xfrm: avoid spinlock in get_acqseq()

Use atomic_inc_return() in get_acqseq() to avoid taking a spinlock

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 5 deletions

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 4744b1f6372..e2aacf0ba01 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3019,12 +3019,11 @@ static int pfkey_send_policy_notify(struct xfrm_policy *xp, int dir, struct km_e
 static u32 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;
 }