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author | Thomas Graf <tgraf@suug.ch> | 2015-01-03 01:00:14 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2015-01-03 22:32:56 +0300 |
commit | 8d24c0b43125ec26cc80e04588477a9a2afc025c (patch) | |
tree | d02e1b74bf49017dd4fecdeaf82a1e4f8f64a25d /lib/rhashtable.c | |
parent | dd9553988879a3ff71a86323b88409e7631c4e5d (diff) | |
download | linux-8d24c0b43125ec26cc80e04588477a9a2afc025c.tar.xz |
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 <tgraf@suug.ch>
Cc: netfilter-devel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib/rhashtable.c')
-rw-r--r-- | lib/rhashtable.c | 91 |
1 files changed, 30 insertions, 61 deletions
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; |