block: add a sb_bdev_nr_blocks helper

Add a helper to return the size of sb->s_bdev in sb->s_blocksize_bits
based unites.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index b560aee1d69f088697d477fca1360bafb11d0143..7a48d3ac725f3596ed75e14bc53d4322b9850282 100644 (file)
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -250,6 +250,12 @@ static inline sector_t get_capacity(struct gendisk *disk)
        return bdev_nr_sectors(disk->part0);
 }
 
+static inline u64 sb_bdev_nr_blocks(struct super_block *sb)
+{
+       return bdev_nr_sectors(sb->s_bdev) >>
+               (sb->s_blocksize_bits - SECTOR_SHIFT);
+}
+
 int bdev_disk_changed(struct gendisk *disk, bool invalidate);
 void blk_drop_partitions(struct gendisk *disk);