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authorEric Dumazet <eric.dumazet@gmail.com>2011-04-04 17:04:03 +0200
committerPatrick McHardy <kaber@trash.net>2011-04-04 17:04:03 +0200
commit7f5c6d4f665bb57a19a34ce1fb16cc708c04f219 (patch)
treee804faa506bbf9edcfd1fdadb2ab3749f58836cd /net/netfilter
parent8f7b01a178b8e6a7b663a1bbaa1710756d67b69b (diff)
netfilter: get rid of atomic ops in fast path
We currently use a percpu spinlock to 'protect' rule bytes/packets counters, after various attempts to use RCU instead. Lately we added a seqlock so that get_counters() can run without blocking BH or 'writers'. But we really only need the seqcount in it. Spinlock itself is only locked by the current/owner cpu, so we can remove it completely. This cleanups api, using correct 'writer' vs 'reader' semantic. At replace time, the get_counters() call makes sure all cpus are done using the old table. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Jan Engelhardt <jengelh@medozas.de> Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net/netfilter')
-rw-r--r--net/netfilter/x_tables.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index a9adf4c6b29..52959efca85 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -762,8 +762,8 @@ void xt_compat_unlock(u_int8_t af)
EXPORT_SYMBOL_GPL(xt_compat_unlock);
#endif
-DEFINE_PER_CPU(struct xt_info_lock, xt_info_locks);
-EXPORT_PER_CPU_SYMBOL_GPL(xt_info_locks);
+DEFINE_PER_CPU(seqcount_t, xt_recseq);
+EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq);
static int xt_jumpstack_alloc(struct xt_table_info *i)
{
@@ -1362,10 +1362,7 @@ static int __init xt_init(void)
int rv;
for_each_possible_cpu(i) {
- struct xt_info_lock *lock = &per_cpu(xt_info_locks, i);
-
- seqlock_init(&lock->lock);
- lock->readers = 0;
+ seqcount_init(&per_cpu(xt_recseq, i));
}
xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL);