From 8d24c0b43125ec26cc80e04588477a9a2afc025c Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Fri, 2 Jan 2015 23:00:14 +0100 Subject: [PATCH] rhashtable: Do hashing inside of rhashtable_lookup_compare() Hash the key inside of rhashtable_lookup_compare() like rhashtable_lookup() does. This allows to simplify the hashing functions and keep them private. Signed-off-by: Thomas Graf Cc: netfilter-devel@vger.kernel.org Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 5 +-- lib/rhashtable.c | 91 +++++++++++++------------------------- net/netfilter/nft_hash.c | 46 ++++++++++++------- net/netlink/af_netlink.c | 5 +-- 4 files changed, 61 insertions(+), 86 deletions(-) diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index b93fd89b2e5e..1b51221c6bbd 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -96,9 +96,6 @@ static inline int lockdep_rht_mutex_is_held(const struct rhashtable *ht) int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params); -u32 rhashtable_hashfn(const struct rhashtable *ht, const void *key, u32 len); -u32 rhashtable_obj_hashfn(const struct rhashtable *ht, void *ptr); - void rhashtable_insert(struct rhashtable *ht, struct rhash_head *node); bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *node); void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj, @@ -111,7 +108,7 @@ int rhashtable_expand(struct rhashtable *ht); int rhashtable_shrink(struct rhashtable *ht); void *rhashtable_lookup(const struct rhashtable *ht, const void *key); -void *rhashtable_lookup_compare(const struct rhashtable *ht, u32 hash, +void *rhashtable_lookup_compare(const struct rhashtable *ht, const void *key, bool (*compare)(void *, void *), void *arg); void rhashtable_destroy(const struct rhashtable *ht); diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 6c3c723e902b..1ee0eb636ca3 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -42,69 +42,39 @@ static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he) return (void *) he - ht->p.head_offset; } -static u32 __hashfn(const struct rhashtable *ht, const void *key, - u32 len, u32 hsize) +static u32 rht_bucket_index(const struct bucket_table *tbl, u32 hash) { - u32 h; - - h = ht->p.hashfn(key, len, ht->p.hash_rnd); - - return h & (hsize - 1); -} - -/** - * rhashtable_hashfn - compute hash for key of given length - * @ht: hash table to compute for - * @key: pointer to key - * @len: length of key - * - * Computes the hash value using the hash function provided in the 'hashfn' - * of struct rhashtable_params. The returned value is guaranteed to be - * smaller than the number of buckets in the hash table. - */ -u32 rhashtable_hashfn(const struct rhashtable *ht, const void *key, u32 len) -{ - struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht); - - return __hashfn(ht, key, len, tbl->size); + return hash & (tbl->size - 1); } -EXPORT_SYMBOL_GPL(rhashtable_hashfn); -static u32 obj_hashfn(const struct rhashtable *ht, const void *ptr, u32 hsize) +static u32 obj_raw_hashfn(const struct rhashtable *ht, const void *ptr) { - if (unlikely(!ht->p.key_len)) { - u32 h; - - h = ht->p.obj_hashfn(ptr, ht->p.hash_rnd); + u32 hash; - return h & (hsize - 1); - } + if (unlikely(!ht->p.key_len)) + hash = ht->p.obj_hashfn(ptr, ht->p.hash_rnd); + else + hash = ht->p.hashfn(ptr + ht->p.key_offset, ht->p.key_len, + ht->p.hash_rnd); - return __hashfn(ht, ptr + ht->p.key_offset, ht->p.key_len, hsize); + return hash; } -/** - * rhashtable_obj_hashfn - compute hash for hashed object - * @ht: hash table to compute for - * @ptr: pointer to hashed object - * - * Computes the hash value using the hash function `hashfn` respectively - * 'obj_hashfn' depending on whether the hash table is set up to work with - * a fixed length key. The returned value is guaranteed to be smaller than - * the number of buckets in the hash table. - */ -u32 rhashtable_obj_hashfn(const struct rhashtable *ht, void *ptr) +static u32 key_hashfn(const struct rhashtable *ht, const void *key, u32 len) { struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht); + u32 hash; + + hash = ht->p.hashfn(key, len, ht->p.hash_rnd); - return obj_hashfn(ht, ptr, tbl->size); + return rht_bucket_index(tbl, hash); } -EXPORT_SYMBOL_GPL(rhashtable_obj_hashfn); static u32 head_hashfn(const struct rhashtable *ht, - const struct rhash_head *he, u32 hsize) + const struct bucket_table *tbl, + const struct rhash_head *he) { - return obj_hashfn(ht, rht_obj(ht, he), hsize); + return rht_bucket_index(tbl, obj_raw_hashfn(ht, rht_obj(ht, he))); } static struct bucket_table *bucket_table_alloc(size_t nbuckets) @@ -170,9 +140,9 @@ static void hashtable_chain_unzip(const struct rhashtable *ht, * reaches a node that doesn't hash to the same bucket as the * previous node p. Call the previous node p; */ - h = head_hashfn(ht, p, new_tbl->size); + h = head_hashfn(ht, new_tbl, p); rht_for_each(he, p->next, ht) { - if (head_hashfn(ht, he, new_tbl->size) != h) + if (head_hashfn(ht, new_tbl, he) != h) break; p = he; } @@ -184,7 +154,7 @@ static void hashtable_chain_unzip(const struct rhashtable *ht, next = NULL; if (he) { rht_for_each(he, he->next, ht) { - if (head_hashfn(ht, he, new_tbl->size) == h) { + if (head_hashfn(ht, new_tbl, he) == h) { next = he; break; } @@ -237,9 +207,9 @@ int rhashtable_expand(struct rhashtable *ht) * single imprecise chain. */ for (i = 0; i < new_tbl->size; i++) { - h = i & (old_tbl->size - 1); + h = rht_bucket_index(old_tbl, i); rht_for_each(he, old_tbl->buckets[h], ht) { - if (head_hashfn(ht, he, new_tbl->size) == i) { + if (head_hashfn(ht, new_tbl, he) == i) { RCU_INIT_POINTER(new_tbl->buckets[i], he); break; } @@ -353,7 +323,7 @@ void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj) ASSERT_RHT_MUTEX(ht); - hash = head_hashfn(ht, obj, tbl->size); + hash = head_hashfn(ht, tbl, obj); RCU_INIT_POINTER(obj->next, tbl->buckets[hash]); rcu_assign_pointer(tbl->buckets[hash], obj); ht->nelems++; @@ -413,7 +383,7 @@ bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj) ASSERT_RHT_MUTEX(ht); - h = head_hashfn(ht, obj, tbl->size); + h = head_hashfn(ht, tbl, obj); pprev = &tbl->buckets[h]; rht_for_each(he, tbl->buckets[h], ht) { @@ -452,7 +422,7 @@ void *rhashtable_lookup(const struct rhashtable *ht, const void *key) BUG_ON(!ht->p.key_len); - h = __hashfn(ht, key, ht->p.key_len, tbl->size); + h = key_hashfn(ht, key, ht->p.key_len); rht_for_each_rcu(he, tbl->buckets[h], ht) { if (memcmp(rht_obj(ht, he) + ht->p.key_offset, key, ht->p.key_len)) @@ -467,7 +437,7 @@ EXPORT_SYMBOL_GPL(rhashtable_lookup); /** * rhashtable_lookup_compare - search hash table with compare function * @ht: hash table - * @hash: hash value of desired entry + * @key: the pointer to the key * @compare: compare function, must return true on match * @arg: argument passed on to compare function * @@ -479,15 +449,14 @@ EXPORT_SYMBOL_GPL(rhashtable_lookup); * * Returns the first entry on which the compare function returned true. */ -void *rhashtable_lookup_compare(const struct rhashtable *ht, u32 hash, +void *rhashtable_lookup_compare(const struct rhashtable *ht, const void *key, bool (*compare)(void *, void *), void *arg) { const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht); struct rhash_head *he; + u32 hash; - if (unlikely(hash >= tbl->size)) - return NULL; - + hash = key_hashfn(ht, key, ht->p.key_len); rht_for_each_rcu(he, tbl->buckets[hash], ht) { if (!compare(rht_obj(ht, he), arg)) continue; diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c index 1e316ce4cb5d..614ee099ba36 100644 --- a/net/netfilter/nft_hash.c +++ b/net/netfilter/nft_hash.c @@ -94,28 +94,40 @@ static void nft_hash_remove(const struct nft_set *set, kfree(he); } +struct nft_compare_arg { + const struct nft_set *set; + struct nft_set_elem *elem; +}; + +static bool nft_hash_compare(void *ptr, void *arg) +{ + struct nft_hash_elem *he = ptr; + struct nft_compare_arg *x = arg; + + if (!nft_data_cmp(&he->key, &x->elem->key, x->set->klen)) { + x->elem->cookie = &he->node; + x->elem->flags = 0; + if (x->set->flags & NFT_SET_MAP) + nft_data_copy(&x->elem->data, he->data); + + return true; + } + + return false; +} + static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem) { const struct rhashtable *priv = nft_set_priv(set); - const struct bucket_table *tbl = rht_dereference_rcu(priv->tbl, priv); - struct rhash_head __rcu * const *pprev; - struct nft_hash_elem *he; - u32 h; - - h = rhashtable_hashfn(priv, &elem->key, set->klen); - pprev = &tbl->buckets[h]; - rht_for_each_entry_rcu(he, tbl->buckets[h], node) { - if (nft_data_cmp(&he->key, &elem->key, set->klen)) { - pprev = &he->node.next; - continue; - } + struct nft_compare_arg arg = { + .set = set, + .elem = elem, + }; - elem->cookie = (void *)pprev; - elem->flags = 0; - if (set->flags & NFT_SET_MAP) - nft_data_copy(&elem->data, he->data); + if (rhashtable_lookup_compare(priv, &elem->key, + &nft_hash_compare, &arg)) return 0; - } + return -ENOENT; } diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 84ea76ca3f1f..a5d7ed627563 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1002,11 +1002,8 @@ static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid, .net = net, .portid = portid, }; - u32 hash; - hash = rhashtable_hashfn(&table->hash, &portid, sizeof(portid)); - - return rhashtable_lookup_compare(&table->hash, hash, + return rhashtable_lookup_compare(&table->hash, &portid, &netlink_compare, &arg); } -- GitLab