[PATCH 3.13.y-ckt 091/156] dm: hold suspend_lock while suspending device during device deletion

From: Kamal Mostafa
Date: Tue Apr 07 2015 - 19:15:43 EST

3.13.11-ckt19 -stable review patch. If anyone has any objections, please let me know.


From: Mikulas Patocka <mpatocka@xxxxxxxxxx>

commit ab7c7bb6f4ab95dbca96fcfc4463cd69843e3e24 upstream.

__dm_destroy() must take the suspend_lock so that its presuspend and
postsuspend calls do not race with an internal suspend.

Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
drivers/md/dm.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index b8570e9..5489410 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2485,10 +2485,16 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
set_bit(DMF_FREEING, &md->flags);

+ /*
+ * Take suspend_lock so that presuspend and postsuspend methods
+ * do not race with internal suspend.
+ */
+ mutex_lock(&md->suspend_lock);
if (!dm_suspended_md(md)) {
+ mutex_unlock(&md->suspend_lock);

/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
dm_put_live_table(md, srcu_idx);

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