netdev - [PATCH net 2/2] net/smc: Don't call clcsock shutdown twice when smc shutdown

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Date:   Thu, 25 Nov 2021 14:19:35 +0800
From:   Tony Lu <tonylu@...ux.alibaba.com>
To:     kgraul@...ux.ibm.com
Cc:     kuba@...nel.org, davem@...emloft.net, netdev@...r.kernel.org,
        linux-s390@...r.kernel.org, linux-rdma@...r.kernel.org
Subject: [PATCH net 2/2] net/smc: Don't call clcsock shutdown twice when smc shutdown

When applications call shutdown() with SHUT_RDWR in userspace,
smc_close_active() calls kernel_sock_shutdown(), and it is called
twice in smc_shutdown().

This fixes this by checking sk_state before do clcsock shutdown, and
avoids missing the application's call of smc_shutdown().

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")
Signed-off-by: Tony Lu <tonylu@...ux.alibaba.com>
Reviewed-by: Wen Gu <guwen@...ux.alibaba.com>
---
 net/smc/af_smc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 4b62c925a13e..7b04cb4d15f4 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2373,6 +2373,7 @@ static int smc_shutdown(struct socket *sock, int how)
 	struct smc_sock *smc;
 	int rc = -EINVAL;
 	int rc1 = 0;
+	int old_state;
 
 	smc = smc_sk(sk);
 
@@ -2398,7 +2399,12 @@ static int smc_shutdown(struct socket *sock, int how)
 	}
 	switch (how) {
 	case SHUT_RDWR:		/* shutdown in both directions */
+		old_state = sk->sk_state;
 		rc = smc_close_active(smc);
+		if (old_state == SMC_ACTIVE &&
+		    sk->sk_state == SMC_PEERCLOSEWAIT1)
+			goto out_no_shutdown;
+
 		break;
 	case SHUT_WR:
 		rc = smc_close_shutdown_write(smc);
@@ -2410,6 +2416,8 @@ static int smc_shutdown(struct socket *sock, int how)
 	}
 	if (smc->clcsock)
 		rc1 = kernel_sock_shutdown(smc->clcsock, how);
+
+out_no_shutdown:
 	/* map sock_shutdown_cmd constants to sk_shutdown value range */
 	sk->sk_shutdown |= how + 1;
 
-- 
2.32.0.3.g01195cf9f