From: Christoph Hellwig <hch@lst.de>
Date: Fri, 27 Nov 2020 15:21:42 +0000 (+0100)
Subject: dm: remove the block_device reference in struct mapped_device
X-Git-Tag: accepted/tizen/unified/20230118.172025~8262^2~64
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b0519b542303bc167d22bf11dadd3f18d37dbfe2;p=platform%2Fkernel%2Flinux-rpi.git

dm: remove the block_device reference in struct mapped_device

Get rid of the long-lasting struct block_device reference in
struct mapped_device.  The only remaining user is the freeze code,
where we can trivially look up the block device at freeze time
and release the reference at thaw time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index aace147..086d293 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -102,8 +102,6 @@ struct mapped_device {
 	/* kobject and completion */
 	struct dm_kobject_holder kobj_holder;
 
-	struct block_device *bdev;
-
 	struct dm_stats stats;
 
 	/* for blk-mq request-based DM support */
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ab0a833..48051db 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1744,11 +1744,6 @@ static void cleanup_mapped_device(struct mapped_device *md)
 
 	cleanup_srcu_struct(&md->io_barrier);
 
-	if (md->bdev) {
-		bdput(md->bdev);
-		md->bdev = NULL;
-	}
-
 	mutex_destroy(&md->suspend_lock);
 	mutex_destroy(&md->type_lock);
 	mutex_destroy(&md->table_devices_lock);
@@ -1840,10 +1835,6 @@ static struct mapped_device *alloc_dev(int minor)
 	if (!md->wq)
 		goto bad;
 
-	md->bdev = bdget_disk(md->disk, 0);
-	if (!md->bdev)
-		goto bad;
-
 	dm_stats_init(&md->stats);
 
 	/* Populate the mapping, nobody knows we exist yet */
@@ -2384,11 +2375,16 @@ out:
  */
 static int lock_fs(struct mapped_device *md)
 {
+	struct block_device *bdev;
 	int r;
 
 	WARN_ON(test_bit(DMF_FROZEN, &md->flags));
 
-	r = freeze_bdev(md->bdev);
+	bdev = bdget_disk(md->disk, 0);
+	if (!bdev)
+		return -ENOMEM;
+	r = freeze_bdev(bdev);
+	bdput(bdev);
 	if (!r)
 		set_bit(DMF_FROZEN, &md->flags);
 	return r;
@@ -2396,9 +2392,16 @@ static int lock_fs(struct mapped_device *md)
 
 static void unlock_fs(struct mapped_device *md)
 {
+	struct block_device *bdev;
+
 	if (!test_bit(DMF_FROZEN, &md->flags))
 		return;
-	thaw_bdev(md->bdev);
+
+	bdev = bdget_disk(md->disk, 0);
+	if (!bdev)
+		return;
+	thaw_bdev(bdev);
+	bdput(bdev);
 	clear_bit(DMF_FROZEN, &md->flags);
 }