6.1-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit a562c0a2d651e040681b0bfce9b4d229ac3b0b8c ]
Busy polling while holding the socket lock makes litle sense, because incoming packets wont reach our receive queue.
Fixes: 8465a5fcd1ce ("sctp: add support for busy polling to sctp protocol") Reported-by: Jacob Moroni jmoroni@google.com Signed-off-by: Eric Dumazet edumazet@google.com Cc: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Cc: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/sctp/socket.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index da56832179f0..237a6b04adf6 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -2101,6 +2101,10 @@ 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) && @@ -9041,12 +9045,6 @@ 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;