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 <tgraf@suug.ch> Acked-by: Patrick McHardy <kaber@trash.net> Reviewed-by: Nikolay Aleksandrov <nikolay@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Thomas Graf
David S. Miller
parent
e341694e3e
commit
cfe4a9dda0
1 changed files with 55 additions and 236 deletions
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@ -15,209 +15,40 @@
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#include <linux/log2.h>
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#include <linux/jhash.h>
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#include <linux/netlink.h>
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#include <linux/vmalloc.h>
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#include <linux/rhashtable.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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#define NFT_HASH_MIN_SIZE 4UL
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struct nft_hash {
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struct nft_hash_table __rcu *tbl;
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};
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struct nft_hash_table {
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unsigned int size;
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struct nft_hash_elem __rcu *buckets[];
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};
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/* We target a hash table size of 4, element hint is 75% of final size */
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#define NFT_HASH_ELEMENT_HINT 3
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struct nft_hash_elem {
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struct nft_hash_elem __rcu *next;
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struct rhash_head node;
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struct nft_data key;
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struct nft_data data[];
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};
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#define nft_hash_for_each_entry(i, head) \
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for (i = nft_dereference(head); i != NULL; i = nft_dereference(i->next))
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#define nft_hash_for_each_entry_rcu(i, head) \
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for (i = rcu_dereference(head); i != NULL; i = rcu_dereference(i->next))
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static u32 nft_hash_rnd __read_mostly;
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static bool nft_hash_rnd_initted __read_mostly;
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static unsigned int nft_hash_data(const struct nft_data *data,
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unsigned int hsize, unsigned int len)
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{
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unsigned int h;
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h = jhash(data->data, len, nft_hash_rnd);
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return h & (hsize - 1);
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}
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static bool nft_hash_lookup(const struct nft_set *set,
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const struct nft_data *key,
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struct nft_data *data)
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{
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const struct nft_hash *priv = nft_set_priv(set);
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const struct nft_hash_table *tbl = rcu_dereference(priv->tbl);
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const struct rhashtable *priv = nft_set_priv(set);
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const struct nft_hash_elem *he;
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unsigned int h;
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h = nft_hash_data(key, tbl->size, set->klen);
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nft_hash_for_each_entry_rcu(he, tbl->buckets[h]) {
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if (nft_data_cmp(&he->key, key, set->klen))
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continue;
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(data, he->data);
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return true;
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}
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return false;
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}
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he = rhashtable_lookup(priv, key);
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if (he && set->flags & NFT_SET_MAP)
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nft_data_copy(data, he->data);
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static void nft_hash_tbl_free(const struct nft_hash_table *tbl)
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{
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kvfree(tbl);
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}
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static unsigned int nft_hash_tbl_size(unsigned int nelem)
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{
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return max(roundup_pow_of_two(nelem * 4 / 3), NFT_HASH_MIN_SIZE);
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}
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static struct nft_hash_table *nft_hash_tbl_alloc(unsigned int nbuckets)
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{
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struct nft_hash_table *tbl;
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size_t size;
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size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
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tbl = kzalloc(size, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN);
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if (tbl == NULL)
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tbl = vzalloc(size);
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if (tbl == NULL)
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return NULL;
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tbl->size = nbuckets;
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return tbl;
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}
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static void nft_hash_chain_unzip(const struct nft_set *set,
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const struct nft_hash_table *ntbl,
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struct nft_hash_table *tbl, unsigned int n)
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{
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struct nft_hash_elem *he, *last, *next;
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unsigned int h;
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he = nft_dereference(tbl->buckets[n]);
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if (he == NULL)
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return;
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h = nft_hash_data(&he->key, ntbl->size, set->klen);
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/* Find last element of first chain hashing to bucket h */
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last = he;
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nft_hash_for_each_entry(he, he->next) {
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if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
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break;
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last = he;
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}
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/* Unlink first chain from the old table */
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RCU_INIT_POINTER(tbl->buckets[n], last->next);
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/* If end of chain reached, done */
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if (he == NULL)
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return;
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/* Find first element of second chain hashing to bucket h */
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next = NULL;
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nft_hash_for_each_entry(he, he->next) {
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if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
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continue;
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next = he;
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break;
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}
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/* Link the two chains */
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RCU_INIT_POINTER(last->next, next);
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}
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static int nft_hash_tbl_expand(const struct nft_set *set, struct nft_hash *priv)
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{
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struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
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struct nft_hash_elem *he;
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unsigned int i, h;
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bool complete;
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ntbl = nft_hash_tbl_alloc(tbl->size * 2);
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if (ntbl == NULL)
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return -ENOMEM;
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/* Link new table's buckets to first element in the old table
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* hashing to the new bucket.
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*/
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for (i = 0; i < ntbl->size; i++) {
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h = i < tbl->size ? i : i - tbl->size;
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nft_hash_for_each_entry(he, tbl->buckets[h]) {
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if (nft_hash_data(&he->key, ntbl->size, set->klen) != i)
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continue;
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RCU_INIT_POINTER(ntbl->buckets[i], he);
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break;
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}
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}
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/* Publish new table */
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rcu_assign_pointer(priv->tbl, ntbl);
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/* Unzip interleaved hash chains */
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do {
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/* Wait for readers to use new table/unzipped chains */
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synchronize_rcu();
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complete = true;
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for (i = 0; i < tbl->size; i++) {
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nft_hash_chain_unzip(set, ntbl, tbl, i);
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if (tbl->buckets[i] != NULL)
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complete = false;
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}
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} while (!complete);
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nft_hash_tbl_free(tbl);
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return 0;
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}
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static int nft_hash_tbl_shrink(const struct nft_set *set, struct nft_hash *priv)
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{
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struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
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struct nft_hash_elem __rcu **pprev;
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unsigned int i;
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ntbl = nft_hash_tbl_alloc(tbl->size / 2);
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if (ntbl == NULL)
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return -ENOMEM;
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for (i = 0; i < ntbl->size; i++) {
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ntbl->buckets[i] = tbl->buckets[i];
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for (pprev = &ntbl->buckets[i]; *pprev != NULL;
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pprev = &nft_dereference(*pprev)->next)
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;
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RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
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}
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/* Publish new table */
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rcu_assign_pointer(priv->tbl, ntbl);
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synchronize_rcu();
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nft_hash_tbl_free(tbl);
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return 0;
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return !!he;
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}
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static int nft_hash_insert(const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_hash *priv = nft_set_priv(set);
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struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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struct rhashtable *priv = nft_set_priv(set);
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struct nft_hash_elem *he;
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unsigned int size, h;
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unsigned int size;
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if (elem->flags != 0)
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return -EINVAL;
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@ -234,13 +65,7 @@ static int nft_hash_insert(const struct nft_set *set,
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(he->data, &elem->data);
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h = nft_hash_data(&he->key, tbl->size, set->klen);
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RCU_INIT_POINTER(he->next, tbl->buckets[h]);
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rcu_assign_pointer(tbl->buckets[h], he);
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/* Expand table when exceeding 75% load */
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if (set->nelems + 1 > tbl->size / 4 * 3)
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nft_hash_tbl_expand(set, priv);
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rhashtable_insert(priv, &he->node, GFP_KERNEL);
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return 0;
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}
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@ -257,36 +82,31 @@ static void nft_hash_elem_destroy(const struct nft_set *set,
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static void nft_hash_remove(const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_hash *priv = nft_set_priv(set);
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struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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struct nft_hash_elem *he, __rcu **pprev;
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struct rhashtable *priv = nft_set_priv(set);
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struct rhash_head *he, __rcu **pprev;
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pprev = elem->cookie;
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he = nft_dereference((*pprev));
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he = rht_dereference((*pprev), priv);
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rhashtable_remove_pprev(priv, he, pprev, GFP_KERNEL);
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RCU_INIT_POINTER(*pprev, he->next);
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synchronize_rcu();
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kfree(he);
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/* Shrink table beneath 30% load */
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if (set->nelems - 1 < tbl->size * 3 / 10 &&
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tbl->size > NFT_HASH_MIN_SIZE)
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nft_hash_tbl_shrink(set, priv);
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}
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static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem)
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{
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const struct nft_hash *priv = nft_set_priv(set);
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const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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struct nft_hash_elem __rcu * const *pprev;
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const struct rhashtable *priv = nft_set_priv(set);
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const struct bucket_table *tbl = rht_dereference_rcu(priv->tbl, priv);
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struct rhash_head __rcu * const *pprev;
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struct nft_hash_elem *he;
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unsigned int h;
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u32 h;
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h = nft_hash_data(&elem->key, tbl->size, set->klen);
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h = rhashtable_hashfn(priv, &elem->key, set->klen);
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pprev = &tbl->buckets[h];
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nft_hash_for_each_entry(he, tbl->buckets[h]) {
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rht_for_each_entry_rcu(he, tbl->buckets[h], node) {
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if (nft_data_cmp(&he->key, &elem->key, set->klen)) {
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pprev = &he->next;
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pprev = &he->node.next;
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continue;
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}
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@ -302,14 +122,15 @@ static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem)
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static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
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struct nft_set_iter *iter)
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{
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const struct nft_hash *priv = nft_set_priv(set);
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const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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const struct rhashtable *priv = nft_set_priv(set);
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const struct bucket_table *tbl;
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const struct nft_hash_elem *he;
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struct nft_set_elem elem;
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unsigned int i;
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tbl = rht_dereference_rcu(priv->tbl, priv);
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for (i = 0; i < tbl->size; i++) {
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nft_hash_for_each_entry(he, tbl->buckets[i]) {
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rht_for_each_entry_rcu(he, tbl->buckets[i], node) {
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if (iter->count < iter->skip)
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goto cont;
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@ -329,48 +150,46 @@ static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
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static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
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{
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return sizeof(struct nft_hash);
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return sizeof(struct rhashtable);
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}
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static int lockdep_nfnl_lock_is_held(void)
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{
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return lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES);
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}
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static int nft_hash_init(const struct nft_set *set,
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const struct nft_set_desc *desc,
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const struct nlattr * const tb[])
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{
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struct nft_hash *priv = nft_set_priv(set);
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struct nft_hash_table *tbl;
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unsigned int size;
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struct rhashtable *priv = nft_set_priv(set);
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struct rhashtable_params params = {
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.nelem_hint = desc->size ? : NFT_HASH_ELEMENT_HINT,
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.head_offset = offsetof(struct nft_hash_elem, node),
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.key_offset = offsetof(struct nft_hash_elem, key),
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.key_len = set->klen,
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.hashfn = jhash,
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.grow_decision = rht_grow_above_75,
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.shrink_decision = rht_shrink_below_30,
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.mutex_is_held = lockdep_nfnl_lock_is_held,
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};
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if (unlikely(!nft_hash_rnd_initted)) {
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get_random_bytes(&nft_hash_rnd, 4);
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nft_hash_rnd_initted = true;
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}
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size = NFT_HASH_MIN_SIZE;
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if (desc->size)
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size = nft_hash_tbl_size(desc->size);
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tbl = nft_hash_tbl_alloc(size);
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if (tbl == NULL)
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return -ENOMEM;
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RCU_INIT_POINTER(priv->tbl, tbl);
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return 0;
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return rhashtable_init(priv, ¶ms);
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}
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static void nft_hash_destroy(const struct nft_set *set)
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{
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const struct nft_hash *priv = nft_set_priv(set);
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const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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const struct rhashtable *priv = nft_set_priv(set);
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const struct bucket_table *tbl;
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struct nft_hash_elem *he, *next;
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unsigned int i;
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for (i = 0; i < tbl->size; i++) {
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for (he = nft_dereference(tbl->buckets[i]); he != NULL;
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he = next) {
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next = nft_dereference(he->next);
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tbl = rht_dereference(priv->tbl, priv);
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for (i = 0; i < tbl->size; i++)
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rht_for_each_entry_safe(he, next, tbl->buckets[i], priv, node)
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nft_hash_elem_destroy(set, he);
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}
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}
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kfree(tbl);
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rhashtable_destroy(priv);
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}
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static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
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@ -383,8 +202,8 @@ static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
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esize += FIELD_SIZEOF(struct nft_hash_elem, data[0]);
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if (desc->size) {
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est->size = sizeof(struct nft_hash) +
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nft_hash_tbl_size(desc->size) *
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est->size = sizeof(struct rhashtable) +
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roundup_pow_of_two(desc->size * 4 / 3) *
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sizeof(struct nft_hash_elem *) +
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desc->size * esize;
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} else {
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