block: cache the partition index in struct block_device

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9941dc8..d29d1c7 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1451,6 +1451,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                bdev->bd_disk = disk;
                bdev->bd_queue = disk->queue;
                bdev->bd_contains = bdev;
+               bdev->bd_partno = partno;
 
                if (!partno) {
                        ret = -ENXIO;

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6e1fd5d..706dd3a 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -427,6 +427,7 @@ struct block_device {
 #endif
        struct block_device *   bd_contains;
        unsigned                bd_block_size;
+       u8                      bd_partno;
        struct hd_struct *      bd_part;
        /* number of times partitions within this device have been opened. */
        unsigned                bd_part_count;