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From: Yu Kuai <yukuai1@huaweicloud.com>
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Subject: [PATCH v5 14/14] dm-raid: remove mddev_suspend/resume()
Date: Thu,  1 Feb 2024 17:25:59 +0800
Message-Id: <20240201092559.910982-15-yukuai1@huaweicloud.com>
In-Reply-To: <20240201092559.910982-1-yukuai1@huaweicloud.com>
References: <20240201092559.910982-1-yukuai1@huaweicloud.com>
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From: Yu Kuai <yukuai3@huawei.com>

dm layer will make sure that no new IO can be issued and will wait for
all dispatched IO to be done during suspend or before removing the
device. Hence there is no need to call mddev_suspend/resume() again.

BTW, mddev_suspend/resume() can't gurantee that there are no sync IO,
and previous patch make sure that presuspend will stop sync thread.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 drivers/md/dm-raid.c |  8 +++-----
 drivers/md/md.c      | 11 +++++++++++
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 5f78cc19d6f3..ed8c28952b14 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3241,7 +3241,7 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	rs->md.in_sync = 1;
 
 	/* Has to be held on running the array */
-	mddev_suspend_and_lock_nointr(&rs->md);
+	mddev_lock_nointr(&rs->md);
 
 	/* Keep array frozen until resume. */
 	md_frozen_sync_thread(&rs->md);
@@ -3829,11 +3829,9 @@ static void raid_postsuspend(struct dm_target *ti)
 {
 	struct raid_set *rs = ti->private;
 
-	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
+	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
 		/* Writes have to be stopped before suspending to avoid deadlocks. */
 		md_stop_writes(&rs->md);
-		mddev_suspend(&rs->md, false);
-	}
 }
 
 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
@@ -4091,7 +4089,7 @@ static void raid_resume(struct dm_target *ti)
 		mddev->ro = 0;
 		mddev->in_sync = 0;
 		md_unfrozen_sync_thread(mddev);
-		mddev_unlock_and_resume(mddev);
+		mddev_unlock(mddev);
 	}
 }
 
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2c245341148a..a8db84c200fe 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -437,6 +437,10 @@ int mddev_suspend(struct mddev *mddev, bool interruptible)
 {
 	int err = 0;
 
+	/* Array is supended from dm_suspend() for dm-raid. */
+	if (!mddev->gendisk)
+		return 0;
+
 	/*
 	 * hold reconfig_mutex to wait for normal io will deadlock, because
 	 * other context can't update super_block, and normal io can rely on
@@ -488,6 +492,13 @@ EXPORT_SYMBOL_GPL(mddev_suspend);
 
 static void __mddev_resume(struct mddev *mddev, bool recovery_needed)
 {
+	/*
+	 * Array is supended from dm_suspend() and resumed from dm_resume() for
+	 * dm-raid.
+	 */
+	if (!mddev->gendisk)
+		return;
+
 	lockdep_assert_not_held(&mddev->reconfig_mutex);
 
 	mutex_lock(&mddev->suspend_mutex);
-- 
2.39.2