Commit 8d24c0b4 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

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: default avatarThomas Graf <tgraf@suug.ch>
Cc: netfilter-devel@vger.kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent dd955398

include/linux/rhashtable.h

+1 −4
Original line number Diff line number Diff line
@@ -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);

lib/rhashtable.c

+30 −61
Original line number Diff line number Diff line
@@ -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;

net/netfilter/nft_hash.c

+29 −17
Original line number Diff line number Diff line
@@ -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;

}

net/netlink/af_netlink.c

+1 −4
Original line number Diff line number Diff line
@@ -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);

}

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