This is a note to let you know that I've just added the patch titled net/smc: non blocking recvmsg() return -EAGAIN when no data and signal_pending to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-smc-non-blocking-recvmsg-return-eagain-when-no-d.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 1b845f40723eb84e1c6be8c67b9d455ac718afbe Author: Guangguan Wang <guangguan.wang@xxxxxxxxxxxxxxxxx> Date: Thu May 12 11:08:20 2022 +0800 net/smc: non blocking recvmsg() return -EAGAIN when no data and signal_pending [ Upstream commit f3c46e41b32b6266cf60b0985c61748f53bf1c61 ] Non blocking sendmsg will return -EAGAIN when any signal pending and no send space left, while non blocking recvmsg return -EINTR when signal pending and no data received. This may makes confused. As TCP returns -EAGAIN in the conditions described above. Align the behavior of smc with TCP. Fixes: 846e344eb722 ("net/smc: add receive timeout check") Signed-off-by: Guangguan Wang <guangguan.wang@xxxxxxxxxxxxxxxxx> Reviewed-by: Tony Lu <tonylu@xxxxxxxxxxxxxxxxx> Acked-by: Karsten Graul <kgraul@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220512030820.73848-1-guangguan.wang@xxxxxxxxxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c index 97e8369002d7..9e89bd1f706b 100644 --- a/net/smc/smc_rx.c +++ b/net/smc/smc_rx.c @@ -348,12 +348,12 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, } break; } + if (!timeo) + return -EAGAIN; if (signal_pending(current)) { read_done = sock_intr_errno(timeo); break; } - if (!timeo) - return -EAGAIN; } if (!smc_rx_data_available(conn)) {