From cfe4a9dda034e2b5b6ba0b6313b65dfb89ee451c Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Sat, 2 Aug 2014 11:47:46 +0200 Subject: nftables: Convert nft_hash to use generic rhashtable The sizing of the hash table and the practice of requiring a lookup to retrieve the pprev to be stored in the element cookie before the deletion of an entry is left intact. Signed-off-by: Thomas Graf Acked-by: Patrick McHardy Reviewed-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/netfilter/nft_hash.c | 291 +++++++++-------------------------------------- 1 file changed, 55 insertions(+), 236 deletions(-) (limited to 'net') diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c index 4080ed6a072b..28fb8f38e6ba 100644 --- a/net/netfilter/nft_hash.c +++ b/net/netfilter/nft_hash.c @@ -15,209 +15,40 @@ #include #include #include -#include +#include #include #include #include -#define NFT_HASH_MIN_SIZE 4UL - -struct nft_hash { - struct nft_hash_table __rcu *tbl; -}; - -struct nft_hash_table { - unsigned int size; - struct nft_hash_elem __rcu *buckets[]; -}; +/* We target a hash table size of 4, element hint is 75% of final size */ +#define NFT_HASH_ELEMENT_HINT 3 struct nft_hash_elem { - struct nft_hash_elem __rcu *next; + struct rhash_head node; struct nft_data key; struct nft_data data[]; }; -#define nft_hash_for_each_entry(i, head) \ - for (i = nft_dereference(head); i != NULL; i = nft_dereference(i->next)) -#define nft_hash_for_each_entry_rcu(i, head) \ - for (i = rcu_dereference(head); i != NULL; i = rcu_dereference(i->next)) - -static u32 nft_hash_rnd __read_mostly; -static bool nft_hash_rnd_initted __read_mostly; - -static unsigned int nft_hash_data(const struct nft_data *data, - unsigned int hsize, unsigned int len) -{ - unsigned int h; - - h = jhash(data->data, len, nft_hash_rnd); - return h & (hsize - 1); -} - static bool nft_hash_lookup(const struct nft_set *set, const struct nft_data *key, struct nft_data *data) { - const struct nft_hash *priv = nft_set_priv(set); - const struct nft_hash_table *tbl = rcu_dereference(priv->tbl); + const struct rhashtable *priv = nft_set_priv(set); const struct nft_hash_elem *he; - unsigned int h; - - h = nft_hash_data(key, tbl->size, set->klen); - nft_hash_for_each_entry_rcu(he, tbl->buckets[h]) { - if (nft_data_cmp(&he->key, key, set->klen)) - continue; - if (set->flags & NFT_SET_MAP) - nft_data_copy(data, he->data); - return true; - } - return false; -} - -static void nft_hash_tbl_free(const struct nft_hash_table *tbl) -{ - kvfree(tbl); -} - -static unsigned int nft_hash_tbl_size(unsigned int nelem) -{ - return max(roundup_pow_of_two(nelem * 4 / 3), NFT_HASH_MIN_SIZE); -} - -static struct nft_hash_table *nft_hash_tbl_alloc(unsigned int nbuckets) -{ - struct nft_hash_table *tbl; - size_t size; - - size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); - tbl = kzalloc(size, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN); - if (tbl == NULL) - tbl = vzalloc(size); - if (tbl == NULL) - return NULL; - tbl->size = nbuckets; - - return tbl; -} - -static void nft_hash_chain_unzip(const struct nft_set *set, - const struct nft_hash_table *ntbl, - struct nft_hash_table *tbl, unsigned int n) -{ - struct nft_hash_elem *he, *last, *next; - unsigned int h; - - he = nft_dereference(tbl->buckets[n]); - if (he == NULL) - return; - h = nft_hash_data(&he->key, ntbl->size, set->klen); - - /* Find last element of first chain hashing to bucket h */ - last = he; - nft_hash_for_each_entry(he, he->next) { - if (nft_hash_data(&he->key, ntbl->size, set->klen) != h) - break; - last = he; - } - - /* Unlink first chain from the old table */ - RCU_INIT_POINTER(tbl->buckets[n], last->next); - /* If end of chain reached, done */ - if (he == NULL) - return; + he = rhashtable_lookup(priv, key); + if (he && set->flags & NFT_SET_MAP) + nft_data_copy(data, he->data); - /* Find first element of second chain hashing to bucket h */ - next = NULL; - nft_hash_for_each_entry(he, he->next) { - if (nft_hash_data(&he->key, ntbl->size, set->klen) != h) - continue; - next = he; - break; - } - - /* Link the two chains */ - RCU_INIT_POINTER(last->next, next); -} - -static int nft_hash_tbl_expand(const struct nft_set *set, struct nft_hash *priv) -{ - struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl; - struct nft_hash_elem *he; - unsigned int i, h; - bool complete; - - ntbl = nft_hash_tbl_alloc(tbl->size * 2); - if (ntbl == NULL) - return -ENOMEM; - - /* Link new table's buckets to first element in the old table - * hashing to the new bucket. - */ - for (i = 0; i < ntbl->size; i++) { - h = i < tbl->size ? i : i - tbl->size; - nft_hash_for_each_entry(he, tbl->buckets[h]) { - if (nft_hash_data(&he->key, ntbl->size, set->klen) != i) - continue; - RCU_INIT_POINTER(ntbl->buckets[i], he); - break; - } - } - - /* Publish new table */ - rcu_assign_pointer(priv->tbl, ntbl); - - /* Unzip interleaved hash chains */ - do { - /* Wait for readers to use new table/unzipped chains */ - synchronize_rcu(); - - complete = true; - for (i = 0; i < tbl->size; i++) { - nft_hash_chain_unzip(set, ntbl, tbl, i); - if (tbl->buckets[i] != NULL) - complete = false; - } - } while (!complete); - - nft_hash_tbl_free(tbl); - return 0; -} - -static int nft_hash_tbl_shrink(const struct nft_set *set, struct nft_hash *priv) -{ - struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl; - struct nft_hash_elem __rcu **pprev; - unsigned int i; - - ntbl = nft_hash_tbl_alloc(tbl->size / 2); - if (ntbl == NULL) - return -ENOMEM; - - for (i = 0; i < ntbl->size; i++) { - ntbl->buckets[i] = tbl->buckets[i]; - - for (pprev = &ntbl->buckets[i]; *pprev != NULL; - pprev = &nft_dereference(*pprev)->next) - ; - RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]); - } - - /* Publish new table */ - rcu_assign_pointer(priv->tbl, ntbl); - synchronize_rcu(); - - nft_hash_tbl_free(tbl); - return 0; + return !!he; } static int nft_hash_insert(const struct nft_set *set, const struct nft_set_elem *elem) { - struct nft_hash *priv = nft_set_priv(set); - struct nft_hash_table *tbl = nft_dereference(priv->tbl); + struct rhashtable *priv = nft_set_priv(set); struct nft_hash_elem *he; - unsigned int size, h; + unsigned int size; if (elem->flags != 0) return -EINVAL; @@ -234,13 +65,7 @@ static int nft_hash_insert(const struct nft_set *set, if (set->flags & NFT_SET_MAP) nft_data_copy(he->data, &elem->data); - h = nft_hash_data(&he->key, tbl->size, set->klen); - RCU_INIT_POINTER(he->next, tbl->buckets[h]); - rcu_assign_pointer(tbl->buckets[h], he); - - /* Expand table when exceeding 75% load */ - if (set->nelems + 1 > tbl->size / 4 * 3) - nft_hash_tbl_expand(set, priv); + rhashtable_insert(priv, &he->node, GFP_KERNEL); return 0; } @@ -257,36 +82,31 @@ static void nft_hash_elem_destroy(const struct nft_set *set, static void nft_hash_remove(const struct nft_set *set, const struct nft_set_elem *elem) { - struct nft_hash *priv = nft_set_priv(set); - struct nft_hash_table *tbl = nft_dereference(priv->tbl); - struct nft_hash_elem *he, __rcu **pprev; + struct rhashtable *priv = nft_set_priv(set); + struct rhash_head *he, __rcu **pprev; pprev = elem->cookie; - he = nft_dereference((*pprev)); + he = rht_dereference((*pprev), priv); + + rhashtable_remove_pprev(priv, he, pprev, GFP_KERNEL); - RCU_INIT_POINTER(*pprev, he->next); synchronize_rcu(); kfree(he); - - /* Shrink table beneath 30% load */ - if (set->nelems - 1 < tbl->size * 3 / 10 && - tbl->size > NFT_HASH_MIN_SIZE) - nft_hash_tbl_shrink(set, priv); } static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem) { - const struct nft_hash *priv = nft_set_priv(set); - const struct nft_hash_table *tbl = nft_dereference(priv->tbl); - struct nft_hash_elem __rcu * const *pprev; + 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; - unsigned int h; + u32 h; - h = nft_hash_data(&elem->key, tbl->size, set->klen); + h = rhashtable_hashfn(priv, &elem->key, set->klen); pprev = &tbl->buckets[h]; - nft_hash_for_each_entry(he, 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->next; + pprev = &he->node.next; continue; } @@ -302,14 +122,15 @@ static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem) static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set, struct nft_set_iter *iter) { - const struct nft_hash *priv = nft_set_priv(set); - const struct nft_hash_table *tbl = nft_dereference(priv->tbl); + const struct rhashtable *priv = nft_set_priv(set); + const struct bucket_table *tbl; const struct nft_hash_elem *he; struct nft_set_elem elem; unsigned int i; + tbl = rht_dereference_rcu(priv->tbl, priv); for (i = 0; i < tbl->size; i++) { - nft_hash_for_each_entry(he, tbl->buckets[i]) { + rht_for_each_entry_rcu(he, tbl->buckets[i], node) { if (iter->count < iter->skip) goto cont; @@ -329,48 +150,46 @@ cont: static unsigned int nft_hash_privsize(const struct nlattr * const nla[]) { - return sizeof(struct nft_hash); + return sizeof(struct rhashtable); +} + +static int lockdep_nfnl_lock_is_held(void) +{ + return lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES); } static int nft_hash_init(const struct nft_set *set, const struct nft_set_desc *desc, const struct nlattr * const tb[]) { - struct nft_hash *priv = nft_set_priv(set); - struct nft_hash_table *tbl; - unsigned int size; + struct rhashtable *priv = nft_set_priv(set); + struct rhashtable_params params = { + .nelem_hint = desc->size ? : NFT_HASH_ELEMENT_HINT, + .head_offset = offsetof(struct nft_hash_elem, node), + .key_offset = offsetof(struct nft_hash_elem, key), + .key_len = set->klen, + .hashfn = jhash, + .grow_decision = rht_grow_above_75, + .shrink_decision = rht_shrink_below_30, + .mutex_is_held = lockdep_nfnl_lock_is_held, + }; - if (unlikely(!nft_hash_rnd_initted)) { - get_random_bytes(&nft_hash_rnd, 4); - nft_hash_rnd_initted = true; - } - - size = NFT_HASH_MIN_SIZE; - if (desc->size) - size = nft_hash_tbl_size(desc->size); - - tbl = nft_hash_tbl_alloc(size); - if (tbl == NULL) - return -ENOMEM; - RCU_INIT_POINTER(priv->tbl, tbl); - return 0; + return rhashtable_init(priv, ¶ms); } static void nft_hash_destroy(const struct nft_set *set) { - const struct nft_hash *priv = nft_set_priv(set); - const struct nft_hash_table *tbl = nft_dereference(priv->tbl); + const struct rhashtable *priv = nft_set_priv(set); + const struct bucket_table *tbl; struct nft_hash_elem *he, *next; unsigned int i; - for (i = 0; i < tbl->size; i++) { - for (he = nft_dereference(tbl->buckets[i]); he != NULL; - he = next) { - next = nft_dereference(he->next); + tbl = rht_dereference(priv->tbl, priv); + for (i = 0; i < tbl->size; i++) + rht_for_each_entry_safe(he, next, tbl->buckets[i], priv, node) nft_hash_elem_destroy(set, he); - } - } - kfree(tbl); + + rhashtable_destroy(priv); } static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features, @@ -383,8 +202,8 @@ static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features, esize += FIELD_SIZEOF(struct nft_hash_elem, data[0]); if (desc->size) { - est->size = sizeof(struct nft_hash) + - nft_hash_tbl_size(desc->size) * + est->size = sizeof(struct rhashtable) + + roundup_pow_of_two(desc->size * 4 / 3) * sizeof(struct nft_hash_elem *) + desc->size * esize; } else { -- cgit v1.2.3