libceph: move ceph_con_send() closed check under the con mutex

(cherry picked from commit a59b55a602b6c741052d79c1e3643f8440cddd27)

Take the con mutex before checking whether the connection is closed to
avoid racing with someone else closing it.

Signed-off-by: Sage Weil <sage@inktank.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 9 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 14d24b778ca9..cb871fc7286f 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2453,22 +2453,20 @@ static void clear_standby(struct ceph_connection *con)
  */
 void ceph_con_send(struct ceph_connection *con, struct ceph_msg *msg)
 {
-	if (test_bit(CLOSED, &con->state)) {
-		dout("con_send %p closed, dropping %p\n", con, msg);
-		ceph_msg_put(msg);
-		return;
-	}
-
 	/* set src+dst */
 	msg->hdr.src = con->msgr->inst.name;
-
 	BUG_ON(msg->front.iov_len != le32_to_cpu(msg->hdr.front_len));
-
 	msg->needs_out_seq = true;
 
-	/* queue */
 	mutex_lock(&con->mutex);
 
+	if (test_bit(CLOSED, &con->state)) {
+		dout("con_send %p closed, dropping %p\n", con, msg);
+		ceph_msg_put(msg);
+		mutex_unlock(&con->mutex);
+		return;
+	}
+
 	BUG_ON(msg->con != NULL);
 	msg->con = con->ops->get(con);
 	BUG_ON(msg->con == NULL);