[ 144/171] libceph: protect ceph_con_open() with mutex

[Greg Kroah-Hartman]

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

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

From: Sage Weil <sage@xxxxxxxxxxx>

(cherry picked from commit 5469155f2bc83bb2c88b0a0370c3d54d87eed06e)

Take the con mutex while we are initiating a ceph open.  This is necessary
because the may have previously been in use and then closed, which could
result in a racing workqueue running con_work().

Signed-off-by: Sage Weil <sage@xxxxxxxxxxx>
Reviewed-by: Yehuda Sadeh <yehuda@xxxxxxxxxxx>
Reviewed-by: Alex Elder <elder@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ceph/messenger.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -537,6 +537,7 @@ void ceph_con_open(struct ceph_connectio
 		   __u8 entity_type, __u64 entity_num,
 		   struct ceph_entity_addr *addr)
 {
+	mutex_lock(&con->mutex);
 	dout("con_open %p %s\n", con, ceph_pr_addr(&addr->in_addr));
 	set_bit(OPENING, &con->state);
 	WARN_ON(!test_and_clear_bit(CLOSED, &con->state));
@@ -546,6 +547,7 @@ void ceph_con_open(struct ceph_connectio
 
 	memcpy(&con->peer_addr, addr, sizeof(*addr));
 	con->delay = 0;      /* reset backoff memory */
+	mutex_unlock(&con->mutex);
 	queue_con(con);
 }
 EXPORT_SYMBOL(ceph_con_open);


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