From 7f5c6d4f665bb57a19a34ce1fb16cc708c04f219 Mon Sep 17 00:00:00 2001 From: Eric Dumazet <eric.dumazet@gmail.com> Date: Mon, 4 Apr 2011 17:04:03 +0200 Subject: 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> --- net/netfilter/x_tables.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'net/netfilter') 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); -- cgit v1.2.3-18-g5258