[PATCH 4.19 78/88] net/smc: postpone release of clcsock

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ursula Braun <ubraun@linux.ibm.com>

[ Upstream commit b03faa1fafc8018295401dc558bdc76362d860a4 ]

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>
Stable-dep-of: 5211c9729484 ("net/smc: fix dangling sock under state SMC_APPFINCLOSEWAIT")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 dcd00b514c3f9..6f342f6cc4876 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -143,32 +143,33 @@ 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 092696d738c00..3e7858793d485 100644
--- a/net/smc/smc_close.c
+++ b/net/smc/smc_close.c
@@ -415,8 +415,13 @@ 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 */
-- 
2.42.0