dm: fix handling of multiple internal suspends (96b26c8c) · Commits · 戴 / test

Commit ("dm: enhance internal suspend and resume interface") attempted to handle multiple internal suspends on the same device, but it did that incorrectly. When these functions are called in this order on the same device the device is no longer suspended, but it should be: dm_internal_suspend_noflush dm_internal_suspend_noflush dm_internal_resume Fix this bug by maintaining an 'internal_suspend_count' and resuming the device when this count drops to zero. Signed-off-by:

Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:

Mike Snitzer <snitzer@redhat.com>

drivers/md/dm.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -206,6 +206,9 @@ struct mapped_device {
		/* zero-length flush that will be cloned and submitted to targets */
		struct bio flush_bio;

		/* the number of internal suspends */
		unsigned internal_suspend_count;

		struct dm_stats stats;
		};

		@@ -2928,7 +2931,7 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla
		{
		struct dm_table *map = NULL;

		if (dm_suspended_internally_md(md))
		if (md->internal_suspend_count++)
		return; /* nested internal suspend */

		if (dm_suspended_md(md)) {
		@@ -2953,7 +2956,9 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla

		static void __dm_internal_resume(struct mapped_device *md)
		{
		if (!dm_suspended_internally_md(md))
		BUG_ON(!md->internal_suspend_count);

		if (--md->internal_suspend_count)
		return; /* resume from nested internal suspend */

		if (dm_suspended_md(md))

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