net/smc: non blocking recvmsg() return -EAGAIN when no data and signal_pending

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@linux.alibaba.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Link: https://lore.kernel.org/r/20220512030820.73848-1-guangguan.wang@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index 51e8eb2..338b9ef 100644 (file)
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -355,12 +355,12 @@ 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)) {