diff options
| -rw-r--r-- | include/linux/rhashtable.h | 5 | ||||
| -rw-r--r-- | lib/rhashtable.c | 42 |
2 files changed, 45 insertions, 2 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 326acd8c2e9f..7b9bd77ed684 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -168,7 +168,12 @@ int rhashtable_shrink(struct rhashtable *ht); void *rhashtable_lookup(struct rhashtable *ht, const void *key); void *rhashtable_lookup_compare(struct rhashtable *ht, const void *key, bool (*compare)(void *, void *), void *arg); + bool rhashtable_lookup_insert(struct rhashtable *ht, struct rhash_head *obj); +bool rhashtable_lookup_compare_insert(struct rhashtable *ht, + struct rhash_head *obj, + bool (*compare)(void *, void *), + void *arg); void rhashtable_destroy(struct rhashtable *ht); diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 8023b554905c..ed6ae1ad304c 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -727,6 +727,43 @@ EXPORT_SYMBOL_GPL(rhashtable_lookup_compare); */ bool rhashtable_lookup_insert(struct rhashtable *ht, struct rhash_head *obj) { + struct rhashtable_compare_arg arg = { + .ht = ht, + .key = rht_obj(ht, obj) + ht->p.key_offset, + }; + + BUG_ON(!ht->p.key_len); + + return rhashtable_lookup_compare_insert(ht, obj, &rhashtable_compare, + &arg); +} +EXPORT_SYMBOL_GPL(rhashtable_lookup_insert); + +/** + * rhashtable_lookup_compare_insert - search and insert object to hash table + * with compare function + * @ht: hash table + * @obj: pointer to hash head inside object + * @compare: compare function, must return true on match + * @arg: argument passed on to compare function + * + * Locks down the bucket chain in both the old and new table if a resize + * is in progress to ensure that writers can't remove from the old table + * and can't insert to the new table during the atomic operation of search + * and insertion. Searches for duplicates in both the old and new table if + * a resize is in progress. + * + * Lookups may occur in parallel with hashtable mutations and resizing. + * + * Will trigger an automatic deferred table resizing if the size grows + * beyond the watermark indicated by grow_decision() which can be passed + * to rhashtable_init(). + */ +bool rhashtable_lookup_compare_insert(struct rhashtable *ht, + struct rhash_head *obj, + bool (*compare)(void *, void *), + void *arg) +{ struct bucket_table *new_tbl, *old_tbl; spinlock_t *new_bucket_lock, *old_bucket_lock; u32 new_hash, old_hash; @@ -747,7 +784,8 @@ bool rhashtable_lookup_insert(struct rhashtable *ht, struct rhash_head *obj) if (unlikely(old_tbl != new_tbl)) spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED); - if (rhashtable_lookup(ht, rht_obj(ht, obj) + ht->p.key_offset)) { + if (rhashtable_lookup_compare(ht, rht_obj(ht, obj) + ht->p.key_offset, + compare, arg)) { success = false; goto exit; } @@ -763,7 +801,7 @@ exit: return success; } -EXPORT_SYMBOL_GPL(rhashtable_lookup_insert); +EXPORT_SYMBOL_GPL(rhashtable_lookup_compare_insert); static size_t rounded_hashtable_size(struct rhashtable_params *params) { |