Message ID | 1387133626.19078.216.camel@edumazet-glaptop2.roam.corp.google.com |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Sun, 15 Dec 2013 10:53:46 -0800 > From: Eric Dumazet <edumazet@google.com> > > Using sk_dst_lock from softirq context is not supported right now. > > Instead of adding BH protection everywhere, > udp_sk_rx_dst_set() can instead use xchg(), as suggested > by David. > > Reported-by: Fengguang Wu <fengguang.wu@intel.com> > Fixes: 975022310233 ("udp: ipv4: must add synchronization in udp_sk_rx_dst_set()") > Signed-off-by: Eric Dumazet <edumazet@google.com> Applied, thanks Eric. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 62c19fdd102d..f140048334ce 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1600,20 +1600,15 @@ static void flush_stack(struct sock **stack, unsigned int count, } /* For TCP sockets, sk_rx_dst is protected by socket lock - * For UDP, we use sk_dst_lock to guard against concurrent changes. + * For UDP, we use xchg() to guard against concurrent changes. */ static void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst) { struct dst_entry *old; - spin_lock(&sk->sk_dst_lock); - old = sk->sk_rx_dst; - if (likely(old != dst)) { - dst_hold(dst); - sk->sk_rx_dst = dst; - dst_release(old); - } - spin_unlock(&sk->sk_dst_lock); + dst_hold(dst); + old = xchg(&sk->sk_rx_dst, dst); + dst_release(old); } /*