Patch "dm-raid: add a new helper prepare_suspend() in md_personality" has been added to the 6.7-stable tree

Patch "dm-raid: add a new helper prepare_suspend() in md_personality" has been added to the 6.7-stable tree

[Sasha Levin]

This is a note to let you know that I've just added the patch titled

    dm-raid: add a new helper prepare_suspend() in md_personality

to the 6.7-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     dm-raid-add-a-new-helper-prepare_suspend-in-md_perso.patch
and it can be found in the queue-6.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.



commit 2eea0920d6a4eec9ef6bf65a03cc3a32bb1fb44e
Author: Yu Kuai <yukuai3@huawei.com>
Date:   Tue Mar 5 15:23:04 2024 +0800

    dm-raid: add a new helper prepare_suspend() in md_personality
    
    [ Upstream commit 5625ff8b72b0e5c13b0fc1fc1f198155af45f729 ]
    
    There are no functional changes for now, prepare to fix a deadlock for
    dm-raid456.
    
    Cc: stable@vger.kernel.org # v6.7+
    Signed-off-by: Yu Kuai <yukuai3@huawei.com>
    Signed-off-by: Xiao Ni <xni@redhat.com>
    Acked-by: Mike Snitzer <snitzer@kernel.org>
    Signed-off-by: Song Liu <song@kernel.org>
    Link: https://lore.kernel.org/r/20240305072306.2562024-8-yukuai1@huaweicloud.com
    Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 8d38cdb221453..b8f5304ca00d1 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3803,6 +3803,23 @@ static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
 	blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));
 }
 
+static void raid_presuspend(struct dm_target *ti)
+{
+	struct raid_set *rs = ti->private;
+	struct mddev *mddev = &rs->md;
+
+	if (!reshape_interrupted(mddev))
+		return;
+
+	/*
+	 * For raid456, if reshape is interrupted, IO across reshape position
+	 * will never make progress, while caller will wait for IO to be done.
+	 * Inform raid456 to handle those IO to prevent deadlock.
+	 */
+	if (mddev->pers && mddev->pers->prepare_suspend)
+		mddev->pers->prepare_suspend(mddev);
+}
+
 static void raid_postsuspend(struct dm_target *ti)
 {
 	struct raid_set *rs = ti->private;
@@ -4087,6 +4104,7 @@ static struct target_type raid_target = {
 	.message = raid_message,
 	.iterate_devices = raid_iterate_devices,
 	.io_hints = raid_io_hints,
+	.presuspend = raid_presuspend,
 	.postsuspend = raid_postsuspend,
 	.preresume = raid_preresume,
 	.resume = raid_resume,
diff --git a/drivers/md/md.h b/drivers/md/md.h
index ea0fd76c17e75..24261f9b676d5 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -649,6 +649,7 @@ struct md_personality
 	int (*start_reshape) (struct mddev *mddev);
 	void (*finish_reshape) (struct mddev *mddev);
 	void (*update_reshape_pos) (struct mddev *mddev);
+	void (*prepare_suspend) (struct mddev *mddev);
 	/* quiesce suspends or resumes internal processing.
 	 * 1 - stop new actions and wait for action io to complete
 	 * 0 - return to normal behaviour