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-rw-r--r--lib/rhashtable.c67
1 files changed, 40 insertions, 27 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 0f3be3fad2b2..1c149e9a5cd5 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -386,33 +386,31 @@ static bool rhashtable_check_elasticity(struct rhashtable *ht,
return false;
}
-int rhashtable_insert_rehash(struct rhashtable *ht)
+int rhashtable_insert_rehash(struct rhashtable *ht,
+ struct bucket_table *tbl)
{
struct bucket_table *old_tbl;
struct bucket_table *new_tbl;
- struct bucket_table *tbl;
unsigned int size;
int err;
old_tbl = rht_dereference_rcu(ht->tbl, ht);
- tbl = rhashtable_last_table(ht, old_tbl);
size = tbl->size;
+ err = -EBUSY;
+
if (rht_grow_above_75(ht, tbl))
size *= 2;
/* Do not schedule more than one rehash */
else if (old_tbl != tbl)
- return -EBUSY;
+ goto fail;
+
+ err = -ENOMEM;
new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC);
- if (new_tbl == NULL) {
- /* Schedule async resize/rehash to try allocation
- * non-atomic context.
- */
- schedule_work(&ht->run_work);
- return -ENOMEM;
- }
+ if (new_tbl == NULL)
+ goto fail;
err = rhashtable_rehash_attach(ht, tbl, new_tbl);
if (err) {
@@ -423,12 +421,24 @@ int rhashtable_insert_rehash(struct rhashtable *ht)
schedule_work(&ht->run_work);
return err;
+
+fail:
+ /* Do not fail the insert if someone else did a rehash. */
+ if (likely(rcu_dereference_raw(tbl->future_tbl)))
+ return 0;
+
+ /* Schedule async rehash to retry allocation in process context. */
+ if (err == -ENOMEM)
+ schedule_work(&ht->run_work);
+
+ return err;
}
EXPORT_SYMBOL_GPL(rhashtable_insert_rehash);
-int rhashtable_insert_slow(struct rhashtable *ht, const void *key,
- struct rhash_head *obj,
- struct bucket_table *tbl)
+struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
+ const void *key,
+ struct rhash_head *obj,
+ struct bucket_table *tbl)
{
struct rhash_head *head;
unsigned int hash;
@@ -464,7 +474,12 @@ int rhashtable_insert_slow(struct rhashtable *ht, const void *key,
exit:
spin_unlock(rht_bucket_lock(tbl, hash));
- return err;
+ if (err == 0)
+ return NULL;
+ else if (err == -EAGAIN)
+ return tbl;
+ else
+ return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
@@ -500,10 +515,10 @@ int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter)
if (!iter->walker)
return -ENOMEM;
- mutex_lock(&ht->mutex);
+ spin_lock(&ht->lock);
iter->walker->tbl = rht_dereference(ht->tbl, ht);
list_add(&iter->walker->list, &iter->walker->tbl->walkers);
- mutex_unlock(&ht->mutex);
+ spin_unlock(&ht->lock);
return 0;
}
@@ -517,10 +532,10 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_init);
*/
void rhashtable_walk_exit(struct rhashtable_iter *iter)
{
- mutex_lock(&iter->ht->mutex);
+ spin_lock(&iter->ht->lock);
if (iter->walker->tbl)
list_del(&iter->walker->list);
- mutex_unlock(&iter->ht->mutex);
+ spin_unlock(&iter->ht->lock);
kfree(iter->walker);
}
EXPORT_SYMBOL_GPL(rhashtable_walk_exit);
@@ -544,14 +559,12 @@ int rhashtable_walk_start(struct rhashtable_iter *iter)
{
struct rhashtable *ht = iter->ht;
- mutex_lock(&ht->mutex);
+ rcu_read_lock();
+ spin_lock(&ht->lock);
if (iter->walker->tbl)
list_del(&iter->walker->list);
-
- rcu_read_lock();
-
- mutex_unlock(&ht->mutex);
+ spin_unlock(&ht->lock);
if (!iter->walker->tbl) {
iter->walker->tbl = rht_dereference_rcu(ht->tbl, ht);
@@ -720,9 +733,6 @@ int rhashtable_init(struct rhashtable *ht,
if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT))
return -EINVAL;
- if (params->nelem_hint)
- size = rounded_hashtable_size(params);
-
memset(ht, 0, sizeof(*ht));
mutex_init(&ht->mutex);
spin_lock_init(&ht->lock);
@@ -742,6 +752,9 @@ int rhashtable_init(struct rhashtable *ht,
ht->p.min_size = max(ht->p.min_size, HASH_MIN_SIZE);
+ if (params->nelem_hint)
+ size = rounded_hashtable_size(&ht->p);
+
/* The maximum (not average) chain length grows with the
* size of the hash table, at a rate of (log N)/(log log N).
* The value of 16 is selected so that even if the hash