提交 e47eb5df 编写于 作者: E Eric Dumazet 提交者: David S. Miller

udp: ipv4: do not use sk_dst_lock from softirq context

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: NFengguang Wu <fengguang.wu@intel.com>
Fixes: 97502231 ("udp: ipv4: must add synchronization in udp_sk_rx_dst_set()")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 50dc875f
......@@ -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;
old = xchg(&sk->sk_rx_dst, dst);
dst_release(old);
}
spin_unlock(&sk->sk_dst_lock);
}
/*
......
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