* [PATCH nf-next-2.6] netfilter: CLUSTERIP: RCU conversion
@ 2010-06-09 16:11 Eric Dumazet
2010-06-09 16:30 ` Patrick McHardy
0 siblings, 1 reply; 6+ messages in thread
From: Eric Dumazet @ 2010-06-09 16:11 UTC (permalink / raw)
To: Patrick McHardy; +Cc: Netfilter Development Mailinglist
- clusterip_lock becomes a spinlock
- lockless lookups
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
net/ipv4/netfilter/ipt_CLUSTERIP.c | 40 ++++++++++++++++-----------
1 file changed, 24 insertions(+), 16 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index f91c94b..d83ad7f 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -53,12 +53,13 @@ struct clusterip_config {
#endif
enum clusterip_hashmode hash_mode; /* which hashing mode */
u_int32_t hash_initval; /* hash initialization */
+ struct rcu_head rcu;
};
static LIST_HEAD(clusterip_configs);
/* clusterip_lock protects the clusterip_configs list */
-static DEFINE_RWLOCK(clusterip_lock);
+static DEFINE_SPINLOCK(clusterip_lock);
#ifdef CONFIG_PROC_FS
static const struct file_operations clusterip_proc_fops;
@@ -71,11 +72,17 @@ clusterip_config_get(struct clusterip_config *c)
atomic_inc(&c->refcount);
}
+
+static void clusterip_config_rcu_free(struct rcu_head *head)
+{
+ kfree(container_of(head, struct clusterip_config, rcu));
+}
+
static inline void
clusterip_config_put(struct clusterip_config *c)
{
if (atomic_dec_and_test(&c->refcount))
- kfree(c);
+ call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
}
/* decrease the count of entries using/referencing this config. If last
@@ -84,10 +91,10 @@ clusterip_config_put(struct clusterip_config *c)
static inline void
clusterip_config_entry_put(struct clusterip_config *c)
{
- write_lock_bh(&clusterip_lock);
+ spin_lock_bh(&clusterip_lock);
if (atomic_dec_and_test(&c->entries)) {
list_del(&c->list);
- write_unlock_bh(&clusterip_lock);
+ spin_unlock_bh(&clusterip_lock);
dev_mc_del(c->dev, c->clustermac);
dev_put(c->dev);
@@ -100,7 +107,7 @@ clusterip_config_entry_put(struct clusterip_config *c)
#endif
return;
}
- write_unlock_bh(&clusterip_lock);
+ spin_unlock_bh(&clusterip_lock);
}
static struct clusterip_config *
@@ -108,7 +115,7 @@ __clusterip_config_find(__be32 clusterip)
{
struct clusterip_config *c;
- list_for_each_entry(c, &clusterip_configs, list) {
+ list_for_each_entry_rcu(c, &clusterip_configs, list) {
if (c->clusterip == clusterip)
return c;
}
@@ -121,16 +128,14 @@ clusterip_config_find_get(__be32 clusterip, int entry)
{
struct clusterip_config *c;
- read_lock_bh(&clusterip_lock);
+ rcu_read_lock_bh();
c = __clusterip_config_find(clusterip);
- if (!c) {
- read_unlock_bh(&clusterip_lock);
- return NULL;
+ if (c) {
+ atomic_inc(&c->refcount);
+ if (entry)
+ atomic_inc(&c->entries);
}
- atomic_inc(&c->refcount);
- if (entry)
- atomic_inc(&c->entries);
- read_unlock_bh(&clusterip_lock);
+ rcu_read_unlock_bh();
return c;
}
@@ -181,9 +186,9 @@ clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
}
#endif
- write_lock_bh(&clusterip_lock);
+ spin_lock_bh(&clusterip_lock);
list_add(&c->list, &clusterip_configs);
- write_unlock_bh(&clusterip_lock);
+ spin_unlock_bh(&clusterip_lock);
return c;
}
@@ -733,6 +738,9 @@ static void __exit clusterip_tg_exit(void)
#endif
nf_unregister_hook(&cip_arp_ops);
xt_unregister_target(&clusterip_tg_reg);
+
+ /* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
+ rcu_barrier_bh();
}
module_init(clusterip_tg_init);
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH nf-next-2.6] netfilter: CLUSTERIP: RCU conversion
2010-06-09 16:11 [PATCH nf-next-2.6] netfilter: CLUSTERIP: RCU conversion Eric Dumazet
@ 2010-06-09 16:30 ` Patrick McHardy
2010-06-09 17:11 ` Eric Dumazet
0 siblings, 1 reply; 6+ messages in thread
From: Patrick McHardy @ 2010-06-09 16:30 UTC (permalink / raw)
To: Eric Dumazet; +Cc: Netfilter Development Mailinglist
Eric Dumazet wrote:
> @@ -121,16 +128,14 @@ clusterip_config_find_get(__be32 clusterip, int entry)
> {
> struct clusterip_config *c;
>
> - read_lock_bh(&clusterip_lock);
> + rcu_read_lock_bh();
> c = __clusterip_config_find(clusterip);
> - if (!c) {
> - read_unlock_bh(&clusterip_lock);
> - return NULL;
> + if (c) {
> + atomic_inc(&c->refcount);
> + if (entry)
> + atomic_inc(&c->entries);
>
Shouldn't this be using atomic_inc_not_zero() to avoid races with
clusterip_config_entry_put()?
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH nf-next-2.6] netfilter: CLUSTERIP: RCU conversion
2010-06-09 16:30 ` Patrick McHardy
@ 2010-06-09 17:11 ` Eric Dumazet
2010-06-14 16:29 ` Patrick McHardy
0 siblings, 1 reply; 6+ messages in thread
From: Eric Dumazet @ 2010-06-09 17:11 UTC (permalink / raw)
To: Patrick McHardy; +Cc: Netfilter Development Mailinglist
Le mercredi 09 juin 2010 à 18:30 +0200, Patrick McHardy a écrit :
> Eric Dumazet wrote:
> > @@ -121,16 +128,14 @@ clusterip_config_find_get(__be32 clusterip, int entry)
> > {
> > struct clusterip_config *c;
> >
> > - read_lock_bh(&clusterip_lock);
> > + rcu_read_lock_bh();
> > c = __clusterip_config_find(clusterip);
> > - if (!c) {
> > - read_unlock_bh(&clusterip_lock);
> > - return NULL;
> > + if (c) {
> > + atomic_inc(&c->refcount);
> > + if (entry)
> > + atomic_inc(&c->entries);
> >
>
> Shouldn't this be using atomic_inc_not_zero() to avoid races with
> clusterip_config_entry_put()?
>
Ah yes, I should stop doing patches today !
Hmm, I am not sure current code is correct ?
clusterip_config_find_get() can return a struct clusterip_config pointer
to an entry just that was given to clusterip_config_entry_put()
(c->entries == 0)
Then we access c->dev, while clusterip_config_entry_put() did a
dev_put(c->dev) on it ?
So following 'standard rcu lookup' works, but race is still there ?
static inline struct clusterip_config *
clusterip_config_find_get(__be32 clusterip, int entry)
{
struct clusterip_config *c;
rcu_read_lock_bh();
c = __clusterip_config_find(clusterip);
if (c) {
if (unlikely(!atomic_inc_not_zero(&c->refcount)))
c = NULL;
else if (entry)
atomic_inc(&c->entries);
}
rcu_read_unlock_bh();
return c;
}
updated patch for reference :
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index f91c94b..ecd77b1 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -53,12 +53,13 @@ struct clusterip_config {
#endif
enum clusterip_hashmode hash_mode; /* which hashing mode */
u_int32_t hash_initval; /* hash initialization */
+ struct rcu_head rcu;
};
static LIST_HEAD(clusterip_configs);
/* clusterip_lock protects the clusterip_configs list */
-static DEFINE_RWLOCK(clusterip_lock);
+static DEFINE_SPINLOCK(clusterip_lock);
#ifdef CONFIG_PROC_FS
static const struct file_operations clusterip_proc_fops;
@@ -71,11 +72,17 @@ clusterip_config_get(struct clusterip_config *c)
atomic_inc(&c->refcount);
}
+
+static void clusterip_config_rcu_free(struct rcu_head *head)
+{
+ kfree(container_of(head, struct clusterip_config, rcu));
+}
+
static inline void
clusterip_config_put(struct clusterip_config *c)
{
if (atomic_dec_and_test(&c->refcount))
- kfree(c);
+ call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
}
/* decrease the count of entries using/referencing this config. If last
@@ -84,10 +91,10 @@ clusterip_config_put(struct clusterip_config *c)
static inline void
clusterip_config_entry_put(struct clusterip_config *c)
{
- write_lock_bh(&clusterip_lock);
+ spin_lock_bh(&clusterip_lock);
if (atomic_dec_and_test(&c->entries)) {
list_del(&c->list);
- write_unlock_bh(&clusterip_lock);
+ spin_unlock_bh(&clusterip_lock);
dev_mc_del(c->dev, c->clustermac);
dev_put(c->dev);
@@ -100,7 +107,7 @@ clusterip_config_entry_put(struct clusterip_config *c)
#endif
return;
}
- write_unlock_bh(&clusterip_lock);
+ spin_unlock_bh(&clusterip_lock);
}
static struct clusterip_config *
@@ -108,7 +115,7 @@ __clusterip_config_find(__be32 clusterip)
{
struct clusterip_config *c;
- list_for_each_entry(c, &clusterip_configs, list) {
+ list_for_each_entry_rcu(c, &clusterip_configs, list) {
if (c->clusterip == clusterip)
return c;
}
@@ -121,16 +128,15 @@ clusterip_config_find_get(__be32 clusterip, int entry)
{
struct clusterip_config *c;
- read_lock_bh(&clusterip_lock);
+ rcu_read_lock_bh();
c = __clusterip_config_find(clusterip);
- if (!c) {
- read_unlock_bh(&clusterip_lock);
- return NULL;
+ if (c) {
+ if (unlikely(!atomic_inc_not_zero(&c->refcount)))
+ c = NULL;
+ else if (entry)
+ atomic_inc(&c->entries);
}
- atomic_inc(&c->refcount);
- if (entry)
- atomic_inc(&c->entries);
- read_unlock_bh(&clusterip_lock);
+ rcu_read_unlock_bh();
return c;
}
@@ -181,9 +187,9 @@ clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
}
#endif
- write_lock_bh(&clusterip_lock);
+ spin_lock_bh(&clusterip_lock);
list_add(&c->list, &clusterip_configs);
- write_unlock_bh(&clusterip_lock);
+ spin_unlock_bh(&clusterip_lock);
return c;
}
@@ -733,6 +739,9 @@ static void __exit clusterip_tg_exit(void)
#endif
nf_unregister_hook(&cip_arp_ops);
xt_unregister_target(&clusterip_tg_reg);
+
+ /* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
+ rcu_barrier_bh();
}
module_init(clusterip_tg_init);
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH nf-next-2.6] netfilter: CLUSTERIP: RCU conversion
2010-06-09 17:11 ` Eric Dumazet
@ 2010-06-14 16:29 ` Patrick McHardy
2010-06-14 19:59 ` Eric Dumazet
0 siblings, 1 reply; 6+ messages in thread
From: Patrick McHardy @ 2010-06-14 16:29 UTC (permalink / raw)
To: Eric Dumazet; +Cc: Netfilter Development Mailinglist
Eric Dumazet wrote:
> Le mercredi 09 juin 2010 à 18:30 +0200, Patrick McHardy a écrit :
>
>> Eric Dumazet wrote:
>>
>>> @@ -121,16 +128,14 @@ clusterip_config_find_get(__be32 clusterip, int entry)
>>> {
>>> struct clusterip_config *c;
>>>
>>> - read_lock_bh(&clusterip_lock);
>>> + rcu_read_lock_bh();
>>> c = __clusterip_config_find(clusterip);
>>> - if (!c) {
>>> - read_unlock_bh(&clusterip_lock);
>>> - return NULL;
>>> + if (c) {
>>> + atomic_inc(&c->refcount);
>>> + if (entry)
>>> + atomic_inc(&c->entries);
>>>
>>>
>> Shouldn't this be using atomic_inc_not_zero() to avoid races with
>> clusterip_config_entry_put()?
>>
>>
>
> Ah yes, I should stop doing patches today !
>
> Hmm, I am not sure current code is correct ?
>
> clusterip_config_find_get() can return a struct clusterip_config pointer
> to an entry just that was given to clusterip_config_entry_put()
> (c->entries == 0)
>
> Then we access c->dev, while clusterip_config_entry_put() did a
> dev_put(c->dev) on it ?
>
In the clusterip_tg_check() case we hold a "entries" reference, so
this can't happen. In arp_mangle() the device pointer is only used
for comparison (except for the pr_debug statement), so at least it
won't crash.
I wonder why this isn't simply using the refcount for both rule
entries and other references.
> So following 'standard rcu lookup' works, but race is still there ?
>
> static inline struct clusterip_config *
> clusterip_config_find_get(__be32 clusterip, int entry)
> {
> struct clusterip_config *c;
>
> rcu_read_lock_bh();
> c = __clusterip_config_find(clusterip);
> if (c) {
> if (unlikely(!atomic_inc_not_zero(&c->refcount)))
> c = NULL;
> else if (entry)
> atomic_inc(&c->entries);
> }
> rcu_read_unlock_bh();
>
> return c;
> }
>
>
> updated patch for reference :
>
> diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
> index f91c94b..ecd77b1 100644
> --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
> +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
> @@ -53,12 +53,13 @@ struct clusterip_config {
> #endif
> enum clusterip_hashmode hash_mode; /* which hashing mode */
> u_int32_t hash_initval; /* hash initialization */
> + struct rcu_head rcu;
> };
>
> static LIST_HEAD(clusterip_configs);
>
> /* clusterip_lock protects the clusterip_configs list */
> -static DEFINE_RWLOCK(clusterip_lock);
> +static DEFINE_SPINLOCK(clusterip_lock);
>
> #ifdef CONFIG_PROC_FS
> static const struct file_operations clusterip_proc_fops;
> @@ -71,11 +72,17 @@ clusterip_config_get(struct clusterip_config *c)
> atomic_inc(&c->refcount);
> }
>
> +
> +static void clusterip_config_rcu_free(struct rcu_head *head)
> +{
> + kfree(container_of(head, struct clusterip_config, rcu));
> +}
> +
> static inline void
> clusterip_config_put(struct clusterip_config *c)
> {
> if (atomic_dec_and_test(&c->refcount))
> - kfree(c);
> + call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
> }
>
> /* decrease the count of entries using/referencing this config. If last
> @@ -84,10 +91,10 @@ clusterip_config_put(struct clusterip_config *c)
> static inline void
> clusterip_config_entry_put(struct clusterip_config *c)
> {
> - write_lock_bh(&clusterip_lock);
> + spin_lock_bh(&clusterip_lock);
> if (atomic_dec_and_test(&c->entries)) {
> list_del(&c->list);
> - write_unlock_bh(&clusterip_lock);
> + spin_unlock_bh(&clusterip_lock);
>
> dev_mc_del(c->dev, c->clustermac);
> dev_put(c->dev);
> @@ -100,7 +107,7 @@ clusterip_config_entry_put(struct clusterip_config *c)
> #endif
> return;
> }
> - write_unlock_bh(&clusterip_lock);
> + spin_unlock_bh(&clusterip_lock);
> }
>
> static struct clusterip_config *
> @@ -108,7 +115,7 @@ __clusterip_config_find(__be32 clusterip)
> {
> struct clusterip_config *c;
>
> - list_for_each_entry(c, &clusterip_configs, list) {
> + list_for_each_entry_rcu(c, &clusterip_configs, list) {
> if (c->clusterip == clusterip)
> return c;
> }
> @@ -121,16 +128,15 @@ clusterip_config_find_get(__be32 clusterip, int entry)
> {
> struct clusterip_config *c;
>
> - read_lock_bh(&clusterip_lock);
> + rcu_read_lock_bh();
> c = __clusterip_config_find(clusterip);
> - if (!c) {
> - read_unlock_bh(&clusterip_lock);
> - return NULL;
> + if (c) {
> + if (unlikely(!atomic_inc_not_zero(&c->refcount)))
> + c = NULL;
> + else if (entry)
> + atomic_inc(&c->entries);
> }
> - atomic_inc(&c->refcount);
> - if (entry)
> - atomic_inc(&c->entries);
> - read_unlock_bh(&clusterip_lock);
> + rcu_read_unlock_bh();
>
> return c;
> }
> @@ -181,9 +187,9 @@ clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
> }
> #endif
>
> - write_lock_bh(&clusterip_lock);
> + spin_lock_bh(&clusterip_lock);
> list_add(&c->list, &clusterip_configs);
> - write_unlock_bh(&clusterip_lock);
> + spin_unlock_bh(&clusterip_lock);
>
> return c;
> }
> @@ -733,6 +739,9 @@ static void __exit clusterip_tg_exit(void)
> #endif
> nf_unregister_hook(&cip_arp_ops);
> xt_unregister_target(&clusterip_tg_reg);
> +
> + /* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
> + rcu_barrier_bh();
> }
>
> module_init(clusterip_tg_init);
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
>
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH nf-next-2.6] netfilter: CLUSTERIP: RCU conversion
2010-06-14 16:29 ` Patrick McHardy
@ 2010-06-14 19:59 ` Eric Dumazet
2010-06-15 11:10 ` Patrick McHardy
0 siblings, 1 reply; 6+ messages in thread
From: Eric Dumazet @ 2010-06-14 19:59 UTC (permalink / raw)
To: Patrick McHardy; +Cc: Netfilter Development Mailinglist
Le lundi 14 juin 2010 à 18:29 +0200, Patrick McHardy a écrit :
> In the clusterip_tg_check() case we hold a "entries" reference, so
> this can't happen. In arp_mangle() the device pointer is only used
> for comparison (except for the pr_debug statement), so at least it
> won't crash.
>
> I wonder why this isn't simply using the refcount for both rule
> entries and other references.
>
So there is no race. Since arp_mangle() runs in a non preempt section,
rcu grace period of device dismantle protects us.
Thanks !
[PATCH nf-next-2.6 v2] 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>
---
net/ipv4/netfilter/ipt_CLUSTERIP.c | 48 ++++++++++++++++-----------
1 file changed, 29 insertions(+), 19 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index f91c94b..64d0875 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -53,12 +53,13 @@ struct clusterip_config {
#endif
enum clusterip_hashmode hash_mode; /* which hashing mode */
u_int32_t hash_initval; /* hash initialization */
+ struct rcu_head rcu;
};
static LIST_HEAD(clusterip_configs);
/* clusterip_lock protects the clusterip_configs list */
-static DEFINE_RWLOCK(clusterip_lock);
+static DEFINE_SPINLOCK(clusterip_lock);
#ifdef CONFIG_PROC_FS
static const struct file_operations clusterip_proc_fops;
@@ -71,11 +72,17 @@ clusterip_config_get(struct clusterip_config *c)
atomic_inc(&c->refcount);
}
+
+static void clusterip_config_rcu_free(struct rcu_head *head)
+{
+ kfree(container_of(head, struct clusterip_config, rcu));
+}
+
static inline void
clusterip_config_put(struct clusterip_config *c)
{
if (atomic_dec_and_test(&c->refcount))
- kfree(c);
+ call_rcu_bh(&c->rcu, clusterip_config_rcu_free);
}
/* decrease the count of entries using/referencing this config. If last
@@ -84,10 +91,11 @@ clusterip_config_put(struct clusterip_config *c)
static inline void
clusterip_config_entry_put(struct clusterip_config *c)
{
- write_lock_bh(&clusterip_lock);
- if (atomic_dec_and_test(&c->entries)) {
- list_del(&c->list);
- write_unlock_bh(&clusterip_lock);
+ local_bh_disable();
+ if (atomic_dec_and_lock(&c->entries, &clusterip_lock)) {
+ list_del_rcu(&c->list);
+ spin_unlock(&clusterip_lock);
+ local_bh_enable();
dev_mc_del(c->dev, c->clustermac);
dev_put(c->dev);
@@ -100,7 +108,7 @@ clusterip_config_entry_put(struct clusterip_config *c)
#endif
return;
}
- write_unlock_bh(&clusterip_lock);
+ local_bh_enable();
}
static struct clusterip_config *
@@ -108,7 +116,7 @@ __clusterip_config_find(__be32 clusterip)
{
struct clusterip_config *c;
- list_for_each_entry(c, &clusterip_configs, list) {
+ list_for_each_entry_rcu(c, &clusterip_configs, list) {
if (c->clusterip == clusterip)
return c;
}
@@ -121,16 +129,15 @@ clusterip_config_find_get(__be32 clusterip, int entry)
{
struct clusterip_config *c;
- read_lock_bh(&clusterip_lock);
+ rcu_read_lock_bh();
c = __clusterip_config_find(clusterip);
- if (!c) {
- read_unlock_bh(&clusterip_lock);
- return NULL;
+ if (c) {
+ if (unlikely(!atomic_inc_not_zero(&c->refcount)))
+ c = NULL;
+ else if (entry)
+ atomic_inc(&c->entries);
}
- atomic_inc(&c->refcount);
- if (entry)
- atomic_inc(&c->entries);
- read_unlock_bh(&clusterip_lock);
+ rcu_read_unlock_bh();
return c;
}
@@ -181,9 +188,9 @@ clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
}
#endif
- write_lock_bh(&clusterip_lock);
- list_add(&c->list, &clusterip_configs);
- write_unlock_bh(&clusterip_lock);
+ spin_lock_bh(&clusterip_lock);
+ list_add_rcu(&c->list, &clusterip_configs);
+ spin_unlock_bh(&clusterip_lock);
return c;
}
@@ -733,6 +740,9 @@ static void __exit clusterip_tg_exit(void)
#endif
nf_unregister_hook(&cip_arp_ops);
xt_unregister_target(&clusterip_tg_reg);
+
+ /* Wait for completion of call_rcu_bh()'s (clusterip_config_rcu_free) */
+ rcu_barrier_bh();
}
module_init(clusterip_tg_init);
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH nf-next-2.6] netfilter: CLUSTERIP: RCU conversion
2010-06-14 19:59 ` Eric Dumazet
@ 2010-06-15 11:10 ` Patrick McHardy
0 siblings, 0 replies; 6+ messages in thread
From: Patrick McHardy @ 2010-06-15 11:10 UTC (permalink / raw)
To: Eric Dumazet; +Cc: Netfilter Development Mailinglist
Eric Dumazet wrote:
> [PATCH nf-next-2.6 v2] 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()
>
Applied, thanks Eric.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-06-15 11:10 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-06-09 16:11 [PATCH nf-next-2.6] netfilter: CLUSTERIP: RCU conversion Eric Dumazet
2010-06-09 16:30 ` Patrick McHardy
2010-06-09 17:11 ` Eric Dumazet
2010-06-14 16:29 ` Patrick McHardy
2010-06-14 19:59 ` Eric Dumazet
2010-06-15 11:10 ` Patrick McHardy
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.