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netfilter: CLUSTERIP: RCU conversion
- clusterip_lock becomes a spinlock - lockless lookups - kfree() deferred after RCU grace period - rcu_barrier_bh() inserted in clusterip_tg_exit() v2) - As Patrick pointed out, we use atomic_inc_not_zero() in clusterip_config_find_get(). - list_add_rcu() and list_del_rcu() variants are used. - atomic_dec_and_lock() used in clusterip_config_entry_put() Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net>
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0b041f8d1e
commit
d73f33b168
1 changed files with 29 additions and 19 deletions
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@ -53,12 +53,13 @@ struct clusterip_config {
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#endif
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#endif
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enum clusterip_hashmode hash_mode; /* which hashing mode */
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enum clusterip_hashmode hash_mode; /* which hashing mode */
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u_int32_t hash_initval; /* hash initialization */
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u_int32_t hash_initval; /* hash initialization */
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struct rcu_head rcu;
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};
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};
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static LIST_HEAD(clusterip_configs);
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static LIST_HEAD(clusterip_configs);
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/* clusterip_lock protects the clusterip_configs list */
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/* clusterip_lock protects the clusterip_configs list */
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static DEFINE_RWLOCK(clusterip_lock);
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static DEFINE_SPINLOCK(clusterip_lock);
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#ifdef CONFIG_PROC_FS
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#ifdef CONFIG_PROC_FS
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static const struct file_operations clusterip_proc_fops;
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static const struct file_operations clusterip_proc_fops;
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@ -71,11 +72,17 @@ clusterip_config_get(struct clusterip_config *c)
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atomic_inc(&c->refcount);
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atomic_inc(&c->refcount);
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}
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}
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static void clusterip_config_rcu_free(struct rcu_head *head)
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{
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kfree(container_of(head, struct clusterip_config, rcu));
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}
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static inline void
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static inline void
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clusterip_config_put(struct clusterip_config *c)
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clusterip_config_put(struct clusterip_config *c)
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{
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{
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if (atomic_dec_and_test(&c->refcount))
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if (atomic_dec_and_test(&c->refcount))
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kfree(c);
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call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
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}
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}
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/* decrease the count of entries using/referencing this config. If last
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/* decrease the count of entries using/referencing this config. If last
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@ -84,10 +91,11 @@ clusterip_config_put(struct clusterip_config *c)
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static inline void
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static inline void
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clusterip_config_entry_put(struct clusterip_config *c)
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clusterip_config_entry_put(struct clusterip_config *c)
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{
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{
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write_lock_bh(&clusterip_lock);
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local_bh_disable();
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if (atomic_dec_and_test(&c->entries)) {
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if (atomic_dec_and_lock(&c->entries, &clusterip_lock)) {
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list_del(&c->list);
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list_del_rcu(&c->list);
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write_unlock_bh(&clusterip_lock);
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spin_unlock(&clusterip_lock);
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local_bh_enable();
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dev_mc_del(c->dev, c->clustermac);
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dev_mc_del(c->dev, c->clustermac);
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dev_put(c->dev);
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dev_put(c->dev);
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@ -100,7 +108,7 @@ clusterip_config_entry_put(struct clusterip_config *c)
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#endif
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#endif
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return;
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return;
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}
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}
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write_unlock_bh(&clusterip_lock);
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local_bh_enable();
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}
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}
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static struct clusterip_config *
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static struct clusterip_config *
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@ -108,7 +116,7 @@ __clusterip_config_find(__be32 clusterip)
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{
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{
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struct clusterip_config *c;
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struct clusterip_config *c;
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list_for_each_entry(c, &clusterip_configs, list) {
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list_for_each_entry_rcu(c, &clusterip_configs, list) {
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if (c->clusterip == clusterip)
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if (c->clusterip == clusterip)
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return c;
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return c;
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}
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}
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@ -121,16 +129,15 @@ clusterip_config_find_get(__be32 clusterip, int entry)
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{
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{
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struct clusterip_config *c;
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struct clusterip_config *c;
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read_lock_bh(&clusterip_lock);
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rcu_read_lock_bh();
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c = __clusterip_config_find(clusterip);
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c = __clusterip_config_find(clusterip);
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if (!c) {
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if (c) {
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read_unlock_bh(&clusterip_lock);
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if (unlikely(!atomic_inc_not_zero(&c->refcount)))
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return NULL;
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c = NULL;
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else if (entry)
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atomic_inc(&c->entries);
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}
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}
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atomic_inc(&c->refcount);
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rcu_read_unlock_bh();
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if (entry)
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atomic_inc(&c->entries);
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read_unlock_bh(&clusterip_lock);
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return c;
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return c;
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}
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}
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@ -181,9 +188,9 @@ clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
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}
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}
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#endif
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#endif
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write_lock_bh(&clusterip_lock);
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spin_lock_bh(&clusterip_lock);
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list_add(&c->list, &clusterip_configs);
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list_add_rcu(&c->list, &clusterip_configs);
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write_unlock_bh(&clusterip_lock);
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spin_unlock_bh(&clusterip_lock);
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return c;
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return c;
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}
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}
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@ -733,6 +740,9 @@ static void __exit clusterip_tg_exit(void)
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#endif
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#endif
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nf_unregister_hook(&cip_arp_ops);
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nf_unregister_hook(&cip_arp_ops);
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xt_unregister_target(&clusterip_tg_reg);
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xt_unregister_target(&clusterip_tg_reg);
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/* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
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rcu_barrier_bh();
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}
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}
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module_init(clusterip_tg_init);
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module_init(clusterip_tg_init);
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