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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-03 13:08:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-03 13:08:04 -0700
commit9bd42183b951051f73de121f7ee17091e7d26fbb (patch)
treec85c680126a0548a3c5f083e35f5b1cadce636f6 /kernel/sched/wait.c
parent7447d56217e215e50317f308aee1ed293ac4f749 (diff)
parent72298e5c92c50edd8cb7cfda4519483ce65fa166 (diff)
downloadlinux-0-day-9bd42183b951051f73de121f7ee17091e7d26fbb.tar.gz
linux-0-day-9bd42183b951051f73de121f7ee17091e7d26fbb.tar.xz
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar: "The main changes in this cycle were: - Add the SYSTEM_SCHEDULING bootup state to move various scheduler debug checks earlier into the bootup. This turns silent and sporadically deadly bugs into nice, deterministic splats. Fix some of the splats that triggered. (Thomas Gleixner) - A round of restructuring and refactoring of the load-balancing and topology code (Peter Zijlstra) - Another round of consolidating ~20 of incremental scheduler code history: this time in terms of wait-queue nomenclature. (I didn't get much feedback on these renaming patches, and we can still easily change any names I might have misplaced, so if anyone hates a new name, please holler and I'll fix it.) (Ingo Molnar) - sched/numa improvements, fixes and updates (Rik van Riel) - Another round of x86/tsc scheduler clock code improvements, in hope of making it more robust (Peter Zijlstra) - Improve NOHZ behavior (Frederic Weisbecker) - Deadline scheduler improvements and fixes (Luca Abeni, Daniel Bristot de Oliveira) - Simplify and optimize the topology setup code (Lauro Ramos Venancio) - Debloat and decouple scheduler code some more (Nicolas Pitre) - Simplify code by making better use of llist primitives (Byungchul Park) - ... plus other fixes and improvements" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits) sched/cputime: Refactor the cputime_adjust() code sched/debug: Expose the number of RT/DL tasks that can migrate sched/numa: Hide numa_wake_affine() from UP build sched/fair: Remove effective_load() sched/numa: Implement NUMA node level wake_affine() sched/fair: Simplify wake_affine() for the single socket case sched/numa: Override part of migrate_degrades_locality() when idle balancing sched/rt: Move RT related code from sched/core.c to sched/rt.c sched/deadline: Move DL related code from sched/core.c to sched/deadline.c sched/cpuset: Only offer CONFIG_CPUSETS if SMP is enabled sched/fair: Spare idle load balancing on nohz_full CPUs nohz: Move idle balancer registration to the idle path sched/loadavg: Generalize "_idle" naming to "_nohz" sched/core: Drop the unused try_get_task_struct() helper function sched/fair: WARN() and refuse to set buddy when !se->on_rq sched/debug: Fix SCHED_WARN_ON() to return a value on !CONFIG_SCHED_DEBUG as well sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming sched/wait: Move bit_wait_table[] and related functionality from sched/core.c to sched/wait_bit.c sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into <linux/wait_bit.h> sched/wait: Re-adjust macro line continuation backslashes in <linux/wait.h> ...
Diffstat (limited to 'kernel/sched/wait.c')
-rw-r--r--kernel/sched/wait.c441
1 files changed, 91 insertions, 350 deletions
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index b8c84c6dee64b..17f11c6b0a9f7 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -12,44 +12,44 @@
#include <linux/hash.h>
#include <linux/kthread.h>
-void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *key)
+void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *key)
{
- spin_lock_init(&q->lock);
- lockdep_set_class_and_name(&q->lock, key, name);
- INIT_LIST_HEAD(&q->task_list);
+ spin_lock_init(&wq_head->lock);
+ lockdep_set_class_and_name(&wq_head->lock, key, name);
+ INIT_LIST_HEAD(&wq_head->head);
}
EXPORT_SYMBOL(__init_waitqueue_head);
-void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
+void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
{
unsigned long flags;
- wait->flags &= ~WQ_FLAG_EXCLUSIVE;
- spin_lock_irqsave(&q->lock, flags);
- __add_wait_queue(q, wait);
- spin_unlock_irqrestore(&q->lock, flags);
+ wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
+ spin_lock_irqsave(&wq_head->lock, flags);
+ __add_wait_queue_entry_tail(wq_head, wq_entry);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
}
EXPORT_SYMBOL(add_wait_queue);
-void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
+void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
{
unsigned long flags;
- wait->flags |= WQ_FLAG_EXCLUSIVE;
- spin_lock_irqsave(&q->lock, flags);
- __add_wait_queue_tail(q, wait);
- spin_unlock_irqrestore(&q->lock, flags);
+ wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
+ spin_lock_irqsave(&wq_head->lock, flags);
+ __add_wait_queue_entry_tail(wq_head, wq_entry);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
}
EXPORT_SYMBOL(add_wait_queue_exclusive);
-void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
+void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
{
unsigned long flags;
- spin_lock_irqsave(&q->lock, flags);
- __remove_wait_queue(q, wait);
- spin_unlock_irqrestore(&q->lock, flags);
+ spin_lock_irqsave(&wq_head->lock, flags);
+ __remove_wait_queue(wq_head, wq_entry);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
}
EXPORT_SYMBOL(remove_wait_queue);
@@ -63,12 +63,12 @@ EXPORT_SYMBOL(remove_wait_queue);
* started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
* zero in this (rare) case, and we handle it by continuing to scan the queue.
*/
-static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
+static void __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode,
int nr_exclusive, int wake_flags, void *key)
{
- wait_queue_t *curr, *next;
+ wait_queue_entry_t *curr, *next;
- list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
+ list_for_each_entry_safe(curr, next, &wq_head->head, entry) {
unsigned flags = curr->flags;
if (curr->func(curr, mode, wake_flags, key) &&
@@ -79,7 +79,7 @@ static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
/**
* __wake_up - wake up threads blocked on a waitqueue.
- * @q: the waitqueue
+ * @wq_head: the waitqueue
* @mode: which threads
* @nr_exclusive: how many wake-one or wake-many threads to wake up
* @key: is directly passed to the wakeup function
@@ -87,35 +87,35 @@ static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
* It may be assumed that this function implies a write memory barrier before
* changing the task state if and only if any tasks are woken up.
*/
-void __wake_up(wait_queue_head_t *q, unsigned int mode,
+void __wake_up(struct wait_queue_head *wq_head, unsigned int mode,
int nr_exclusive, void *key)
{
unsigned long flags;
- spin_lock_irqsave(&q->lock, flags);
- __wake_up_common(q, mode, nr_exclusive, 0, key);
- spin_unlock_irqrestore(&q->lock, flags);
+ spin_lock_irqsave(&wq_head->lock, flags);
+ __wake_up_common(wq_head, mode, nr_exclusive, 0, key);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
}
EXPORT_SYMBOL(__wake_up);
/*
* Same as __wake_up but called with the spinlock in wait_queue_head_t held.
*/
-void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr)
+void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr)
{
- __wake_up_common(q, mode, nr, 0, NULL);
+ __wake_up_common(wq_head, mode, nr, 0, NULL);
}
EXPORT_SYMBOL_GPL(__wake_up_locked);
-void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
+void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key)
{
- __wake_up_common(q, mode, 1, 0, key);
+ __wake_up_common(wq_head, mode, 1, 0, key);
}
EXPORT_SYMBOL_GPL(__wake_up_locked_key);
/**
* __wake_up_sync_key - wake up threads blocked on a waitqueue.
- * @q: the waitqueue
+ * @wq_head: the waitqueue
* @mode: which threads
* @nr_exclusive: how many wake-one or wake-many threads to wake up
* @key: opaque value to be passed to wakeup targets
@@ -130,30 +130,30 @@ EXPORT_SYMBOL_GPL(__wake_up_locked_key);
* It may be assumed that this function implies a write memory barrier before
* changing the task state if and only if any tasks are woken up.
*/
-void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
+void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode,
int nr_exclusive, void *key)
{
unsigned long flags;
int wake_flags = 1; /* XXX WF_SYNC */
- if (unlikely(!q))
+ if (unlikely(!wq_head))
return;
if (unlikely(nr_exclusive != 1))
wake_flags = 0;
- spin_lock_irqsave(&q->lock, flags);
- __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
- spin_unlock_irqrestore(&q->lock, flags);
+ spin_lock_irqsave(&wq_head->lock, flags);
+ __wake_up_common(wq_head, mode, nr_exclusive, wake_flags, key);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
}
EXPORT_SYMBOL_GPL(__wake_up_sync_key);
/*
* __wake_up_sync - see __wake_up_sync_key()
*/
-void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
+void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr_exclusive)
{
- __wake_up_sync_key(q, mode, nr_exclusive, NULL);
+ __wake_up_sync_key(wq_head, mode, nr_exclusive, NULL);
}
EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
@@ -170,48 +170,48 @@ EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
* loads to move into the critical region).
*/
void
-prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state)
+prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
{
unsigned long flags;
- wait->flags &= ~WQ_FLAG_EXCLUSIVE;
- spin_lock_irqsave(&q->lock, flags);
- if (list_empty(&wait->task_list))
- __add_wait_queue(q, wait);
+ wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
+ spin_lock_irqsave(&wq_head->lock, flags);
+ if (list_empty(&wq_entry->entry))
+ __add_wait_queue(wq_head, wq_entry);
set_current_state(state);
- spin_unlock_irqrestore(&q->lock, flags);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
}
EXPORT_SYMBOL(prepare_to_wait);
void
-prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state)
+prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
{
unsigned long flags;
- wait->flags |= WQ_FLAG_EXCLUSIVE;
- spin_lock_irqsave(&q->lock, flags);
- if (list_empty(&wait->task_list))
- __add_wait_queue_tail(q, wait);
+ wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
+ spin_lock_irqsave(&wq_head->lock, flags);
+ if (list_empty(&wq_entry->entry))
+ __add_wait_queue_entry_tail(wq_head, wq_entry);
set_current_state(state);
- spin_unlock_irqrestore(&q->lock, flags);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
}
EXPORT_SYMBOL(prepare_to_wait_exclusive);
-void init_wait_entry(wait_queue_t *wait, int flags)
+void init_wait_entry(struct wait_queue_entry *wq_entry, int flags)
{
- wait->flags = flags;
- wait->private = current;
- wait->func = autoremove_wake_function;
- INIT_LIST_HEAD(&wait->task_list);
+ wq_entry->flags = flags;
+ wq_entry->private = current;
+ wq_entry->func = autoremove_wake_function;
+ INIT_LIST_HEAD(&wq_entry->entry);
}
EXPORT_SYMBOL(init_wait_entry);
-long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state)
+long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
{
unsigned long flags;
long ret = 0;
- spin_lock_irqsave(&q->lock, flags);
+ spin_lock_irqsave(&wq_head->lock, flags);
if (unlikely(signal_pending_state(state, current))) {
/*
* Exclusive waiter must not fail if it was selected by wakeup,
@@ -219,24 +219,24 @@ long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state)
*
* The caller will recheck the condition and return success if
* we were already woken up, we can not miss the event because
- * wakeup locks/unlocks the same q->lock.
+ * wakeup locks/unlocks the same wq_head->lock.
*
* But we need to ensure that set-condition + wakeup after that
* can't see us, it should wake up another exclusive waiter if
* we fail.
*/
- list_del_init(&wait->task_list);
+ list_del_init(&wq_entry->entry);
ret = -ERESTARTSYS;
} else {
- if (list_empty(&wait->task_list)) {
- if (wait->flags & WQ_FLAG_EXCLUSIVE)
- __add_wait_queue_tail(q, wait);
+ if (list_empty(&wq_entry->entry)) {
+ if (wq_entry->flags & WQ_FLAG_EXCLUSIVE)
+ __add_wait_queue_entry_tail(wq_head, wq_entry);
else
- __add_wait_queue(q, wait);
+ __add_wait_queue(wq_head, wq_entry);
}
set_current_state(state);
}
- spin_unlock_irqrestore(&q->lock, flags);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
return ret;
}
@@ -249,10 +249,10 @@ EXPORT_SYMBOL(prepare_to_wait_event);
* condition in the caller before they add the wait
* entry to the wake queue.
*/
-int do_wait_intr(wait_queue_head_t *wq, wait_queue_t *wait)
+int do_wait_intr(wait_queue_head_t *wq, wait_queue_entry_t *wait)
{
- if (likely(list_empty(&wait->task_list)))
- __add_wait_queue_tail(wq, wait);
+ if (likely(list_empty(&wait->entry)))
+ __add_wait_queue_entry_tail(wq, wait);
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current))
@@ -265,10 +265,10 @@ int do_wait_intr(wait_queue_head_t *wq, wait_queue_t *wait)
}
EXPORT_SYMBOL(do_wait_intr);
-int do_wait_intr_irq(wait_queue_head_t *wq, wait_queue_t *wait)
+int do_wait_intr_irq(wait_queue_head_t *wq, wait_queue_entry_t *wait)
{
- if (likely(list_empty(&wait->task_list)))
- __add_wait_queue_tail(wq, wait);
+ if (likely(list_empty(&wait->entry)))
+ __add_wait_queue_entry_tail(wq, wait);
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current))
@@ -283,14 +283,14 @@ EXPORT_SYMBOL(do_wait_intr_irq);
/**
* finish_wait - clean up after waiting in a queue
- * @q: waitqueue waited on
- * @wait: wait descriptor
+ * @wq_head: waitqueue waited on
+ * @wq_entry: wait descriptor
*
* Sets current thread back to running state and removes
* the wait descriptor from the given waitqueue if still
* queued.
*/
-void finish_wait(wait_queue_head_t *q, wait_queue_t *wait)
+void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
{
unsigned long flags;
@@ -308,20 +308,20 @@ void finish_wait(wait_queue_head_t *q, wait_queue_t *wait)
* have _one_ other CPU that looks at or modifies
* the list).
*/
- if (!list_empty_careful(&wait->task_list)) {
- spin_lock_irqsave(&q->lock, flags);
- list_del_init(&wait->task_list);
- spin_unlock_irqrestore(&q->lock, flags);
+ if (!list_empty_careful(&wq_entry->entry)) {
+ spin_lock_irqsave(&wq_head->lock, flags);
+ list_del_init(&wq_entry->entry);
+ spin_unlock_irqrestore(&wq_head->lock, flags);
}
}
EXPORT_SYMBOL(finish_wait);
-int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key)
+int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key)
{
- int ret = default_wake_function(wait, mode, sync, key);
+ int ret = default_wake_function(wq_entry, mode, sync, key);
if (ret)
- list_del_init(&wait->task_list);
+ list_del_init(&wq_entry->entry);
return ret;
}
EXPORT_SYMBOL(autoremove_wake_function);
@@ -334,24 +334,24 @@ static inline bool is_kthread_should_stop(void)
/*
* DEFINE_WAIT_FUNC(wait, woken_wake_func);
*
- * add_wait_queue(&wq, &wait);
+ * add_wait_queue(&wq_head, &wait);
* for (;;) {
* if (condition)
* break;
*
* p->state = mode; condition = true;
* smp_mb(); // A smp_wmb(); // C
- * if (!wait->flags & WQ_FLAG_WOKEN) wait->flags |= WQ_FLAG_WOKEN;
+ * if (!wq_entry->flags & WQ_FLAG_WOKEN) wq_entry->flags |= WQ_FLAG_WOKEN;
* schedule() try_to_wake_up();
* p->state = TASK_RUNNING; ~~~~~~~~~~~~~~~~~~
- * wait->flags &= ~WQ_FLAG_WOKEN; condition = true;
+ * wq_entry->flags &= ~WQ_FLAG_WOKEN; condition = true;
* smp_mb() // B smp_wmb(); // C
- * wait->flags |= WQ_FLAG_WOKEN;
+ * wq_entry->flags |= WQ_FLAG_WOKEN;
* }
- * remove_wait_queue(&wq, &wait);
+ * remove_wait_queue(&wq_head, &wait);
*
*/
-long wait_woken(wait_queue_t *wait, unsigned mode, long timeout)
+long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout)
{
set_current_state(mode); /* A */
/*
@@ -359,7 +359,7 @@ long wait_woken(wait_queue_t *wait, unsigned mode, long timeout)
* woken_wake_function() such that if we observe WQ_FLAG_WOKEN we must
* also observe all state before the wakeup.
*/
- if (!(wait->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop())
+ if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop())
timeout = schedule_timeout(timeout);
__set_current_state(TASK_RUNNING);
@@ -369,13 +369,13 @@ long wait_woken(wait_queue_t *wait, unsigned mode, long timeout)
* condition being true _OR_ WQ_FLAG_WOKEN such that we will not miss
* an event.
*/
- smp_store_mb(wait->flags, wait->flags & ~WQ_FLAG_WOKEN); /* B */
+ smp_store_mb(wq_entry->flags, wq_entry->flags & ~WQ_FLAG_WOKEN); /* B */
return timeout;
}
EXPORT_SYMBOL(wait_woken);
-int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key)
+int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key)
{
/*
* Although this function is called under waitqueue lock, LOCK
@@ -385,267 +385,8 @@ int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key)
* and is paired with smp_store_mb() in wait_woken().
*/
smp_wmb(); /* C */
- wait->flags |= WQ_FLAG_WOKEN;
+ wq_entry->flags |= WQ_FLAG_WOKEN;
- return default_wake_function(wait, mode, sync, key);
+ return default_wake_function(wq_entry, mode, sync, key);
}
EXPORT_SYMBOL(woken_wake_function);
-
-int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *arg)
-{
- struct wait_bit_key *key = arg;
- struct wait_bit_queue *wait_bit
- = container_of(wait, struct wait_bit_queue, wait);
-
- if (wait_bit->key.flags != key->flags ||
- wait_bit->key.bit_nr != key->bit_nr ||
- test_bit(key->bit_nr, key->flags))
- return 0;
- else
- return autoremove_wake_function(wait, mode, sync, key);
-}
-EXPORT_SYMBOL(wake_bit_function);
-
-/*
- * To allow interruptible waiting and asynchronous (i.e. nonblocking)
- * waiting, the actions of __wait_on_bit() and __wait_on_bit_lock() are
- * permitted return codes. Nonzero return codes halt waiting and return.
- */
-int __sched
-__wait_on_bit(wait_queue_head_t *wq, struct wait_bit_queue *q,
- wait_bit_action_f *action, unsigned mode)
-{
- int ret = 0;
-
- do {
- prepare_to_wait(wq, &q->wait, mode);
- if (test_bit(q->key.bit_nr, q->key.flags))
- ret = (*action)(&q->key, mode);
- } while (test_bit(q->key.bit_nr, q->key.flags) && !ret);
- finish_wait(wq, &q->wait);
- return ret;
-}
-EXPORT_SYMBOL(__wait_on_bit);
-
-int __sched out_of_line_wait_on_bit(void *word, int bit,
- wait_bit_action_f *action, unsigned mode)
-{
- wait_queue_head_t *wq = bit_waitqueue(word, bit);
- DEFINE_WAIT_BIT(wait, word, bit);
-
- return __wait_on_bit(wq, &wait, action, mode);
-}
-EXPORT_SYMBOL(out_of_line_wait_on_bit);
-
-int __sched out_of_line_wait_on_bit_timeout(
- void *word, int bit, wait_bit_action_f *action,
- unsigned mode, unsigned long timeout)
-{
- wait_queue_head_t *wq = bit_waitqueue(word, bit);
- DEFINE_WAIT_BIT(wait, word, bit);
-
- wait.key.timeout = jiffies + timeout;
- return __wait_on_bit(wq, &wait, action, mode);
-}
-EXPORT_SYMBOL_GPL(out_of_line_wait_on_bit_timeout);
-
-int __sched
-__wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
- wait_bit_action_f *action, unsigned mode)
-{
- int ret = 0;
-
- for (;;) {
- prepare_to_wait_exclusive(wq, &q->wait, mode);
- if (test_bit(q->key.bit_nr, q->key.flags)) {
- ret = action(&q->key, mode);
- /*
- * See the comment in prepare_to_wait_event().
- * finish_wait() does not necessarily takes wq->lock,
- * but test_and_set_bit() implies mb() which pairs with
- * smp_mb__after_atomic() before wake_up_page().
- */
- if (ret)
- finish_wait(wq, &q->wait);
- }
- if (!test_and_set_bit(q->key.bit_nr, q->key.flags)) {
- if (!ret)
- finish_wait(wq, &q->wait);
- return 0;
- } else if (ret) {
- return ret;
- }
- }
-}
-EXPORT_SYMBOL(__wait_on_bit_lock);
-
-int __sched out_of_line_wait_on_bit_lock(void *word, int bit,
- wait_bit_action_f *action, unsigned mode)
-{
- wait_queue_head_t *wq = bit_waitqueue(word, bit);
- DEFINE_WAIT_BIT(wait, word, bit);
-
- return __wait_on_bit_lock(wq, &wait, action, mode);
-}
-EXPORT_SYMBOL(out_of_line_wait_on_bit_lock);
-
-void __wake_up_bit(wait_queue_head_t *wq, void *word, int bit)
-{
- struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit);
- if (waitqueue_active(wq))
- __wake_up(wq, TASK_NORMAL, 1, &key);
-}
-EXPORT_SYMBOL(__wake_up_bit);
-
-/**
- * wake_up_bit - wake up a waiter on a bit
- * @word: the word being waited on, a kernel virtual address
- * @bit: the bit of the word being waited on
- *
- * There is a standard hashed waitqueue table for generic use. This
- * is the part of the hashtable's accessor API that wakes up waiters
- * on a bit. For instance, if one were to have waiters on a bitflag,
- * one would call wake_up_bit() after clearing the bit.
- *
- * In order for this to function properly, as it uses waitqueue_active()
- * internally, some kind of memory barrier must be done prior to calling
- * this. Typically, this will be smp_mb__after_atomic(), but in some
- * cases where bitflags are manipulated non-atomically under a lock, one
- * may need to use a less regular barrier, such fs/inode.c's smp_mb(),
- * because spin_unlock() does not guarantee a memory barrier.
- */
-void wake_up_bit(void *word, int bit)
-{
- __wake_up_bit(bit_waitqueue(word, bit), word, bit);
-}
-EXPORT_SYMBOL(wake_up_bit);
-
-/*
- * Manipulate the atomic_t address to produce a better bit waitqueue table hash
- * index (we're keying off bit -1, but that would produce a horrible hash
- * value).
- */
-static inline wait_queue_head_t *atomic_t_waitqueue(atomic_t *p)
-{
- if (BITS_PER_LONG == 64) {
- unsigned long q = (unsigned long)p;
- return bit_waitqueue((void *)(q & ~1), q & 1);
- }
- return bit_waitqueue(p, 0);
-}
-
-static int wake_atomic_t_function(wait_queue_t *wait, unsigned mode, int sync,
- void *arg)
-{
- struct wait_bit_key *key = arg;
- struct wait_bit_queue *wait_bit
- = container_of(wait, struct wait_bit_queue, wait);
- atomic_t *val = key->flags;
-
- if (wait_bit->key.flags != key->flags ||
- wait_bit->key.bit_nr != key->bit_nr ||
- atomic_read(val) != 0)
- return 0;
- return autoremove_wake_function(wait, mode, sync, key);
-}
-
-/*
- * To allow interruptible waiting and asynchronous (i.e. nonblocking) waiting,
- * the actions of __wait_on_atomic_t() are permitted return codes. Nonzero
- * return codes halt waiting and return.
- */
-static __sched
-int __wait_on_atomic_t(wait_queue_head_t *wq, struct wait_bit_queue *q,
- int (*action)(atomic_t *), unsigned mode)
-{
- atomic_t *val;
- int ret = 0;
-
- do {
- prepare_to_wait(wq, &q->wait, mode);
- val = q->key.flags;
- if (atomic_read(val) == 0)
- break;
- ret = (*action)(val);
- } while (!ret && atomic_read(val) != 0);
- finish_wait(wq, &q->wait);
- return ret;
-}
-
-#define DEFINE_WAIT_ATOMIC_T(name, p) \
- struct wait_bit_queue name = { \
- .key = __WAIT_ATOMIC_T_KEY_INITIALIZER(p), \
- .wait = { \
- .private = current, \
- .func = wake_atomic_t_function, \
- .task_list = \
- LIST_HEAD_INIT((name).wait.task_list), \
- }, \
- }
-
-__sched int out_of_line_wait_on_atomic_t(atomic_t *p, int (*action)(atomic_t *),
- unsigned mode)
-{
- wait_queue_head_t *wq = atomic_t_waitqueue(p);
- DEFINE_WAIT_ATOMIC_T(wait, p);
-
- return __wait_on_atomic_t(wq, &wait, action, mode);
-}
-EXPORT_SYMBOL(out_of_line_wait_on_atomic_t);
-
-/**
- * wake_up_atomic_t - Wake up a waiter on a atomic_t
- * @p: The atomic_t being waited on, a kernel virtual address
- *
- * Wake up anyone waiting for the atomic_t to go to zero.
- *
- * Abuse the bit-waker function and its waitqueue hash table set (the atomic_t
- * check is done by the waiter's wake function, not the by the waker itself).
- */
-void wake_up_atomic_t(atomic_t *p)
-{
- __wake_up_bit(atomic_t_waitqueue(p), p, WAIT_ATOMIC_T_BIT_NR);
-}
-EXPORT_SYMBOL(wake_up_atomic_t);
-
-__sched int bit_wait(struct wait_bit_key *word, int mode)
-{
- schedule();
- if (signal_pending_state(mode, current))
- return -EINTR;
- return 0;
-}
-EXPORT_SYMBOL(bit_wait);
-
-__sched int bit_wait_io(struct wait_bit_key *word, int mode)
-{
- io_schedule();
- if (signal_pending_state(mode, current))
- return -EINTR;
- return 0;
-}
-EXPORT_SYMBOL(bit_wait_io);
-
-__sched int bit_wait_timeout(struct wait_bit_key *word, int mode)
-{
- unsigned long now = READ_ONCE(jiffies);
- if (time_after_eq(now, word->timeout))
- return -EAGAIN;
- schedule_timeout(word->timeout - now);
- if (signal_pending_state(mode, current))
- return -EINTR;
- return 0;
-}
-EXPORT_SYMBOL_GPL(bit_wait_timeout);
-
-__sched int bit_wait_io_timeout(struct wait_bit_key *word, int mode)
-{
- unsigned long now = READ_ONCE(jiffies);
- if (time_after_eq(now, word->timeout))
- return -EAGAIN;
- io_schedule_timeout(word->timeout - now);
- if (signal_pending_state(mode, current))
- return -EINTR;
- return 0;
-}
-EXPORT_SYMBOL_GPL(bit_wait_io_timeout);