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-rw-r--r--include/linux/rhashtable.h70
-rw-r--r--lib/rhashtable.c10
2 files changed, 64 insertions, 16 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 3eef0802a0cd..26b7a059c65e 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -343,7 +343,8 @@ int rhashtable_init(struct rhashtable *ht,
struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
const void *key,
struct rhash_head *obj,
- struct bucket_table *old_tbl);
+ struct bucket_table *old_tbl,
+ void **data);
int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl);
int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter,
@@ -563,8 +564,11 @@ restart:
return NULL;
}
-/* Internal function, please use rhashtable_insert_fast() instead */
-static inline int __rhashtable_insert_fast(
+/* Internal function, please use rhashtable_insert_fast() instead. This
+ * function returns the existing element already in hashes in there is a clash,
+ * otherwise it returns an error via ERR_PTR().
+ */
+static inline void *__rhashtable_insert_fast(
struct rhashtable *ht, const void *key, struct rhash_head *obj,
const struct rhashtable_params params)
{
@@ -577,6 +581,7 @@ static inline int __rhashtable_insert_fast(
spinlock_t *lock;
unsigned int elasticity;
unsigned int hash;
+ void *data = NULL;
int err;
restart:
@@ -601,11 +606,14 @@ restart:
new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
if (unlikely(new_tbl)) {
- tbl = rhashtable_insert_slow(ht, key, obj, new_tbl);
+ tbl = rhashtable_insert_slow(ht, key, obj, new_tbl, &data);
if (!IS_ERR_OR_NULL(tbl))
goto slow_path;
err = PTR_ERR(tbl);
+ if (err == -EEXIST)
+ err = 0;
+
goto out;
}
@@ -619,25 +627,25 @@ slow_path:
err = rhashtable_insert_rehash(ht, tbl);
rcu_read_unlock();
if (err)
- return err;
+ return ERR_PTR(err);
goto restart;
}
- err = -EEXIST;
+ err = 0;
elasticity = ht->elasticity;
rht_for_each(head, tbl, hash) {
if (key &&
unlikely(!(params.obj_cmpfn ?
params.obj_cmpfn(&arg, rht_obj(ht, head)) :
- rhashtable_compare(&arg, rht_obj(ht, head)))))
+ rhashtable_compare(&arg, rht_obj(ht, head))))) {
+ data = rht_obj(ht, head);
goto out;
+ }
if (!--elasticity)
goto slow_path;
}
- err = 0;
-
head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
RCU_INIT_POINTER(obj->next, head);
@@ -652,7 +660,7 @@ out:
spin_unlock_bh(lock);
rcu_read_unlock();
- return err;
+ return err ? ERR_PTR(err) : data;
}
/**
@@ -675,7 +683,13 @@ static inline int rhashtable_insert_fast(
struct rhashtable *ht, struct rhash_head *obj,
const struct rhashtable_params params)
{
- return __rhashtable_insert_fast(ht, NULL, obj, params);
+ void *ret;
+
+ ret = __rhashtable_insert_fast(ht, NULL, obj, params);
+ if (IS_ERR(ret))
+ return PTR_ERR(ret);
+
+ return ret == NULL ? 0 : -EEXIST;
}
/**
@@ -704,11 +718,15 @@ static inline int rhashtable_lookup_insert_fast(
const struct rhashtable_params params)
{
const char *key = rht_obj(ht, obj);
+ void *ret;
BUG_ON(ht->p.obj_hashfn);
- return __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj,
- params);
+ ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params);
+ if (IS_ERR(ret))
+ return PTR_ERR(ret);
+
+ return ret == NULL ? 0 : -EEXIST;
}
/**
@@ -737,6 +755,32 @@ static inline int rhashtable_lookup_insert_key(
struct rhashtable *ht, const void *key, struct rhash_head *obj,
const struct rhashtable_params params)
{
+ void *ret;
+
+ BUG_ON(!ht->p.obj_hashfn || !key);
+
+ ret = __rhashtable_insert_fast(ht, key, obj, params);
+ if (IS_ERR(ret))
+ return PTR_ERR(ret);
+
+ return ret == NULL ? 0 : -EEXIST;
+}
+
+/**
+ * rhashtable_lookup_get_insert_key - lookup and insert object into hash table
+ * @ht: hash table
+ * @obj: pointer to hash head inside object
+ * @params: hash table parameters
+ * @data: pointer to element data already in hashes
+ *
+ * Just like rhashtable_lookup_insert_key(), but this function returns the
+ * object if it exists, NULL if it does not and the insertion was successful,
+ * and an ERR_PTR otherwise.
+ */
+static inline void *rhashtable_lookup_get_insert_key(
+ struct rhashtable *ht, const void *key, struct rhash_head *obj,
+ const struct rhashtable_params params)
+{
BUG_ON(!ht->p.obj_hashfn || !key);
return __rhashtable_insert_fast(ht, key, obj, params);
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 5d845ffd7982..7a940d92f17e 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -438,7 +438,8 @@ EXPORT_SYMBOL_GPL(rhashtable_insert_rehash);
struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
const void *key,
struct rhash_head *obj,
- struct bucket_table *tbl)
+ struct bucket_table *tbl,
+ void **data)
{
struct rhash_head *head;
unsigned int hash;
@@ -449,8 +450,11 @@ struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING);
err = -EEXIST;
- if (key && rhashtable_lookup_fast(ht, key, ht->p))
- goto exit;
+ if (key) {
+ *data = rhashtable_lookup_fast(ht, key, ht->p);
+ if (*data)
+ goto exit;
+ }
err = -E2BIG;
if (unlikely(rht_grow_above_max(ht, tbl)))