-tree/Makefile index 5274e88cd293..3597a3a9f269 100644 --- a/tools/testing/radix-tree/Makefile +++ b/tools/testing/radix-tree/Makefile @@ -2,8 +2,8 @@ CFLAGS += -I. -I../../include -g -O2 -Wall -D_LGPL_SOURCE LDFLAGS += -lpthread -lurcu TARGETS = main -OFILES = main.o radix-tree.o linux.o test.o tag_check.o find_bit.o \ - regression1.o regression2.o regression3.o multiorder.o \ +OFILES = main.o radix-tree.o idr.o linux.o test.o tag_check.o find_bit.o \ + regression1.o regression2.o regression3.o multiorder.o idr-test.o \ iteration_check.o benchmark.o ifdef BENCHMARK @@ -23,7 +23,11 @@ vpath %.c ../../lib $(OFILES): *.h */*.h \ ../../include/linux/*.h \ ../../include/asm/*.h \ - ../../../include/linux/radix-tree.h + ../../../include/linux/radix-tree.h \ + ../../../include/linux/idr.h radix-tree.c: ../../../lib/radix-tree.c sed -e 's/^static //' -e 's/__always_inline //' -e 's/inline //' < $< > $@ + +idr.c: ../../../lib/idr.c + sed -e 's/^static //' -e 's/__always_inline //' -e 's/inline //' < $< > $@ diff --git a/tools/testing/radix-tree/idr-test.c b/tools/testing/radix-tree/idr-test.c new file mode 100644 index 000000000000..4dffad9284e0 --- /dev/null +++ b/tools/testing/radix-tree/idr-test.c @@ -0,0 +1,342 @@ +/* + * idr-test.c: Test the IDR API + * Copyright (c) 2016 Matthew Wilcox + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include +#include +#include +#include + +#include "test.h" + +#define DUMMY_PTR ((void *)0x12) + +int item_idr_free(int id, void *p, void *data) +{ + struct item *item = p; + assert(item->index == id); + free(p); + + return 0; +} + +void item_idr_remove(struct idr *idr, int id) +{ + struct item *item = idr_find(idr, id); + assert(item->index == id); + idr_remove(idr, id); + free(item); +} + +void idr_alloc_test(void) +{ + unsigned long i; + DEFINE_IDR(idr); + + assert(idr_alloc_cyclic(&idr, DUMMY_PTR, 0, 0x4000, GFP_KERNEL) == 0); + assert(idr_alloc_cyclic(&idr, DUMMY_PTR, 0x3ffd, 0x4000, GFP_KERNEL) == 0x3ffd); + idr_remove(&idr, 0x3ffd); + idr_remove(&idr, 0); + + for (i = 0x3ffe; i < 0x4003; i++) { + int id; + struct item *item; + + if (i < 0x4000) + item = item_create(i, 0); + else + item = item_create(i - 0x3fff, 0); + + id = idr_alloc_cyclic(&idr, item, 1, 0x4000, GFP_KERNEL); + assert(id == item->index); + } + + idr_for_each(&idr, item_idr_free, &idr); + idr_destroy(&idr); +} + +void idr_replace_test(void) +{ + DEFINE_IDR(idr); + + idr_alloc(&idr, (void *)-1, 10, 11, GFP_KERNEL); + idr_replace(&idr, &idr, 10); + + idr_destroy(&idr); +} + +/* + * Unlike the radix tree, you can put a NULL pointer -- with care -- into + * the IDR. Some interfaces, like idr_find() do not distinguish between + * "present, value is NULL" and "not present", but that's exactly what some + * users want. + */ +void idr_null_test(void) +{ + int i; + DEFINE_IDR(idr); + + assert(idr_is_empty(&idr)); + + assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == 0); + assert(!idr_is_empty(&idr)); + idr_remove(&idr, 0); + assert(idr_is_empty(&idr)); + + assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == 0); + assert(!idr_is_empty(&idr)); + idr_destroy(&idr); + assert(idr_is_empty(&idr)); + + for (i = 0; i < 10; i++) { + assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == i); + } + + assert(idr_replace(&idr, DUMMY_PTR, 3) == NULL); + assert(idr_replace(&idr, DUMMY_PTR, 4) == NULL); + assert(idr_replace(&idr, NULL, 4) == DUMMY_PTR); + assert(idr_replace(&idr, DUMMY_PTR, 11) == ERR_PTR(-ENOENT)); + idr_remove(&idr, 5); + assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == 5); + idr_remove(&idr, 5); + + for (i = 0; i < 9; i++) { + idr_remove(&idr, i); + assert(!idr_is_empty(&idr)); + } + idr_remove(&idr, 8); + assert(!idr_is_empty(&idr)); + idr_remove(&idr, 9); + assert(idr_is_empty(&idr)); + + assert(idr_alloc(&idr, NULL, 0, 0, GFP_KERNEL) == 0); + assert(idr_replace(&idr, DUMMY_PTR, 3) == ERR_PTR(-ENOENT)); + assert(idr_replace(&idr, DUMMY_PTR, 0) == NULL); + assert(idr_replace(&idr, NULL, 0) == DUMMY_PTR); + + idr_destroy(&idr); + assert(idr_is_empty(&idr)); + + for (i = 1; i < 10; i++) { + assert(idr_alloc(&idr, NULL, 1, 0, GFP_KERNEL) == i); + } + + idr_destroy(&idr); + assert(idr_is_empty(&idr)); +} + +void idr_nowait_test(void) +{ + unsigned int i; + DEFINE_IDR(idr); + + idr_preload(GFP_KERNEL); + + for (i = 0; i < 3; i++) { + struct item *item = item_create(i, 0); + assert(idr_alloc(&idr, item, i, i + 1, GFP_NOWAIT) == i); + } + + idr_preload_end(); + + idr_for_each(&idr, item_idr_free, &idr); + idr_destroy(&idr); +} + +void idr_checks(void) +{ + unsigned long i; + DEFINE_IDR(idr); + + for (i = 0; i < 10000; i++) { + struct item *item = item_create(i, 0); + assert(idr_alloc(&idr, item, 0, 20000, GFP_KERNEL) == i); + } + + assert(idr_alloc(&idr, DUMMY_PTR, 5, 30, GFP_KERNEL) < 0); + + for (i = 0; i < 5000; i++) + item_idr_remove(&idr, i); + + idr_remove(&idr, 3); + + idr_for_each(&idr, item_idr_free, &idr); + idr_destroy(&idr); + + assert(idr_is_empty(&idr)); + + idr_remove(&idr, 3); + idr_remove(&idr, 0); + + for (i = INT_MAX - 3UL; i < INT_MAX + 1UL; i++) { + struct item *item = item_create(i, 0); + assert(idr_alloc(&idr, item, i, i + 10, GFP_KERNEL) == i); + } + assert(idr_alloc(&idr, DUMMY_PTR, i - 2, i, GFP_KERNEL) == -ENOSPC); + + idr_for_each(&idr, item_idr_free, &idr); + idr_destroy(&idr); + idr_destroy(&idr); + + assert(idr_is_empty(&idr)); + + for (i = 1; i < 10000; i++) { + struct item *item = item_create(i, 0); + assert(idr_alloc(&idr, item, 1, 20000, GFP_KERNEL) == i); + } + + idr_for_each(&idr, item_idr_free, &idr); + idr_destroy(&idr); + + idr_replace_test(); + idr_alloc_test(); + idr_null_test(); + idr_nowait_test(); +} + +/* + * Check that we get the correct error when we run out of memory doing + * allocations. To ensure we run out of memory, just "forget" to preload. + * The first test is for not having a bitmap available, and the second test + * is for not being able to allocate a level of the radix tree. + */ +void ida_check_nomem(void) +{ + DEFINE_IDA(ida); + int id, err; + + err = ida_get_new(&ida, &id); + assert(err == -EAGAIN); + err = ida_get_new_above(&ida, 1UL << 30, &id); + assert(err == -EAGAIN); +} + +/* + * Check what happens when we fill a leaf and then delete it. This may + * discover mishandling of IDR_FREE. + */ +void ida_check_leaf(void) +{ + DEFINE_IDA(ida); + int id; + unsigned long i; + + for (i = 0; i < IDA_BITMAP_BITS; i++) { + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new(&ida, &id)); + assert(id == i); + } + + ida_destroy(&ida); + assert(ida_is_empty(&ida)); + + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new(&ida, &id)); + assert(id == 0); + ida_destroy(&ida); + assert(ida_is_empty(&ida)); +} + +/* + * Check allocations up to and slightly above the maximum allowed (2^31-1) ID. + * Allocating up to 2^31-1 should succeed, and then allocating the next one + * should fail. + */ +void ida_check_max(void) +{ + DEFINE_IDA(ida); + int id, err; + unsigned long i, j; + + for (j = 1; j < 65537; j *= 2) { + unsigned long base = (1UL << 31) - j; + for (i = 0; i < j; i++) { + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new_above(&ida, base, &id)); + assert(id == base + i); + } + assert(ida_pre_get(&ida, GFP_KERNEL)); + err = ida_get_new_above(&ida, base, &id); + assert(err == -ENOSPC); + ida_destroy(&ida); + assert(ida_is_empty(&ida)); + rcu_barrier(); + } +} + +void ida_checks(void) +{ + DEFINE_IDA(ida); + int id; + unsigned long i; + + radix_tree_cpu_dead(1); + ida_check_nomem(); + + for (i = 0; i < 10000; i++) { + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new(&ida, &id)); + assert(id == i); + } + + ida_remove(&ida, 20); + ida_remove(&ida, 21); + for (i = 0; i < 3; i++) { + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new(&ida, &id)); + if (i == 2) + assert(id == 10000); + } + + for (i = 0; i < 5000; i++) + ida_remove(&ida, i); + + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new_above(&ida, 5000, &id)); + assert(id == 10001); + + ida_destroy(&ida); + + assert(ida_is_empty(&ida)); + + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new_above(&ida, 1, &id)); + assert(id == 1); + + ida_remove(&ida, id); + assert(ida_is_empty(&ida)); + ida_destroy(&ida); + assert(ida_is_empty(&ida)); + + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new_above(&ida, 1, &id)); + ida_destroy(&ida); + assert(ida_is_empty(&ida)); + + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new_above(&ida, 1, &id)); + assert(id == 1); + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new_above(&ida, 1025, &id)); + assert(id == 1025); + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new_above(&ida, 10000, &id)); + assert(id == 10000); + ida_remove(&ida, 1025); + ida_destroy(&ida); + assert(ida_is_empty(&ida)); + + ida_check_leaf(); + ida_check_max(); + + radix_tree_cpu_dead(1); +} diff --git a/tools/testing/radix-tree/linux/gfp.h b/tools/testing/radix-tree/linux/gfp.h index 701209816a6b..39a0dcb9475a 100644 --- a/tools/testing/radix-tree/linux/gfp.h +++ b/tools/testing/radix-tree/linux/gfp.h @@ -15,10 +15,12 @@ #define __GFP_DIRECT_RECLAIM 0x400000u #define __GFP_KSWAPD_RECLAIM 0x2000000u -#define __GFP_RECLAIM (__GFP_DIRECT_RECLAIM|__GFP_KSWAPD_RECLAIM) +#define __GFP_RECLAIM (__GFP_DIRECT_RECLAIM|__GFP_KSWAPD_RECLAIM) + +#define GFP_ATOMIC (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM) +#define GFP_KERNEL (__GFP_RECLAIM | __GFP_IO | __GFP_FS) +#define GFP_NOWAIT (__GFP_KSWAPD_RECLAIM) -#define GFP_ATOMIC (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM) -#define GFP_KERNEL (__GFP_RECLAIM | __GFP_IO | __GFP_FS) static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags) { diff --git a/tools/testing/radix-tree/linux/idr.h b/tools/testing/radix-tree/linux/idr.h new file mode 100644 index 000000000000..4e342f2e37cf --- /dev/null +++ b/tools/testing/radix-tree/linux/idr.h @@ -0,0 +1 @@ +#include "../../../../include/linux/idr.h" diff --git a/tools/testing/radix-tree/linux/kernel.h b/tools/testing/radix-tree/linux/kernel.h index dd1d9aefb14f..63fce553781a 100644 --- a/tools/testing/radix-tree/linux/kernel.h +++ b/tools/testing/radix-tree/linux/kernel.h @@ -20,6 +20,7 @@ #define printk printf #define pr_debug printk +#define pr_cont printk #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) diff --git a/tools/testing/radix-tree/main.c b/tools/testing/radix-tree/main.c index f7e9801a6754..ddd90a11db3f 100644 --- a/tools/testing/radix-tree/main.c +++ b/tools/testing/radix-tree/main.c @@ -3,6 +3,7 @@ #include #include #include +#include #include #include @@ -314,6 +315,11 @@ static void single_thread_tests(bool long_run) rcu_barrier(); printf("after dynamic_height_check: %d allocated, preempt %d\n", nr_allocated, preempt_count); + idr_checks(); + ida_checks(); + rcu_barrier(); + printf("after idr_checks: %d allocated, preempt %d\n", + nr_allocated, preempt_count); big_gang_check(long_run); rcu_barrier(); printf("after big_gang_check: %d allocated, preempt %d\n", diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h index 056a23b56467..b30e11d9d271 100644 --- a/tools/testing/radix-tree/test.h +++ b/tools/testing/radix-tree/test.h @@ -34,6 +34,8 @@ void tag_check(void); void multiorder_checks(void); void iteration_test(unsigned order, unsigned duration); void benchmark(void); +void idr_checks(void); +void ida_checks(void); struct item * item_tag_set(struct radix_tree_root *root, unsigned long index, int tag); -- cgit v1.2.3 From 7ad3d4d85c7af9632055a6ac0aa15b6b6a321c6b Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 16 Dec 2016 11:55:56 -0500 Subject: ida: Move ida_bitmap to a percpu variable When we preload the IDA, we allocate an IDA bitmap. Instead of storing that preallocated bitmap in the IDA, we store it in a percpu variable. Generally there are more IDAs in the system than CPUs, so this cuts down on the number of preallocated bitmaps that are unused, and about half of the IDA users did not call ida_destroy() so they were leaking IDA bitmaps. Signed-off-by: Matthew Wilcox --- include/linux/idr.h | 5 ++-- lib/idr.c | 39 ++-------------------------- lib/radix-tree.c | 45 ++++++++++++++++++++++++++++++--- tools/testing/radix-tree/linux/kernel.h | 2 -- tools/testing/radix-tree/linux/percpu.h | 5 +++- 5 files changed, 51 insertions(+), 45 deletions(-) (limited to 'lib') diff --git a/include/linux/idr.h b/include/linux/idr.h index f58c0a3addc3..2027c7aba50d 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -14,6 +14,7 @@ #include #include +#include struct idr { struct radix_tree_root idr_rt; @@ -171,9 +172,10 @@ struct ida_bitmap { unsigned long bitmap[IDA_BITMAP_LONGS]; }; +DECLARE_PER_CPU(struct ida_bitmap *, ida_bitmap); + struct ida { struct radix_tree_root ida_rt; - struct ida_bitmap *free_bitmap; }; #define IDA_INIT { \ @@ -193,7 +195,6 @@ void ida_simple_remove(struct ida *ida, unsigned int id); static inline void ida_init(struct ida *ida) { INIT_RADIX_TREE(&ida->ida_rt, IDR_RT_MARKER | GFP_NOWAIT); - ida->free_bitmap = NULL; } /** diff --git a/lib/idr.c b/lib/idr.c index b87056e2cc4c..2abd7769c430 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -4,6 +4,7 @@ #include #include +DEFINE_PER_CPU(struct ida_bitmap *, ida_bitmap); static DEFINE_SPINLOCK(simple_ida_lock); /** @@ -193,38 +194,6 @@ EXPORT_SYMBOL(idr_replace); * limitation, it should be quite straightforward to raise the maximum. */ -/** - * ida_pre_get - reserve resources for ida allocation - * @ida: ida handle - * @gfp: memory allocation flags - * - * This function should be called before calling ida_get_new_above(). If it - * is unable to allocate memory, it will return %0. On success, it returns %1. - */ -int ida_pre_get(struct ida *ida, gfp_t gfp) -{ - struct ida_bitmap *bitmap; - - /* - * This looks weird, but the IDA API has no preload_end() equivalent. - * Instead, ida_get_new() can return -EAGAIN, prompting the caller - * to return to the ida_pre_get() step. - */ - idr_preload(gfp); - idr_preload_end(); - - if (!ida->free_bitmap) { - bitmap = kmalloc(sizeof(struct ida_bitmap), gfp); - if (!bitmap) - return 0; - bitmap = xchg(&ida->free_bitmap, bitmap); - kfree(bitmap); - } - - return 1; -} -EXPORT_SYMBOL(ida_pre_get); - #define IDA_MAX (0x80000000U / IDA_BITMAP_BITS) /** @@ -292,10 +261,9 @@ int ida_get_new_above(struct ida *ida, int start, int *id) new += bit; if (new < 0) return -ENOSPC; - bitmap = ida->free_bitmap; + bitmap = this_cpu_xchg(ida_bitmap, NULL); if (!bitmap) return -EAGAIN; - ida->free_bitmap = NULL; memset(bitmap, 0, sizeof(*bitmap)); __set_bit(bit, bitmap->bitmap); radix_tree_iter_replace(root, &iter, slot, bitmap); @@ -361,9 +329,6 @@ void ida_destroy(struct ida *ida) kfree(bitmap); radix_tree_iter_delete(&ida->ida_rt, &iter, slot); } - - kfree(ida->free_bitmap); - ida->free_bitmap = NULL; } EXPORT_SYMBOL(ida_destroy); diff --git a/lib/radix-tree.c b/lib/radix-tree.c index eaea14b8f2ca..7b9f8515033e 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -69,6 +69,14 @@ static struct kmem_cache *radix_tree_node_cachep; RADIX_TREE_MAP_SHIFT)) #define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1) +/* + * The IDA is even shorter since it uses a bitmap at the last level. + */ +#define IDA_INDEX_BITS (8 * sizeof(int) - 1 - ilog2(IDA_BITMAP_BITS)) +#define IDA_MAX_PATH (DIV_ROUND_UP(IDA_INDEX_BITS, \ + RADIX_TREE_MAP_SHIFT)) +#define IDA_PRELOAD_SIZE (IDA_MAX_PATH * 2 - 1) + /* * Per-cpu pool of preloaded nodes */ @@ -346,9 +354,8 @@ static void dump_ida_node(void *entry, unsigned long index) static void ida_dump(struct ida *ida) { struct radix_tree_root *root = &ida->ida_rt; - pr_debug("ida: %p %p free %d bitmap %p\n", ida, root->rnode, - root->gfp_mask >> ROOT_TAG_SHIFT, - ida->free_bitmap); + pr_debug("ida: %p node %p free %d\n", ida, root->rnode, + root->gfp_mask >> ROOT_TAG_SHIFT); dump_ida_node(root->rnode, 0); } #endif @@ -2080,6 +2087,36 @@ void idr_preload(gfp_t gfp_mask) } EXPORT_SYMBOL(idr_preload); +/** + * ida_pre_get - reserve resources for ida allocation + * @ida: ida handle + * @gfp: memory allocation flags + * + * This function should be called before calling ida_get_new_above(). If it + * is unable to allocate memory, it will return %0. On success, it returns %1. + */ +int ida_pre_get(struct ida *ida, gfp_t gfp) +{ + __radix_tree_preload(gfp, IDA_PRELOAD_SIZE); + /* + * The IDA API has no preload_end() equivalent. Instead, + * ida_get_new() can return -EAGAIN, prompting the caller + * to return to the ida_pre_get() step. + */ + preempt_enable(); + + if (!this_cpu_read(ida_bitmap)) { + struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp); + if (!bitmap) + return 0; + bitmap = this_cpu_cmpxchg(ida_bitmap, NULL, bitmap); + kfree(bitmap); + } + + return 1; +} +EXPORT_SYMBOL(ida_pre_get); + void **idr_get_free(struct radix_tree_root *root, struct radix_tree_iter *iter, gfp_t gfp, int end) { @@ -2219,6 +2256,8 @@ static int radix_tree_cpu_dead(unsigned int cpu) kmem_cache_free(radix_tree_node_cachep, node); rtp->nr--; } + kfree(per_cpu(ida_bitmap, cpu)); + per_cpu(ida_bitmap, cpu) = NULL; return 0; } diff --git a/tools/testing/radix-tree/linux/kernel.h b/tools/testing/radix-tree/linux/kernel.h index 63fce553781a..677b8c0f60f9 100644 --- a/tools/testing/radix-tree/linux/kernel.h +++ b/tools/testing/radix-tree/linux/kernel.h @@ -24,6 +24,4 @@ #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) -#define xchg(ptr, x) uatomic_xchg(ptr, x) - #endif /* _KERNEL_H */ diff --git a/tools/testing/radix-tree/linux/percpu.h b/tools/testing/radix-tree/linux/percpu.h index 5837f1d56f17..3ea01a1a88c2 100644 --- a/tools/testing/radix-tree/linux/percpu.h +++ b/tools/testing/radix-tree/linux/percpu.h @@ -1,7 +1,10 @@ - +#define DECLARE_PER_CPU(type, val) extern type val #define DEFINE_PER_CPU(type, val) type val #define __get_cpu_var(var) var #define this_cpu_ptr(var) var +#define this_cpu_read(var) var +#define this_cpu_xchg(var, val) uatomic_xchg(&var, val) +#define this_cpu_cmpxchg(var, old, new) uatomic_cmpxchg(&var, old, new) #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) #define per_cpu(var, cpu) (*per_cpu_ptr(&(var), cpu)) -- cgit v1.2.3 From d37cacc5adace7f3e0824e1f559192ad7299d029 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Sat, 17 Dec 2016 08:18:17 -0500 Subject: ida: Use exceptional entries for small IDAs We can use the root entry as a bitmap and save allocating a 128 byte bitmap for an IDA that contains only a few entries (30 on a 32-bit machine, 62 on a 64-bit machine). This costs about 300 bytes of kernel text on x86-64, so as long as 3 IDAs fall into this category, this is a net win for memory consumption. Thanks to Rasmus Villemoes for his work documenting the problem and collecting statistics on IDAs. Signed-off-by: Matthew Wilcox --- lib/idr.c | 87 +++++++++++++++++++++++++++++++--- lib/radix-tree.c | 8 ++++ tools/testing/radix-tree/idr-test.c | 93 ++++++++++++++++++++++++++++++++++++- 3 files changed, 181 insertions(+), 7 deletions(-) (limited to 'lib') diff --git a/lib/idr.c b/lib/idr.c index 2abd7769c430..7d25e240bc5a 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -194,6 +194,39 @@ EXPORT_SYMBOL(idr_replace); * limitation, it should be quite straightforward to raise the maximum. */ +/* + * Developer's notes: + * + * The IDA uses the functionality provided by the IDR & radix tree to store + * bitmaps in each entry. The IDR_FREE tag means there is at least one bit + * free, unlike the IDR where it means at least one entry is free. + * + * I considered telling the radix tree that each slot is an order-10 node + * and storing the bit numbers in the radix tree, but the radix tree can't + * allow a single multiorder entry at index 0, which would significantly + * increase memory consumption for the IDA. So instead we divide the index + * by the number of bits in the leaf bitmap before doing a radix tree lookup. + * + * As an optimisation, if there are only a few low bits set in any given + * leaf, instead of allocating a 128-byte bitmap, we use the 'exceptional + * entry' functionality of the radix tree to store BITS_PER_LONG - 2 bits + * directly in the entry. By being really tricksy, we could store + * BITS_PER_LONG - 1 bits, but there're diminishing returns after optimising + * for 0-3 allocated IDs. + * + * We allow the radix tree 'exceptional' count to get out of date. Nothing + * in the IDA nor the radix tree code checks it. If it becomes important + * to maintain an accurate exceptional count, switch the rcu_assign_pointer() + * calls to radix_tree_iter_replace() which will correct the exceptional + * count. + * + * The IDA always requires a lock to alloc/free. If we add a 'test_bit' + * equivalent, it will still need locking. Going to RCU lookup would require + * using RCU to free bitmaps, and that's not trivial without embedding an + * RCU head in the bitmap, which adds a 2-pointer overhead to each 128-byte + * bitmap, which is excessive. + */ + #define IDA_MAX (0x80000000U / IDA_BITMAP_BITS) /** @@ -221,11 +254,12 @@ int ida_get_new_above(struct ida *ida, int start, int *id) struct radix_tree_iter iter; struct ida_bitmap *bitmap; unsigned long index; - unsigned bit; + unsigned bit, ebit; int new; index = start / IDA_BITMAP_BITS; bit = start % IDA_BITMAP_BITS; + ebit = bit + RADIX_TREE_EXCEPTIONAL_SHIFT; slot = radix_tree_iter_init(&iter, index); for (;;) { @@ -240,10 +274,29 @@ int ida_get_new_above(struct ida *ida, int start, int *id) return PTR_ERR(slot); } } - if (iter.index > index) + if (iter.index > index) { bit = 0; + ebit = RADIX_TREE_EXCEPTIONAL_SHIFT; + } new = iter.index * IDA_BITMAP_BITS; bitmap = rcu_dereference_raw(*slot); + if (radix_tree_exception(bitmap)) { + unsigned long tmp = (unsigned long)bitmap; + ebit = find_next_zero_bit(&tmp, BITS_PER_LONG, ebit); + if (ebit < BITS_PER_LONG) { + tmp |= 1UL << ebit; + rcu_assign_pointer(*slot, (void *)tmp); + *id = new + ebit - RADIX_TREE_EXCEPTIONAL_SHIFT; + return 0; + } + bitmap = this_cpu_xchg(ida_bitmap, NULL); + if (!bitmap) + return -EAGAIN; + memset(bitmap, 0, sizeof(*bitmap)); + bitmap->bitmap[0] = tmp >> RADIX_TREE_EXCEPTIONAL_SHIFT; + rcu_assign_pointer(*slot, bitmap); + } + if (bitmap) { bit = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, bit); @@ -261,6 +314,14 @@ int ida_get_new_above(struct ida *ida, int start, int *id) new += bit; if (new < 0) return -ENOSPC; + if (ebit < BITS_PER_LONG) { + bitmap = (void *)((1UL << ebit) | + RADIX_TREE_EXCEPTIONAL_ENTRY); + radix_tree_iter_replace(root, &iter, slot, + bitmap); + *id = new; + return 0; + } bitmap = this_cpu_xchg(ida_bitmap, NULL); if (!bitmap) return -EAGAIN; @@ -287,6 +348,7 @@ void ida_remove(struct ida *ida, int id) unsigned long index = id / IDA_BITMAP_BITS; unsigned offset = id % IDA_BITMAP_BITS; struct ida_bitmap *bitmap; + unsigned long *btmp; struct radix_tree_iter iter; void **slot; @@ -295,12 +357,24 @@ void ida_remove(struct ida *ida, int id) goto err; bitmap = rcu_dereference_raw(*slot); - if (!test_bit(offset, bitmap->bitmap)) + if (radix_tree_exception(bitmap)) { + btmp = (unsigned long *)slot; + offset += RADIX_TREE_EXCEPTIONAL_SHIFT; + if (offset >= BITS_PER_LONG) + goto err; + } else { + btmp = bitmap->bitmap; + } + if (!test_bit(offset, btmp)) goto err; - __clear_bit(offset, bitmap->bitmap); + __clear_bit(offset, btmp); radix_tree_iter_tag_set(&ida->ida_rt, &iter, IDR_FREE); - if (bitmap_empty(bitmap->bitmap, IDA_BITMAP_BITS)) { + if (radix_tree_exception(bitmap)) { + if (rcu_dereference_raw(*slot) == + (void *)RADIX_TREE_EXCEPTIONAL_ENTRY) + radix_tree_iter_delete(&ida->ida_rt, &iter, slot); + } else if (bitmap_empty(btmp, IDA_BITMAP_BITS)) { kfree(bitmap); radix_tree_iter_delete(&ida->ida_rt, &iter, slot); } @@ -326,7 +400,8 @@ void ida_destroy(struct ida *ida) radix_tree_for_each_slot(slot, &ida->ida_rt, &iter, 0) { struct ida_bitmap *bitmap = rcu_dereference_raw(*slot); - kfree(bitmap); + if (!radix_tree_exception(bitmap)) + kfree(bitmap); radix_tree_iter_delete(&ida->ida_rt, &iter, slot); } } diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 7b9f8515033e..14130ab197c0 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -338,6 +338,14 @@ static void dump_ida_node(void *entry, unsigned long index) for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) dump_ida_node(node->slots[i], index | (i << node->shift)); + } else if (radix_tree_exceptional_entry(entry)) { + pr_debug("ida excp: %p offset %d indices %lu-%lu data %lx\n", + entry, (int)(index & RADIX_TREE_MAP_MASK), + index * IDA_BITMAP_BITS, + index * IDA_BITMAP_BITS + BITS_PER_LONG - + RADIX_TREE_EXCEPTIONAL_SHIFT, + (unsigned long)entry >> + RADIX_TREE_EXCEPTIONAL_SHIFT); } else { struct ida_bitmap *bitmap = entry; diff --git a/tools/testing/radix-tree/idr-test.c b/tools/testing/radix-tree/idr-test.c index 4dffad9284e0..59081122c63d 100644 --- a/tools/testing/radix-tree/idr-test.c +++ b/tools/testing/radix-tree/idr-test.c @@ -11,6 +11,7 @@ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. */ +#include #include #include #include @@ -214,7 +215,7 @@ void ida_check_nomem(void) DEFINE_IDA(ida); int id, err; - err = ida_get_new(&ida, &id); + err = ida_get_new_above(&ida, 256, &id); assert(err == -EAGAIN); err = ida_get_new_above(&ida, 1UL << 30, &id); assert(err == -EAGAIN); @@ -246,6 +247,66 @@ void ida_check_leaf(void) assert(ida_is_empty(&ida)); } +/* + * Check handling of conversions between exceptional entries and full bitmaps. + */ +void ida_check_conv(void) +{ + DEFINE_IDA(ida); + int id; + unsigned long i; + + for (i = 0; i < IDA_BITMAP_BITS * 2; i += IDA_BITMAP_BITS) { + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new_above(&ida, i + 1, &id)); + assert(id == i + 1); + assert(!ida_get_new_above(&ida, i + BITS_PER_LONG, &id)); + assert(id == i + BITS_PER_LONG); + ida_remove(&ida, i + 1); + ida_remove(&ida, i + BITS_PER_LONG); + assert(ida_is_empty(&ida)); + } + + assert(ida_pre_get(&ida, GFP_KERNEL)); + + for (i = 0; i < IDA_BITMAP_BITS * 2; i++) { + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new(&ida, &id)); + assert(id == i); + } + + for (i = IDA_BITMAP_BITS * 2; i > 0; i--) { + ida_remove(&ida, i - 1); + } + assert(ida_is_empty(&ida)); + + for (i = 0; i < IDA_BITMAP_BITS + BITS_PER_LONG - 4; i++) { + assert(ida_pre_get(&ida, GFP_KERNEL)); + assert(!ida_get_new(&ida, &id)); + assert(id == i); + } + + for (i = IDA_BITMAP_BITS + BITS_PER_LONG - 4; i > 0; i--) { + ida_remove(&ida, i - 1); + } + assert(ida_is_empty(&ida)); + + radix_tree_cpu_dead(1); + for (i = 0; i < 1000000; i++) { + int err = ida_get_new(&ida, &id); + if (err == -EAGAIN) { + assert((i % IDA_BITMAP_BITS) == (BITS_PER_LONG - 2)); + assert(ida_pre_get(&ida, GFP_KERNEL)); + err = ida_get_new(&ida, &id); + } else { + assert((i % IDA_BITMAP_BITS) != (BITS_PER_LONG - 2)); + } + assert(!err); + assert(id == i); + } + ida_destroy(&ida); +} + /* * Check allocations up to and slightly above the maximum allowed (2^31-1) ID. * Allocating up to 2^31-1 should succeed, and then allocating the next one @@ -273,6 +334,34 @@ void ida_check_max(void) } } +void ida_check_random(void) +{ + DEFINE_IDA(ida); + DECLARE_BITMAP(bitmap, 2048); + int id; + unsigned int i; + time_t s = time(NULL); + + repeat: + memset(bitmap, 0, sizeof(bitmap)); + for (i = 0; i < 100000; i++) { + int i = rand(); + int bit = i & 2047; + if (test_bit(bit, bitmap)) { + __clear_bit(bit, bitmap); + ida_remove(&ida, bit); + } else { + __set_bit(bit, bitmap); + ida_pre_get(&ida, GFP_KERNEL); + assert(!ida_get_new_above(&ida, bit, &id)); + assert(id == bit); + } + } + ida_destroy(&ida); + if (time(NULL) < s + 10) + goto repeat; +} + void ida_checks(void) { DEFINE_IDA(ida); @@ -337,6 +426,8 @@ void ida_checks(void) ida_check_leaf(); ida_check_max(); + ida_check_conv(); + ida_check_random(); radix_tree_cpu_dead(1); } -- cgit v1.2.3 From 1293d5c5f54d5118fbb34fc94e01ba02fcd25fc1 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 16 Jan 2017 16:41:29 -0500 Subject: radix-tree: Chain preallocated nodes through ->parent Chaining through the ->private_data member means we have to zero ->private_data after removing preallocated nodes from the list. We're about to initialise ->parent anyway, so we can avoid zeroing it. Signed-off-by: Matthew Wilcox --- lib/radix-tree.c | 9 ++++----- tools/testing/radix-tree/linux.c | 6 +++--- 2 files changed, 7 insertions(+), 8 deletions(-) (limited to 'lib') diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 14130ab197c0..66c71312c381 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -82,7 +82,7 @@ static struct kmem_cache *radix_tree_node_cachep; */ struct radix_tree_preload { unsigned nr; - /* nodes->private_data points to next preallocated node */ + /* nodes->parent points to next preallocated node */ struct radix_tree_node *nodes; }; static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; @@ -405,8 +405,7 @@ radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent, rtp = this_cpu_ptr(&radix_tree_preloads); if (rtp->nr) { ret = rtp->nodes; - rtp->nodes = ret->private_data; - ret->private_data = NULL; + rtp->nodes = ret->parent; rtp->nr--; } /* @@ -483,7 +482,7 @@ static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) preempt_disable(); rtp = this_cpu_ptr(&radix_tree_preloads); if (rtp->nr < nr) { - node->private_data = rtp->nodes; + node->parent = rtp->nodes; rtp->nodes = node; rtp->nr++; } else { @@ -2260,7 +2259,7 @@ static int radix_tree_cpu_dead(unsigned int cpu) rtp = &per_cpu(radix_tree_preloads, cpu); while (rtp->nr) { node = rtp->nodes; - rtp->nodes = node->private_data; + rtp->nodes = node->parent; kmem_cache_free(radix_tree_node_cachep, node); rtp->nr--; } diff --git a/tools/testing/radix-tree/linux.c b/tools/testing/radix-tree/linux.c index 94bcdb992bbf..cf48c8473f48 100644 --- a/tools/testing/radix-tree/linux.c +++ b/tools/testing/radix-tree/linux.c @@ -35,9 +35,9 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, int flags) if (cachep->nr_objs) { cachep->nr_objs--; node = cachep->objs; - cachep->objs = node->private_data; + cachep->objs = node->parent; pthread_mutex_unlock(&cachep->lock); - node->private_data = NULL; + node->parent = NULL; } else { pthread_mutex_unlock(&cachep->lock); node = malloc(cachep->size); @@ -64,7 +64,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp) } else { struct radix_tree_node *node = objp; cachep->nr_objs++; - node->private_data = cachep->objs; + node->parent = cachep->objs; cachep->objs = node; } pthread_mutex_unlock(&cachep->lock); -- cgit v1.2.3 From d58275bc96ae933b1b3888af80920dd6b020c505 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 16 Jan 2017 17:10:21 -0500 Subject: radix-tree: Store a pointer to the root in each node Instead of having this mysterious private_data in each radix_tree_node, store a pointer to the root, which can be useful for debugging. This also relieves the mm code from the duty of updating it. Acked-by: Johannes Weiner Signed-off-by: Matthew Wilcox --- include/linux/radix-tree.h | 2 +- lib/radix-tree.c | 14 ++++++++------ mm/workingset.c | 6 ++---- 3 files changed, 11 insertions(+), 11 deletions(-) (limited to 'lib') diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 2ba0c1f46c84..d250059bbfa4 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -96,7 +96,7 @@ struct radix_tree_node { unsigned char count; /* Total entry count */ unsigned char exceptional; /* Exceptional entry count */ struct radix_tree_node *parent; /* Used when ascending tree */ - void *private_data; /* For tree user */ + struct radix_tree_root *root; /* The tree we belong to */ union { struct list_head private_list; /* For tree user */ struct rcu_head rcu_head; /* Used when freeing node */ diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 66c71312c381..dcb9a2329e65 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -374,6 +374,7 @@ static void ida_dump(struct ida *ida) */ static struct radix_tree_node * radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent, + struct radix_tree_root *root, unsigned int shift, unsigned int offset, unsigned int count, unsigned int exceptional) { @@ -419,11 +420,12 @@ radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent, out: BUG_ON(radix_tree_is_internal_node(ret)); if (ret) { - ret->parent = parent; ret->shift = shift; ret->offset = offset; ret->count = count; ret->exceptional = exceptional; + ret->parent = parent; + ret->root = root; } return ret; } @@ -631,7 +633,7 @@ static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, do { struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL, - shift, 0, 1, 0); + root, shift, 0, 1, 0); if (!node) return -ENOMEM; @@ -828,7 +830,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, shift -= RADIX_TREE_MAP_SHIFT; if (child == NULL) { /* Have to add a child node. */ - child = radix_tree_node_alloc(gfp, node, shift, + child = radix_tree_node_alloc(gfp, node, root, shift, offset, 0, 0); if (!child) return -ENOMEM; @@ -1330,7 +1332,7 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, for (;;) { if (node->shift > order) { - child = radix_tree_node_alloc(gfp, node, + child = radix_tree_node_alloc(gfp, node, root, node->shift - RADIX_TREE_MAP_SHIFT, offset, 0, 0); if (!child) @@ -2152,8 +2154,8 @@ void **idr_get_free(struct radix_tree_root *root, shift -= RADIX_TREE_MAP_SHIFT; if (child == NULL) { /* Have to add a child node. */ - child = radix_tree_node_alloc(gfp, node, shift, offset, - 0, 0); + child = radix_tree_node_alloc(gfp, node, root, shift, + offset, 0, 0); if (!child) return ERR_PTR(-ENOMEM); all_tag_set(child, IDR_FREE); diff --git a/mm/workingset.c b/mm/workingset.c index abb58ffa3c64..80c913c89f11 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -354,10 +354,8 @@ void workingset_update_node(struct radix_tree_node *node, void *private) * as node->private_list is protected by &mapping->tree_lock. */ if (node->count && node->count == node->exceptional) { - if (list_empty(&node->private_list)) { - node->private_data = mapping; + if (list_empty(&node->private_list)) list_lru_add(&shadow_nodes, &node->private_list); - } } else { if (!list_empty(&node->private_list)) list_lru_del(&shadow_nodes, &node->private_list); @@ -435,7 +433,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item, */ node = container_of(item, struct radix_tree_node, private_list); - mapping = node->private_data; + mapping = container_of(node->root, struct address_space, page_tree); /* Coming from the list, invert the lock order */ if (!spin_trylock(&mapping->tree_lock)) { -- cgit v1.2.3 From f7137f79c57f228321dde2ab4586015504feaaac Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 30 Jan 2017 16:22:30 -0500 Subject: radix_tree_iter_resume: Fix out of bounds error The address sanitizer occasionally finds an out of bounds error while running the test-suite. It turned out to be a read of the pointer immediately next to the tree root, but this out of bounds error could have occurred elsewhere. This happens because radix_tree_iter_resume() dereferences 'slot' before checking whether we've come to the end of the chunk. We can just delete this line; the value was never used. Signed-off-by: Matthew Wilcox --- lib/radix-tree.c | 1 - 1 file changed, 1 deletion(-) (limited to 'lib') diff --git a/lib/radix-tree.c b/lib/radix-tree.c index dcb9a2329e65..c1c079ffadcd 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -1685,7 +1685,6 @@ void **radix_tree_iter_resume(void **slot, struct radix_tree_iter *iter) slot++; iter->index = __radix_tree_iter_add(iter, 1); - node = rcu_dereference_raw(*slot); skip_siblings(&node, slot, iter); iter->next_index = iter->index; iter->tags = 0; -- cgit v1.2.3 From 12320d0ff1c9d5582f5c35e4bb8b9c70c475fd71 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 13 Feb 2017 15:22:48 -0500 Subject: radix-tree: Add rcu_dereference and rcu_assign_pointer calls Some of these have been missing for many years. Others were recently introduced by me. Fortunately, we have tools that help us find such things. Signed-off-by: Matthew Wilcox --- include/linux/radix-tree.h | 2 +- lib/radix-tree.c | 26 +++++++++++++++----------- 2 files changed, 16 insertions(+), 12 deletions(-) (limited to 'lib') diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index d250059bbfa4..0b502de7d23a 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -561,7 +561,7 @@ radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) return NULL; found: - if (unlikely(radix_tree_is_internal_node(*slot))) + if (unlikely(radix_tree_is_internal_node(rcu_dereference_raw(*slot)))) return __radix_tree_next_slot(slot, iter, flags); return slot; } diff --git a/lib/radix-tree.c b/lib/radix-tree.c index c1c079ffadcd..723bebe40eef 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -627,7 +627,7 @@ static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, while (index > shift_maxindex(maxshift)) maxshift += RADIX_TREE_MAP_SHIFT; - slot = root->rnode; + slot = rcu_dereference_raw(root->rnode); if (!slot && (!is_idr(root) || root_tag_get(root, IDR_FREE))) goto out; @@ -678,7 +678,7 @@ static inline bool radix_tree_shrink(struct radix_tree_root *root, bool shrunk = false; for (;;) { - struct radix_tree_node *node = root->rnode; + struct radix_tree_node *node = rcu_dereference_raw(root->rnode); struct radix_tree_node *child; if (!radix_tree_is_internal_node(node)) @@ -692,7 +692,7 @@ static inline bool radix_tree_shrink(struct radix_tree_root *root, */ if (node->count != 1) break; - child = node->slots[0]; + child = rcu_dereference_raw(node->slots[0]); if (!child) break; if (!radix_tree_is_internal_node(child) && node->shift) @@ -755,7 +755,8 @@ static bool delete_node(struct radix_tree_root *root, struct radix_tree_node *parent; if (node->count) { - if (node == entry_to_node(root->rnode)) + if (node_to_entry(node) == + rcu_dereference_raw(root->rnode)) deleted |= radix_tree_shrink(root, update_node, private); return deleted; @@ -823,7 +824,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, if (error < 0) return error; shift = error; - child = root->rnode; + child = rcu_dereference_raw(root->rnode); } while (shift > order) { @@ -868,7 +869,7 @@ static void radix_tree_free_nodes(struct radix_tree_node *node) struct radix_tree_node *child = entry_to_node(node); for (;;) { - void *entry = child->slots[offset]; + void *entry = rcu_dereference_raw(child->slots[offset]); if (radix_tree_is_internal_node(entry) && !is_sibling_entry(child, entry)) { child = entry_to_node(entry); @@ -925,7 +926,7 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot, } for (i = 0; i < n; i++) { - struct radix_tree_node *old = slot[i]; + struct radix_tree_node *old = rcu_dereference_raw(slot[i]); if (i) { rcu_assign_pointer(slot[i], child); for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) @@ -1102,7 +1103,7 @@ static inline void replace_sibling_entries(struct radix_tree_node *node, unsigned offset = get_slot_offset(node, slot) + 1; while (offset < RADIX_TREE_MAP_SIZE) { - if (node->slots[offset] != ptr) + if (rcu_dereference_raw(node->slots[offset]) != ptr) break; if (count < 0) { node->slots[offset] = NULL; @@ -1308,7 +1309,8 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, tags |= 1 << tag; for (end = offset + 1; end < RADIX_TREE_MAP_SIZE; end++) { - if (!is_sibling_entry(parent, parent->slots[end])) + if (!is_sibling_entry(parent, + rcu_dereference_raw(parent->slots[end]))) break; for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) if (tags & (1 << tag)) @@ -1339,7 +1341,8 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, goto nomem; if (node != parent) { node->count++; - node->slots[offset] = node_to_entry(child); + rcu_assign_pointer(node->slots[offset], + node_to_entry(child)); for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) if (tags & (1 << tag)) tag_set(node, tag, offset); @@ -1755,7 +1758,8 @@ void **radix_tree_next_chunk(const struct radix_tree_root *root, offset + 1); else while (++offset < RADIX_TREE_MAP_SIZE) { - void *slot = node->slots[offset]; + void *slot = rcu_dereference_raw( + node->slots[offset]); if (is_sibling_entry(node, slot)) continue; if (slot) -- cgit v1.2.3 From d7b627277b57370223d682cede979a279284b12a Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 13 Feb 2017 15:58:24 -0500 Subject: radix-tree: Fix __rcu annotations Many places were missing __rcu annotations. A few places needed a few lines of explanation about why it was safe to not use RCU accessors. Add a custom CFLAGS setting to the Makefile to ensure that new patches don't miss RCU annotations. Signed-off-by: Matthew Wilcox --- include/linux/radix-tree.h | 110 ++++++++++++++++++++------------------- lib/Makefile | 2 + lib/radix-tree.c | 125 ++++++++++++++++++++++++--------------------- 3 files changed, 122 insertions(+), 115 deletions(-) (limited to 'lib') diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 0b502de7d23a..3e5735064b71 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -221,10 +221,8 @@ static inline unsigned int iter_shift(const struct radix_tree_iter *iter) */ /** - * radix_tree_deref_slot - dereference a slot - * @pslot: pointer to slot, returned by radix_tree_lookup_slot - * Returns: item that was stored in that slot with any direct pointer flag - * removed. + * radix_tree_deref_slot - dereference a slot + * @slot: slot pointer, returned by radix_tree_lookup_slot * * For use with radix_tree_lookup_slot(). Caller must hold tree at least read * locked across slot lookup and dereference. Not required if write lock is @@ -232,26 +230,27 @@ static inline unsigned int iter_shift(const struct radix_tree_iter *iter) * * radix_tree_deref_retry must be used to confirm validity of the pointer if * only the read lock is held. + * + * Return: entry stored in that slot. */ -static inline void *radix_tree_deref_slot(void **pslot) +static inline void *radix_tree_deref_slot(void __rcu **slot) { - return rcu_dereference(*pslot); + return rcu_dereference(*slot); } /** - * radix_tree_deref_slot_protected - dereference a slot without RCU lock but with tree lock held - * @pslot: pointer to slot, returned by radix_tree_lookup_slot - * Returns: item that was stored in that slot with any direct pointer flag - * removed. - * - * Similar to radix_tree_deref_slot but only used during migration when a pages - * mapping is being moved. The caller does not hold the RCU read lock but it - * must hold the tree lock to prevent parallel updates. + * radix_tree_deref_slot_protected - dereference a slot with tree lock held + * @slot: slot pointer, returned by radix_tree_lookup_slot + * + * Similar to radix_tree_deref_slot. The caller does not hold the RCU read + * lock but it must hold the tree lock to prevent parallel updates. + * + * Return: entry stored in that slot. */ -static inline void *radix_tree_deref_slot_protected(void **pslot, +static inline void *radix_tree_deref_slot_protected(void __rcu **slot, spinlock_t *treelock) { - return rcu_dereference_protected(*pslot, lockdep_is_held(treelock)); + return rcu_dereference_protected(*slot, lockdep_is_held(treelock)); } /** @@ -287,9 +286,9 @@ static inline int radix_tree_exception(void *arg) return unlikely((unsigned long)arg & RADIX_TREE_ENTRY_MASK); } -int __radix_tree_create(struct radix_tree_root *root, unsigned long index, +int __radix_tree_create(struct radix_tree_root *, unsigned long index, unsigned order, struct radix_tree_node **nodep, - void ***slotp); + void __rcu ***slotp); int __radix_tree_insert(struct radix_tree_root *, unsigned long index, unsigned order, void *); static inline int radix_tree_insert(struct radix_tree_root *root, @@ -298,42 +297,41 @@ static inline int radix_tree_insert(struct radix_tree_root *root, return __radix_tree_insert(root, index, 0, entry); } void *__radix_tree_lookup(const struct radix_tree_root *, unsigned long index, - struct radix_tree_node **nodep, void ***slotp); + struct radix_tree_node **nodep, void __rcu ***slotp); void *radix_tree_lookup(const struct radix_tree_root *, unsigned long); -void **radix_tree_lookup_slot(const struct radix_tree_root *, unsigned long); +void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *, + unsigned long index); typedef void (*radix_tree_update_node_t)(struct radix_tree_node *, void *); -void __radix_tree_replace(struct radix_tree_root *root, - struct radix_tree_node *node, - void **slot, void *item, +void __radix_tree_replace(struct radix_tree_root *, struct radix_tree_node *, + void __rcu **slot, void *entry, radix_tree_update_node_t update_node, void *private); void radix_tree_iter_replace(struct radix_tree_root *, - const struct radix_tree_iter *, void **slot, void *item); -void radix_tree_replace_slot(struct radix_tree_root *root, - void **slot, void *item); -void __radix_tree_delete_node(struct radix_tree_root *root, - struct radix_tree_node *node, + const struct radix_tree_iter *, void __rcu **slot, void *entry); +void radix_tree_replace_slot(struct radix_tree_root *, + void __rcu **slot, void *entry); +void __radix_tree_delete_node(struct radix_tree_root *, + struct radix_tree_node *, radix_tree_update_node_t update_node, void *private); void radix_tree_iter_delete(struct radix_tree_root *, - struct radix_tree_iter *iter, void **slot); + struct radix_tree_iter *iter, void __rcu **slot); void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *); void *radix_tree_delete(struct radix_tree_root *, unsigned long); -void radix_tree_clear_tags(struct radix_tree_root *root, - struct radix_tree_node *node, - void **slot); +void radix_tree_clear_tags(struct radix_tree_root *, struct radix_tree_node *, + void __rcu **slot); unsigned int radix_tree_gang_lookup(const struct radix_tree_root *, void **results, unsigned long first_index, unsigned int max_items); unsigned int radix_tree_gang_lookup_slot(const struct radix_tree_root *, - void ***results, unsigned long *indices, + void __rcu ***results, unsigned long *indices, unsigned long first_index, unsigned int max_items); int radix_tree_preload(gfp_t gfp_mask); int radix_tree_maybe_preload(gfp_t gfp_mask); int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order); void radix_tree_init(void); -void *radix_tree_tag_set(struct radix_tree_root *root, +void *radix_tree_tag_set(struct radix_tree_root *, unsigned long index, unsigned int tag); -void *radix_tree_tag_clear(struct radix_tree_root *root, +void *radix_tree_tag_clear(struct radix_tree_root *, unsigned long index, unsigned int tag); int radix_tree_tag_get(const struct radix_tree_root *, unsigned long index, unsigned int tag); @@ -341,15 +339,13 @@ void radix_tree_iter_tag_set(struct radix_tree_root *, const struct radix_tree_iter *iter, unsigned int tag); void radix_tree_iter_tag_clear(struct radix_tree_root *, const struct radix_tree_iter *iter, unsigned int tag); -unsigned int -radix_tree_gang_lookup_tag(const struct radix_tree_root *, void **results, - unsigned long first_index, unsigned int max_items, - unsigned int tag); -unsigned int -radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *, void ***results, - unsigned long first_index, unsigned int max_items, - unsigned int tag); -int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag); +unsigned int radix_tree_gang_lookup_tag(const struct radix_tree_root *, + void **results, unsigned long first_index, + unsigned int max_items, unsigned int tag); +unsigned int radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *, + void __rcu ***results, unsigned long first_index, + unsigned int max_items, unsigned int tag); +int radix_tree_tagged(const struct radix_tree_root *, unsigned int tag); static inline void radix_tree_preload_end(void) { @@ -361,7 +357,7 @@ int radix_tree_split(struct radix_tree_root *, unsigned long index, unsigned new_order); int radix_tree_join(struct radix_tree_root *, unsigned long index, unsigned new_order, void *); -void **idr_get_free(struct radix_tree_root *, struct radix_tree_iter *, +void __rcu **idr_get_free(struct radix_tree_root *, struct radix_tree_iter *, gfp_t, int end); enum { @@ -377,7 +373,7 @@ enum { * @start: iteration starting index * Returns: NULL */ -static __always_inline void ** +static __always_inline void __rcu ** radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) { /* @@ -406,7 +402,7 @@ radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) * Also it fills @iter with data about chunk: position in the tree (index), * its end (next_index), and constructs a bit mask for tagged iterating (tags). */ -void **radix_tree_next_chunk(const struct radix_tree_root *, +void __rcu **radix_tree_next_chunk(const struct radix_tree_root *, struct radix_tree_iter *iter, unsigned flags); /** @@ -419,7 +415,8 @@ void **radix_tree_next_chunk(const struct radix_tree_root *, * containing it and updates @iter to describe the entry. If @index is not * present, it returns NULL. */ -static inline void **radix_tree_iter_lookup(const struct radix_tree_root *root, +static inline void __rcu ** +radix_tree_iter_lookup(const struct radix_tree_root *root, struct radix_tree_iter *iter, unsigned long index) { radix_tree_iter_init(iter, index); @@ -436,7 +433,8 @@ static inline void **radix_tree_iter_lookup(const struct radix_tree_root *root, * which is at least @index. If @index is larger than any present entry, this * function returns NULL. The @iter is updated to describe the entry found. */ -static inline void **radix_tree_iter_find(const struct radix_tree_root *root, +static inline void __rcu ** +radix_tree_iter_find(const struct radix_tree_root *root, struct radix_tree_iter *iter, unsigned long index) { radix_tree_iter_init(iter, index); @@ -453,7 +451,7 @@ static inline void **radix_tree_iter_find(const struct radix_tree_root *root, * and continue the iteration. */ static inline __must_check -void **radix_tree_iter_retry(struct radix_tree_iter *iter) +void __rcu **radix_tree_iter_retry(struct radix_tree_iter *iter) { iter->next_index = iter->index; iter->tags = 0; @@ -476,7 +474,7 @@ __radix_tree_iter_add(struct radix_tree_iter *iter, unsigned long slots) * have been invalidated by an insertion or deletion. Call this function * before releasing the lock to continue the iteration from the next index. */ -void **__must_check radix_tree_iter_resume(void **slot, +void __rcu **__must_check radix_tree_iter_resume(void __rcu **slot, struct radix_tree_iter *iter); /** @@ -492,11 +490,11 @@ radix_tree_chunk_size(struct radix_tree_iter *iter) } #ifdef CONFIG_RADIX_TREE_MULTIORDER -void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, - unsigned flags); +void __rcu **__radix_tree_next_slot(void __rcu **slot, + struct radix_tree_iter *iter, unsigned flags); #else /* Can't happen without sibling entries, but the compiler can't tell that */ -static inline void ** __radix_tree_next_slot(void **slot, +static inline void __rcu **__radix_tree_next_slot(void __rcu **slot, struct radix_tree_iter *iter, unsigned flags) { return slot; @@ -522,8 +520,8 @@ static inline void ** __radix_tree_next_slot(void **slot, * b) we are doing non-tagged iteration, and iter->index and iter->next_index * have been set up so that radix_tree_chunk_size() returns 1 or 0. */ -static __always_inline void ** -radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) +static __always_inline void __rcu **radix_tree_next_slot(void __rcu **slot, + struct radix_tree_iter *iter, unsigned flags) { if (flags & RADIX_TREE_ITER_TAGGED) { iter->tags >>= 1; diff --git a/lib/Makefile b/lib/Makefile index bc4073a8cd08..2fc096985b21 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -24,6 +24,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ earlycpio.o seq_buf.o nmi_backtrace.o nodemask.o win_minmax.o +CFLAGS_radix-tree.o += -DCONFIG_SPARSE_RCU_POINTER + lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o lib-$(CONFIG_HAS_DMA) += dma-noop.o diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 723bebe40eef..9c0fa4df736b 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -104,7 +104,7 @@ static inline void *node_to_entry(void *ptr) static inline bool is_sibling_entry(const struct radix_tree_node *parent, void *node) { - void **ptr = node; + void __rcu **ptr = node; return (parent->slots <= ptr) && (ptr < parent->slots + RADIX_TREE_MAP_SIZE); } @@ -116,8 +116,8 @@ bool is_sibling_entry(const struct radix_tree_node *parent, void *node) } #endif -static inline -unsigned long get_slot_offset(const struct radix_tree_node *parent, void **slot) +static inline unsigned long +get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot) { return slot - parent->slots; } @@ -126,12 +126,13 @@ static unsigned int radix_tree_descend(const struct radix_tree_node *parent, struct radix_tree_node **nodep, unsigned long index) { unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK; - void **entry = rcu_dereference_raw(parent->slots[offset]); + void __rcu **entry = rcu_dereference_raw(parent->slots[offset]); #ifdef CONFIG_RADIX_TREE_MULTIORDER if (radix_tree_is_internal_node(entry)) { if (is_sibling_entry(parent, entry)) { - void **sibentry = (void **) entry_to_node(entry); + void __rcu **sibentry; + sibentry = (void __rcu **) entry_to_node(entry); offset = get_slot_offset(parent, sibentry); entry = rcu_dereference_raw(*sibentry); } @@ -618,7 +619,7 @@ static unsigned radix_tree_load_root(const struct radix_tree_root *root, static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, unsigned long index, unsigned int shift) { - struct radix_tree_node *slot; + void *entry; unsigned int maxshift; int tag; @@ -627,8 +628,8 @@ static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, while (index > shift_maxindex(maxshift)) maxshift += RADIX_TREE_MAP_SHIFT; - slot = rcu_dereference_raw(root->rnode); - if (!slot && (!is_idr(root) || root_tag_get(root, IDR_FREE))) + entry = rcu_dereference_raw(root->rnode); + if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE))) goto out; do { @@ -652,15 +653,19 @@ static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, } BUG_ON(shift > BITS_PER_LONG); - if (radix_tree_is_internal_node(slot)) { - entry_to_node(slot)->parent = node; - } else if (radix_tree_exceptional_entry(slot)) { + if (radix_tree_is_internal_node(entry)) { + entry_to_node(entry)->parent = node; + } else if (radix_tree_exceptional_entry(entry)) { /* Moving an exceptional root->rnode to a node */ node->exceptional = 1; } - node->slots[0] = slot; - slot = node_to_entry(node); - rcu_assign_pointer(root->rnode, slot); + /* + * entry was already in the radix tree, so we do not need + * rcu_assign_pointer here + */ + node->slots[0] = (void __rcu *)entry; + entry = node_to_entry(node); + rcu_assign_pointer(root->rnode, entry); shift += RADIX_TREE_MAP_SHIFT; } while (shift <= maxshift); out: @@ -708,7 +713,7 @@ static inline bool radix_tree_shrink(struct radix_tree_root *root, * (node->slots[0]), it will be safe to dereference the new * one (root->rnode) as far as dependent read barriers go. */ - root->rnode = child; + root->rnode = (void __rcu *)child; if (is_idr(root) && !tag_get(node, IDR_FREE, 0)) root_tag_clear(root, IDR_FREE); @@ -732,7 +737,7 @@ static inline bool radix_tree_shrink(struct radix_tree_root *root, */ node->count = 0; if (!radix_tree_is_internal_node(child)) { - node->slots[0] = RADIX_TREE_RETRY; + node->slots[0] = (void __rcu *)RADIX_TREE_RETRY; if (update_node) update_node(node, private); } @@ -805,10 +810,10 @@ static bool delete_node(struct radix_tree_root *root, */ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, unsigned order, struct radix_tree_node **nodep, - void ***slotp) + void __rcu ***slotp) { struct radix_tree_node *node = NULL, *child; - void **slot = (void **)&root->rnode; + void __rcu **slot = (void __rcu **)&root->rnode; unsigned long maxindex; unsigned int shift, offset = 0; unsigned long max = index | ((1UL << order) - 1); @@ -890,8 +895,8 @@ static void radix_tree_free_nodes(struct radix_tree_node *node) } #ifdef CONFIG_RADIX_TREE_MULTIORDER -static inline int insert_entries(struct radix_tree_node *node, void **slot, - void *item, unsigned order, bool replace) +static inline int insert_entries(struct radix_tree_node *node, + void __rcu **slot, void *item, unsigned order, bool replace) { struct radix_tree_node *child; unsigned i, n, tag, offset, tags = 0; @@ -953,8 +958,8 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot, return n; } #else -static inline int insert_entries(struct radix_tree_node *node, void **slot, - void *item, unsigned order, bool replace) +static inline int insert_entries(struct radix_tree_node *node, + void __rcu **slot, void *item, unsigned order, bool replace) { if (*slot) return -EEXIST; @@ -981,7 +986,7 @@ int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, unsigned order, void *item) { struct radix_tree_node *node; - void **slot; + void __rcu **slot; int error; BUG_ON(radix_tree_is_internal_node(item)); @@ -1023,15 +1028,15 @@ EXPORT_SYMBOL(__radix_tree_insert); */ void *__radix_tree_lookup(const struct radix_tree_root *root, unsigned long index, struct radix_tree_node **nodep, - void ***slotp) + void __rcu ***slotp) { struct radix_tree_node *node, *parent; unsigned long maxindex; - void **slot; + void __rcu **slot; restart: parent = NULL; - slot = (void **)&root->rnode; + slot = (void __rcu **)&root->rnode; radix_tree_load_root(root, &node, &maxindex); if (index > maxindex) return NULL; @@ -1066,10 +1071,10 @@ void *__radix_tree_lookup(const struct radix_tree_root *root, * exclusive from other writers. Any dereference of the slot must be done * using radix_tree_deref_slot. */ -void **radix_tree_lookup_slot(const struct radix_tree_root *root, +void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root, unsigned long index) { - void **slot; + void __rcu **slot; if (!__radix_tree_lookup(root, index, NULL, &slot)) return NULL; @@ -1096,7 +1101,7 @@ void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index) EXPORT_SYMBOL(radix_tree_lookup); static inline void replace_sibling_entries(struct radix_tree_node *node, - void **slot, int count, int exceptional) + void __rcu **slot, int count, int exceptional) { #ifdef CONFIG_RADIX_TREE_MULTIORDER void *ptr = node_to_entry(slot); @@ -1115,8 +1120,8 @@ static inline void replace_sibling_entries(struct radix_tree_node *node, #endif } -static void replace_slot(void **slot, void *item, struct radix_tree_node *node, - int count, int exceptional) +static void replace_slot(void __rcu **slot, void *item, + struct radix_tree_node *node, int count, int exceptional) { if (WARN_ON_ONCE(radix_tree_is_internal_node(item))) return; @@ -1147,7 +1152,7 @@ static bool node_tag_get(const struct radix_tree_root *root, * deleted. */ static int calculate_count(struct radix_tree_root *root, - struct radix_tree_node *node, void **slot, + struct radix_tree_node *node, void __rcu **slot, void *item, void *old) { if (is_idr(root)) { @@ -1175,7 +1180,7 @@ static int calculate_count(struct radix_tree_root *root, */ void __radix_tree_replace(struct radix_tree_root *root, struct radix_tree_node *node, - void **slot, void *item, + void __rcu **slot, void *item, radix_tree_update_node_t update_node, void *private) { void *old = rcu_dereference_raw(*slot); @@ -1188,7 +1193,7 @@ void __radix_tree_replace(struct radix_tree_root *root, * deleting entries, but that needs accounting against the * node unless the slot is root->rnode. */ - WARN_ON_ONCE(!node && (slot != (void **)&root->rnode) && + WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->rnode) && (count || exceptional)); replace_slot(slot, item, node, count, exceptional); @@ -1218,7 +1223,7 @@ void __radix_tree_replace(struct radix_tree_root *root, * radix_tree_iter_replace(). */ void radix_tree_replace_slot(struct radix_tree_root *root, - void **slot, void *item) + void __rcu **slot, void *item) { __radix_tree_replace(root, NULL, slot, item, NULL, NULL); } @@ -1233,7 +1238,8 @@ void radix_tree_replace_slot(struct radix_tree_root *root, * Caller must hold tree write locked across split and replacement. */ void radix_tree_iter_replace(struct radix_tree_root *root, - const struct radix_tree_iter *iter, void **slot, void *item) + const struct radix_tree_iter *iter, + void __rcu **slot, void *item) { __radix_tree_replace(root, iter->node, slot, item, NULL, NULL); } @@ -1257,7 +1263,7 @@ int radix_tree_join(struct radix_tree_root *root, unsigned long index, unsigned order, void *item) { struct radix_tree_node *node; - void **slot; + void __rcu **slot; int error; BUG_ON(radix_tree_is_internal_node(item)); @@ -1292,7 +1298,7 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, unsigned order) { struct radix_tree_node *parent, *node, *child; - void **slot; + void __rcu **slot; unsigned int offset, end; unsigned n, tag, tags = 0; gfp_t gfp = root_gfp_mask(root); @@ -1603,8 +1609,8 @@ static void set_iter_tags(struct radix_tree_iter *iter, } #ifdef CONFIG_RADIX_TREE_MULTIORDER -static void **skip_siblings(struct radix_tree_node **nodep, - void **slot, struct radix_tree_iter *iter) +static void __rcu **skip_siblings(struct radix_tree_node **nodep, + void __rcu **slot, struct radix_tree_iter *iter) { void *sib = node_to_entry(slot - 1); @@ -1621,8 +1627,8 @@ static void **skip_siblings(struct radix_tree_node **nodep, return NULL; } -void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, - unsigned flags) +void __rcu **__radix_tree_next_slot(void __rcu **slot, + struct radix_tree_iter *iter, unsigned flags) { unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; struct radix_tree_node *node = rcu_dereference_raw(*slot); @@ -1675,14 +1681,15 @@ void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, } EXPORT_SYMBOL(__radix_tree_next_slot); #else -static void **skip_siblings(struct radix_tree_node **nodep, - void **slot, struct radix_tree_iter *iter) +static void __rcu **skip_siblings(struct radix_tree_node **nodep, + void __rcu **slot, struct radix_tree_iter *iter) { return slot; } #endif -void **radix_tree_iter_resume(void **slot, struct radix_tree_iter *iter) +void __rcu **radix_tree_iter_resume(void __rcu **slot, + struct radix_tree_iter *iter) { struct radix_tree_node *node; @@ -1703,7 +1710,7 @@ EXPORT_SYMBOL(radix_tree_iter_resume); * @flags: RADIX_TREE_ITER_* flags and tag index * Returns: pointer to chunk first slot, or NULL if iteration is over */ -void **radix_tree_next_chunk(const struct radix_tree_root *root, +void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root, struct radix_tree_iter *iter, unsigned flags) { unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; @@ -1740,7 +1747,7 @@ void **radix_tree_next_chunk(const struct radix_tree_root *root, iter->tags = 1; iter->node = NULL; __set_iter_shift(iter, 0); - return (void **)&root->rnode; + return (void __rcu **)&root->rnode; } do { @@ -1819,7 +1826,7 @@ radix_tree_gang_lookup(const struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items) { struct radix_tree_iter iter; - void **slot; + void __rcu **slot; unsigned int ret = 0; if (unlikely(!max_items)) @@ -1861,11 +1868,11 @@ EXPORT_SYMBOL(radix_tree_gang_lookup); */ unsigned int radix_tree_gang_lookup_slot(const struct radix_tree_root *root, - void ***results, unsigned long *indices, + void __rcu ***results, unsigned long *indices, unsigned long first_index, unsigned int max_items) { struct radix_tree_iter iter; - void **slot; + void __rcu **slot; unsigned int ret = 0; if (unlikely(!max_items)) @@ -1902,7 +1909,7 @@ radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results, unsigned int tag) { struct radix_tree_iter iter; - void **slot; + void __rcu **slot; unsigned int ret = 0; if (unlikely(!max_items)) @@ -1939,11 +1946,11 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_tag); */ unsigned int radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root, - void ***results, unsigned long first_index, + void __rcu ***results, unsigned long first_index, unsigned int max_items, unsigned int tag) { struct radix_tree_iter iter; - void **slot; + void __rcu **slot; unsigned int ret = 0; if (unlikely(!max_items)) @@ -1979,7 +1986,7 @@ void __radix_tree_delete_node(struct radix_tree_root *root, } static bool __radix_tree_delete(struct radix_tree_root *root, - struct radix_tree_node *node, void **slot) + struct radix_tree_node *node, void __rcu **slot) { void *old = rcu_dereference_raw(*slot); int exceptional = radix_tree_exceptional_entry(old) ? -1 : 0; @@ -2009,7 +2016,7 @@ static bool __radix_tree_delete(struct radix_tree_root *root, * which can access this tree. */ void radix_tree_iter_delete(struct radix_tree_root *root, - struct radix_tree_iter *iter, void **slot) + struct radix_tree_iter *iter, void __rcu **slot) { if (__radix_tree_delete(root, iter->node, slot)) iter->index = iter->next_index; @@ -2030,7 +2037,7 @@ void *radix_tree_delete_item(struct radix_tree_root *root, unsigned long index, void *item) { struct radix_tree_node *node = NULL; - void **slot; + void __rcu **slot; void *entry; entry = __radix_tree_lookup(root, index, &node, &slot); @@ -2064,7 +2071,7 @@ EXPORT_SYMBOL(radix_tree_delete); void radix_tree_clear_tags(struct radix_tree_root *root, struct radix_tree_node *node, - void **slot) + void __rcu **slot) { if (node) { unsigned int tag, offset = get_slot_offset(node, slot); @@ -2129,11 +2136,11 @@ int ida_pre_get(struct ida *ida, gfp_t gfp) } EXPORT_SYMBOL(ida_pre_get); -void **idr_get_free(struct radix_tree_root *root, +void __rcu **idr_get_free(struct radix_tree_root *root, struct radix_tree_iter *iter, gfp_t gfp, int end) { struct radix_tree_node *node = NULL, *child; - void **slot = (void **)&root->rnode; + void __rcu **slot = (void __rcu **)&root->rnode; unsigned long maxindex, start = iter->next_index; unsigned long max = end > 0 ? end - 1 : INT_MAX; unsigned int shift, offset = 0; -- cgit v1.2.3 From 7e73eb0b2df5e8d7bd00a3c5980ab86619699963 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 13 Feb 2017 16:03:55 -0500 Subject: idr: Add missing __rcu annotations Where we use the radix tree iteration macros, we need to annotate 'slot' with __rcu. Make sure we don't forget any new places in the future with the same CFLAGS check used for radix-tree.c. Signed-off-by: Matthew Wilcox --- lib/Makefile | 1 + lib/idr.c | 14 +++++++------- 2 files changed, 8 insertions(+), 7 deletions(-) (limited to 'lib') diff --git a/lib/Makefile b/lib/Makefile index 2fc096985b21..43a80ec3bd10 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -25,6 +25,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ earlycpio.o seq_buf.o nmi_backtrace.o nodemask.o win_minmax.o CFLAGS_radix-tree.o += -DCONFIG_SPARSE_RCU_POINTER +CFLAGS_idr.o += -DCONFIG_SPARSE_RCU_POINTER lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o diff --git a/lib/idr.c b/lib/idr.c index 7d25e240bc5a..b13682bb0a1c 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -28,7 +28,7 @@ static DEFINE_SPINLOCK(simple_ida_lock); */ int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp) { - void **slot; + void __rcu **slot; struct radix_tree_iter iter; if (WARN_ON_ONCE(start < 0)) @@ -98,7 +98,7 @@ int idr_for_each(const struct idr *idr, int (*fn)(int id, void *p, void *data), void *data) { struct radix_tree_iter iter; - void **slot; + void __rcu **slot; radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, 0) { int ret = fn(iter.index, rcu_dereference_raw(*slot), data); @@ -123,7 +123,7 @@ EXPORT_SYMBOL(idr_for_each); void *idr_get_next(struct idr *idr, int *nextid) { struct radix_tree_iter iter; - void **slot; + void __rcu **slot; slot = radix_tree_iter_find(&idr->idr_rt, &iter, *nextid); if (!slot) @@ -151,7 +151,7 @@ EXPORT_SYMBOL(idr_get_next); void *idr_replace(struct idr *idr, void *ptr, int id) { struct radix_tree_node *node; - void **slot = NULL; + void __rcu **slot = NULL; void *entry; if (WARN_ON_ONCE(id < 0)) @@ -250,7 +250,7 @@ EXPORT_SYMBOL(idr_replace); int ida_get_new_above(struct ida *ida, int start, int *id) { struct radix_tree_root *root = &ida->ida_rt; - void **slot; + void __rcu **slot; struct radix_tree_iter iter; struct ida_bitmap *bitmap; unsigned long index; @@ -350,7 +350,7 @@ void ida_remove(struct ida *ida, int id) struct ida_bitmap *bitmap; unsigned long *btmp; struct radix_tree_iter iter; - void **slot; + void __rcu **slot; slot = radix_tree_iter_lookup(&ida->ida_rt, &iter, index); if (!slot) @@ -396,7 +396,7 @@ EXPORT_SYMBOL(ida_remove); void ida_destroy(struct ida *ida) { struct radix_tree_iter iter; - void **slot; + void __rcu **slot; radix_tree_for_each_slot(slot, &ida->ida_rt, &iter, 0) { struct ida_bitmap *bitmap = rcu_dereference_raw(*slot); -- cgit v1.2.3