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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Guangguan Wang <guangguan.wang@linux.alibaba.com>,
        Tony Lu <tonylu@linux.alibaba.com>,
        Karsten Graul <kgraul@linux.ibm.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 12/32] net/smc: non blocking recvmsg() return -EAGAIN when no data and signal_pending
Date:   Mon, 16 May 2022 21:36:26 +0200
Message-Id: <20220516193615.140142528@linuxfoundation.org>
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From: Guangguan Wang <guangguan.wang@linux.alibaba.com>

[ 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@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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/smc/smc_rx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index 36340912df48..a7a4e3ce211a 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -349,12 +349,12 @@ 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)) {
-- 
2.35.1