Use the sb_bdev_nr_blocks helper instead of open coding it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Link: https://lore.kernel.org/r/20211018101130.1838532-28-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>