block: don't grab a reference to the whole device in blkdev_get_part

blkdev_get_no_open already acquires a reference to the disk, which has
the same effect as the disk keeps a reference on the whole device bdev.

Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 24a6970f3623aa6f9647881b5c568e09065850ab..7de519dcfdff3777f3d53f7daf27c7f2372481c7 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1282,16 +1282,14 @@ static void blkdev_put_whole(struct block_device *bdev, fmode_t mode)
 static int blkdev_get_part(struct block_device *part, fmode_t mode)
 {
        struct gendisk *disk = part->bd_disk;
-       struct block_device *whole;
        int ret;
 
        if (part->bd_openers)
                goto done;
 
-       whole = bdgrab(disk->part0);
-       ret = blkdev_get_whole(whole, mode);
+       ret = blkdev_get_whole(bdev_whole(part), mode);
        if (ret)
-               goto out_put_whole;
+               return ret;
 
        ret = -ENXIO;
        if (!bdev_nr_sectors(part))
@@ -1306,9 +1304,7 @@ done:
        return 0;
 
 out_blkdev_put:
-       blkdev_put_whole(whole, mode);
-out_put_whole:
-       bdput(whole);
+       blkdev_put_whole(bdev_whole(part), mode);
        return ret;
 }
 
@@ -1321,7 +1317,6 @@ static void blkdev_put_part(struct block_device *part, fmode_t mode)
        blkdev_flush_mapping(part);
        whole->bd_disk->open_partitions--;
        blkdev_put_whole(whole, mode);
-       bdput(whole);
 }
 
 struct block_device *blkdev_get_no_open(dev_t dev)