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>

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 4744b1f..e2aacf0 100644 (file)
--- 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;
 }