[PATCH 3.19 59/75] dm: hold suspend_lock while suspending device during device deletion

From: Greg Kroah-Hartman
Date: Fri Apr 10 2015 - 09:33:50 EST

3.19-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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/md/dm.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2526,10 +2526,16 @@ static void __dm_destroy(struct mapped_d
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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