From 6836b9bdd98e3b500cd49512484df68f46e14659 Mon Sep 17 00:00:00 2001 From: jamal Date: Tue, 16 Feb 2010 02:01:22 +0000 Subject: [PATCH] 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 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 Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/xfrm/xfrm_state.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index f50ee9badf47..96f2088e7448 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -1462,12 +1462,12 @@ EXPORT_SYMBOL(xfrm_find_acq_byseq); u32 xfrm_get_acqseq(void) { u32 res; - static u32 acqseq; - static DEFINE_SPINLOCK(acqseq_lock); + static atomic_t acqseq; + + do { + res = atomic_inc_return(&acqseq); + } while (!res); - spin_lock_bh(&acqseq_lock); - res = (++acqseq ? : ++acqseq); - spin_unlock_bh(&acqseq_lock); return res; } EXPORT_SYMBOL(xfrm_get_acqseq); -- 2.20.1