From: Ursula Braun <ubraun@linux.ibm.com>
Date: Thu, 7 Feb 2019 15:56:15 +0100
Subject: net/smc: postpone release of clcsock
Git-commit: b03faa1fafc8018295401dc558bdc76362d860a4
Patch-mainline: v5.1-rc1
References: bsc#1129857 bsc#1129861 LTC#176247 LTC#176250

According to RFC7609 (http://www.rfc-editor.org/info/rfc7609)
first the SMC-R connection is shut down and then the normal TCP
connection FIN processing drives cleanup of the internal TCP connection.
The unconditional release of the clcsock during active socket closing
has to be postponed if the peer has not yet signalled socket closing.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 net/smc/af_smc.c    | 33 +++++++++++++++++----------------
 net/smc/smc_close.c |  7 ++++++-
 2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 369870b0ef79..60ccc8f50368 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -145,32 +145,33 @@ static int smc_release(struct socket *sock)
 		rc = smc_close_active(smc);
 		sock_set_flag(sk, SOCK_DEAD);
 		sk->sk_shutdown |= SHUTDOWN_MASK;
-	}
-
-	sk->sk_prot->unhash(sk);
-
-	if (smc->clcsock) {
-		if (smc->use_fallback && sk->sk_state == SMC_LISTEN) {
+	} else {
+		if (sk->sk_state != SMC_LISTEN && sk->sk_state != SMC_INIT)
+			sock_put(sk); /* passive closing */
+		if (sk->sk_state == SMC_LISTEN) {
 			/* wake up clcsock accept */
 			rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
 		}
-		mutex_lock(&smc->clcsock_release_lock);
-		sock_release(smc->clcsock);
-		smc->clcsock = NULL;
-		mutex_unlock(&smc->clcsock_release_lock);
-	}
-	if (smc->use_fallback) {
-		if (sk->sk_state != SMC_LISTEN && sk->sk_state != SMC_INIT)
-			sock_put(sk); /* passive closing */
 		sk->sk_state = SMC_CLOSED;
 		sk->sk_state_change(sk);
 	}
 
+	sk->sk_prot->unhash(sk);
+
+	if (sk->sk_state == SMC_CLOSED) {
+		if (smc->clcsock) {
+			mutex_lock(&smc->clcsock_release_lock);
+			sock_release(smc->clcsock);
+			smc->clcsock = NULL;
+			mutex_unlock(&smc->clcsock_release_lock);
+		}
+		if (!smc->use_fallback)
+			smc_conn_free(&smc->conn);
+	}
+
 	/* detach socket */
 	sock_orphan(sk);
 	sock->sk = NULL;
-	if (!smc->use_fallback && sk->sk_state == SMC_CLOSED)
-		smc_conn_free(&smc->conn);
 	release_sock(sk);
 
 	sock_put(sk); /* final sock_put */
diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c
index ea2b87f29469..0e60dd741698 100644
--- a/net/smc/smc_close.c
+++ b/net/smc/smc_close.c
@@ -405,8 +405,13 @@ static void smc_close_passive_work(struct work_struct *work)
 	if (old_state != sk->sk_state) {
 		sk->sk_state_change(sk);
 		if ((sk->sk_state == SMC_CLOSED) &&
-		    (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket))
+		    (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket)) {
 			smc_conn_free(conn);
+			if (smc->clcsock) {
+				sock_release(smc->clcsock);
+				smc->clcsock = NULL;
+			}
+		}
 	}
 	release_sock(sk);
 	sock_put(sk); /* sock_hold done by schedulers of close_work */