diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-06-01 12:00:41 +0200 |
|---|---|---|
| committer | Patrick McHardy <kaber@trash.net> | 2010-06-01 12:00:41 +0200 |
| commit | fabf3a85ab88063c10f367cccba7b3a1e59df996 (patch) | |
| tree | 7c1ea5590906e50359dd10c590a778f84abe3ca1 /net/netfilter | |
| parent | a8b563894d6fee9b90b7d6ed76f8ec28ad45bcbe (diff) | |
| download | linux-fabf3a85ab88063c10f367cccba7b3a1e59df996.tar.bz2 | |
netfilter: xt_statistic: remove nth_lock spinlock
Use atomic_cmpxchg() to avoid dirtying a shared location.
xt_statistic_priv smp aligned to avoid sharing same cache line with
other stuff.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/xt_statistic.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/net/netfilter/xt_statistic.c b/net/netfilter/xt_statistic.c index 96e62b8fd6b1..42ecb71d445f 100644 --- a/net/netfilter/xt_statistic.c +++ b/net/netfilter/xt_statistic.c @@ -18,8 +18,8 @@ #include <linux/netfilter/x_tables.h> struct xt_statistic_priv { - uint32_t count; -}; + atomic_t count; +} ____cacheline_aligned_in_smp; MODULE_LICENSE("GPL"); MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); @@ -27,13 +27,12 @@ MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)"); MODULE_ALIAS("ipt_statistic"); MODULE_ALIAS("ip6t_statistic"); -static DEFINE_SPINLOCK(nth_lock); - static bool statistic_mt(const struct sk_buff *skb, struct xt_action_param *par) { const struct xt_statistic_info *info = par->matchinfo; bool ret = info->flags & XT_STATISTIC_INVERT; + int nval, oval; switch (info->mode) { case XT_STATISTIC_MODE_RANDOM: @@ -41,12 +40,12 @@ statistic_mt(const struct sk_buff *skb, struct xt_action_param *par) ret = !ret; break; case XT_STATISTIC_MODE_NTH: - spin_lock_bh(&nth_lock); - if (info->master->count++ == info->u.nth.every) { - info->master->count = 0; + do { + oval = atomic_read(&info->master->count); + nval = (oval == info->u.nth.every) ? 0 : oval + 1; + } while (atomic_cmpxchg(&info->master->count, oval, nval) != oval); + if (nval == 0) ret = !ret; - } - spin_unlock_bh(&nth_lock); break; } @@ -64,7 +63,7 @@ static int statistic_mt_check(const struct xt_mtchk_param *par) info->master = kzalloc(sizeof(*info->master), GFP_KERNEL); if (info->master == NULL) return -ENOMEM; - info->master->count = info->u.nth.count; + atomic_set(&info->master->count, info->u.nth.count); return 0; } |