[PATCH RESEND net] net/smc: Keep smc_close_final rc during active close

When smc_close_final() returns error, the return code overwrites by
kernel_sock_shutdown() in smc_close_active(). The return code of
smc_close_final() is more important than kernel_sock_shutdown(), and it
will pass to userspace directly.

Fix it by keeping both return codes, if smc_close_final() raises an
error, return it or kernel_sock_shutdown()'s.

Link: https://lore.kernel.org/linux-s390/1f67548e-cbf6-0dce-82b5-10288a4583bd@linux.ibm.com/
Fixes: 606a63c9783a ("net/smc: Ensure the active closing peer first closes clcsock")
Suggested-by: Karsten Graul <redacted>
Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Acked-by: Karsten Graul <redacted>
---
 net/smc/smc_close.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c
index 3715d2f5ad55..292e4d904ab6 100644
--- a/net/smc/smc_close.c
+++ b/net/smc/smc_close.c

@@ -195,6 +195,7 @@ int smc_close_active(struct smc_sock *smc)
 	int old_state;
 	long timeout;
 	int rc = 0;
+	int rc1 = 0;
 
 	timeout = current->flags & PF_EXITING ?
 		  0 : sock_flag(sk, SOCK_LINGER) ?

@@ -232,8 +233,11 @@ int smc_close_active(struct smc_sock *smc)
 			/* actively shutdown clcsock before peer close it,
 			 * prevent peer from entering TIME_WAIT state.
 			 */
-			if (smc->clcsock && smc->clcsock->sk)
-				rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
+			if (smc->clcsock && smc->clcsock->sk) {
+				rc1 = kernel_sock_shutdown(smc->clcsock,
+							   SHUT_RDWR);
+				rc = rc ? rc : rc1;
+			}
 		} else {
 			/* peer event has changed the state */
 			goto again;

-- 
2.32.0.3.g01195cf9f

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller [off-list ref]:

On Wed,  1 Dec 2021 14:42:16 +0800 you wrote:

When smc_close_final() returns error, the return code overwrites by
kernel_sock_shutdown() in smc_close_active(). The return code of
smc_close_final() is more important than kernel_sock_shutdown(), and it
will pass to userspace directly.

Fix it by keeping both return codes, if smc_close_final() raises an
error, return it or kernel_sock_shutdown()'s.

[...]

Here is the summary with links:
  - [RESEND,net] net/smc: Keep smc_close_final rc during active close
    https://git.kernel.org/netdev/net/c/00e158fb91df

You are awesome, thank you!
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