xfrm: avoid spinlock in get_acqseq() used by xfrm user
Eric's version fixed it for pfkey. This one is for xfrm user.
I thought about amortizing those two get_acqseq()s but it seems
reasonable to have two of these sequence spaces for the two different
interfaces.
cheers,
jamal
commit d5168d5addbc999c94aacda8f28a4a173756a72b
Author: Jamal Hadi Salim <hadi@cyberus.ca>
Date: Tue Feb 16 06:51:22 2010 -0500
xfrm: avoid spinlock in get_acqseq() used by xfrm user
This is in the same spirit as commit 28aecb9d7728dc26bf03ce7925fe622023a83a2a
by Eric Dumazet.
Use atomic_inc_return() in get_acqseq() to avoid taking a spinlock
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index f50ee9b..96f2088 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1462,12 +1462,12 @@
u32 xfrm_get_acqseq(void)
{
u32 res;
- static u32 acqseq;
- static DEFINE_SPINLOCK(acqseq_lock);
+ static atomic_t acqseq;
- spin_lock_bh(&acqseq_lock);
- res = (++acqseq ? : ++acqseq);
- spin_unlock_bh(&acqseq_lock);
+ do {
+ res = atomic_inc_return(&acqseq);
+ } while (!res);
+
return res;
}
EXPORT_SYMBOL(xfrm_get_acqseq);
