diff options
| -rw-r--r-- | include/linux/rhashtable.h | 4 | ||||
| -rw-r--r-- | lib/rhashtable.c | 24 |
2 files changed, 17 insertions, 11 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index d438eeb08bff..5ef8ea551556 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -49,12 +49,14 @@ struct rhash_head { /** * struct bucket_table - Table of hash buckets * @size: Number of hash buckets + * @hash_rnd: Random seed to fold into hash * @locks_mask: Mask to apply before accessing locks[] * @locks: Array of spinlocks protecting individual buckets * @buckets: size * hash buckets */ struct bucket_table { size_t size; + u32 hash_rnd; unsigned int locks_mask; spinlock_t *locks; @@ -72,7 +74,6 @@ struct rhashtable; * @key_len: Length of key * @key_offset: Offset of key in struct to be hashed * @head_offset: Offset of rhash_head in struct to be hashed - * @hash_rnd: Seed to use while hashing * @max_shift: Maximum number of shifts while expanding * @min_shift: Minimum number of shifts while shrinking * @nulls_base: Base value to generate nulls marker @@ -85,7 +86,6 @@ struct rhashtable_params { size_t key_len; size_t key_offset; size_t head_offset; - u32 hash_rnd; size_t max_shift; size_t min_shift; u32 nulls_base; diff --git a/lib/rhashtable.c b/lib/rhashtable.c index b5344ef4c684..ba15dceee27f 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -66,25 +66,28 @@ static u32 rht_bucket_index(const struct bucket_table *tbl, u32 hash) return hash & (tbl->size - 1); } -static u32 obj_raw_hashfn(const struct rhashtable *ht, const void *ptr) +static u32 obj_raw_hashfn(struct rhashtable *ht, const void *ptr) { + struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht); u32 hash; if (unlikely(!ht->p.key_len)) - hash = ht->p.obj_hashfn(ptr, ht->p.hash_rnd); + hash = ht->p.obj_hashfn(ptr, tbl->hash_rnd); else hash = ht->p.hashfn(ptr + ht->p.key_offset, ht->p.key_len, - ht->p.hash_rnd); + tbl->hash_rnd); return hash >> HASH_RESERVED_SPACE; } static u32 key_hashfn(struct rhashtable *ht, const void *key, u32 len) { - return ht->p.hashfn(key, len, ht->p.hash_rnd) >> HASH_RESERVED_SPACE; + struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht); + + return ht->p.hashfn(key, len, tbl->hash_rnd) >> HASH_RESERVED_SPACE; } -static u32 head_hashfn(const struct rhashtable *ht, +static u32 head_hashfn(struct rhashtable *ht, const struct bucket_table *tbl, const struct rhash_head *he) { @@ -92,7 +95,7 @@ static u32 head_hashfn(const struct rhashtable *ht, } #ifdef CONFIG_PROVE_LOCKING -static void debug_dump_buckets(const struct rhashtable *ht, +static void debug_dump_buckets(struct rhashtable *ht, const struct bucket_table *tbl) { struct rhash_head *he; @@ -385,6 +388,8 @@ int rhashtable_expand(struct rhashtable *ht) if (new_tbl == NULL) return -ENOMEM; + new_tbl->hash_rnd = old_tbl->hash_rnd; + atomic_inc(&ht->shift); /* Make insertions go into the new, empty table right away. Deletions @@ -476,6 +481,8 @@ int rhashtable_shrink(struct rhashtable *ht) if (new_tbl == NULL) return -ENOMEM; + new_tbl->hash_rnd = tbl->hash_rnd; + rcu_assign_pointer(ht->future_tbl, new_tbl); synchronize_rcu(); @@ -1099,14 +1106,13 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) if (tbl == NULL) return -ENOMEM; + get_random_bytes(&tbl->hash_rnd, sizeof(tbl->hash_rnd)); + atomic_set(&ht->nelems, 0); atomic_set(&ht->shift, ilog2(tbl->size)); RCU_INIT_POINTER(ht->tbl, tbl); RCU_INIT_POINTER(ht->future_tbl, tbl); - if (!ht->p.hash_rnd) - get_random_bytes(&ht->p.hash_rnd, sizeof(ht->p.hash_rnd)); - INIT_WORK(&ht->run_work, rht_deferred_worker); return 0; |