Commit a562c0a2 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

sctp: fix busy polling 



Busy polling while holding the socket lock makes litle sense,
because incoming packets wont reach our receive queue.

Fixes: 8465a5fc ("sctp: add support for busy polling to sctp protocol")
Reported-by: default avatarJacob Moroni <jmoroni@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: Xin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b15a4cfe

net/sctp/socket.c

+4 −6
Original line number Diff line number Diff line
@@ -2102,6 +2102,10 @@ static int sctp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 
	if (unlikely(flags & MSG_ERRQUEUE))

		return inet_recv_error(sk, msg, len, addr_len);



	if (sk_can_busy_loop(sk) &&

	    skb_queue_empty_lockless(&sk->sk_receive_queue))

		sk_busy_loop(sk, flags & MSG_DONTWAIT);



	lock_sock(sk);



	if (sctp_style(sk, TCP) && !sctp_sstate(sk, ESTABLISHED) &&
@@ -9046,12 +9050,6 @@ struct sk_buff *sctp_skb_recv_datagram(struct sock *sk, int flags, int *err) 
		if (sk->sk_shutdown & RCV_SHUTDOWN)

			break;



		if (sk_can_busy_loop(sk)) {

			sk_busy_loop(sk, flags & MSG_DONTWAIT);



			if (!skb_queue_empty_lockless(&sk->sk_receive_queue))

				continue;

		}



		/* User doesn't want to wait.  */

		error = -EAGAIN;