Commit fac30731 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

tcp: adopt try_cmpxchg() in tcp_release_cb() 



try_cmpxchg() is slighly more efficient (at least on x86),
and smp_load_acquire(&sk->sk_tsq_flags) could avoid a KCSAN report.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20221110174829.3403442-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 3e35f26d

net/ipv4/tcp_output.c

+3 −3
Original line number Diff line number Diff line
@@ -1077,15 +1077,15 @@ static void tcp_tasklet_func(struct tasklet_struct *t) 
 */

void tcp_release_cb(struct sock *sk)

{

	unsigned long flags, nflags;

	unsigned long flags = smp_load_acquire(&sk->sk_tsq_flags);

	unsigned long nflags;



	/* perform an atomic operation only if at least one flag is set */

	do {

		flags = sk->sk_tsq_flags;

		if (!(flags & TCP_DEFERRED_ALL))

			return;

		nflags = flags & ~TCP_DEFERRED_ALL;

	} while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);

	} while (!try_cmpxchg(&sk->sk_tsq_flags, &flags, nflags));



	if (flags & TCPF_TSQ_DEFERRED) {

		tcp_tsq_write(sk);