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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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6eba82248e
Reallocation is only required for shrinking and expanding and both rely on a mutex for synchronization and callers of rhashtable_init() are in non atomic context. Therefore, no reason to continue passing allocation hints through the API. Instead, use GFP_KERNEL and add __GFP_NOWARN | __GFP_NORETRY to allow for silent fall back to vzalloc() without the OOM killer jumping in as pointed out by Eric Dumazet and Eric W. Biederman. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
258 lines
6.4 KiB
C
258 lines
6.4 KiB
C
/*
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* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/list.h>
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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/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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/* 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 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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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 rhashtable *priv = nft_set_priv(set);
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const struct nft_hash_elem *he;
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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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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 rhashtable *priv = nft_set_priv(set);
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struct nft_hash_elem *he;
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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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size = sizeof(*he);
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if (set->flags & NFT_SET_MAP)
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size += sizeof(he->data[0]);
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he = kzalloc(size, GFP_KERNEL);
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if (he == NULL)
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return -ENOMEM;
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nft_data_copy(&he->key, &elem->key);
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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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rhashtable_insert(priv, &he->node);
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return 0;
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}
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static void nft_hash_elem_destroy(const struct nft_set *set,
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struct nft_hash_elem *he)
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{
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nft_data_uninit(&he->key, NFT_DATA_VALUE);
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if (set->flags & NFT_SET_MAP)
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nft_data_uninit(he->data, set->dtype);
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kfree(he);
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}
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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 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 = rht_dereference((*pprev), priv);
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rhashtable_remove_pprev(priv, he, pprev);
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synchronize_rcu();
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kfree(he);
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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 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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u32 h;
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h = rhashtable_hashfn(priv, &elem->key, set->klen);
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pprev = &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->node.next;
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continue;
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}
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elem->cookie = (void *)pprev;
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elem->flags = 0;
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(&elem->data, he->data);
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return 0;
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}
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return -ENOENT;
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}
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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 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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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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memcpy(&elem.key, &he->key, sizeof(elem.key));
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if (set->flags & NFT_SET_MAP)
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memcpy(&elem.data, he->data, sizeof(elem.data));
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elem.flags = 0;
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iter->err = iter->fn(ctx, set, iter, &elem);
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if (iter->err < 0)
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return;
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cont:
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iter->count++;
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}
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}
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}
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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 rhashtable);
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}
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#ifdef CONFIG_PROVE_LOCKING
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static int lockdep_nfnl_lock_is_held(void *parent)
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{
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return lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES);
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}
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#endif
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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 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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#ifdef CONFIG_PROVE_LOCKING
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.mutex_is_held = lockdep_nfnl_lock_is_held,
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#endif
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};
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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 rhashtable *priv = nft_set_priv(set);
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const struct bucket_table *tbl = priv->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 = rht_entry(tbl->buckets[i], struct nft_hash_elem, node);
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he != NULL; he = next) {
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next = rht_entry(he->node.next, struct nft_hash_elem, node);
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nft_hash_elem_destroy(set, he);
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}
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}
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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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struct nft_set_estimate *est)
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{
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unsigned int esize;
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esize = sizeof(struct nft_hash_elem);
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if (features & NFT_SET_MAP)
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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 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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/* Resizing happens when the load drops below 30% or goes
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* above 75%. The average of 52.5% load (approximated by 50%)
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* is used for the size estimation of the hash buckets,
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* meaning we calculate two buckets per element.
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*/
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est->size = esize + 2 * sizeof(struct nft_hash_elem *);
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}
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est->class = NFT_SET_CLASS_O_1;
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return true;
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}
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static struct nft_set_ops nft_hash_ops __read_mostly = {
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.privsize = nft_hash_privsize,
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.estimate = nft_hash_estimate,
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.init = nft_hash_init,
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.destroy = nft_hash_destroy,
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.get = nft_hash_get,
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.insert = nft_hash_insert,
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.remove = nft_hash_remove,
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.lookup = nft_hash_lookup,
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.walk = nft_hash_walk,
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.features = NFT_SET_MAP,
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.owner = THIS_MODULE,
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};
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static int __init nft_hash_module_init(void)
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{
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return nft_register_set(&nft_hash_ops);
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}
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static void __exit nft_hash_module_exit(void)
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{
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nft_unregister_set(&nft_hash_ops);
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}
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module_init(nft_hash_module_init);
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module_exit(nft_hash_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_ALIAS_NFT_SET();
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