fs: simplify init_page_buffers

No need to convert from bdev to inode and back.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211018101130.1838532-11-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/buffer.c

@@ -897,7 +897,7 @@ init_page_buffers(struct page *page, struct block_device *bdev,
 	struct buffer_head *head = page_buffers(page);
 	struct buffer_head *bh = head;
 	int uptodate = PageUptodate(page);
-	sector_t end_block = blkdev_max_block(I_BDEV(bdev->bd_inode), size);
+	sector_t end_block = blkdev_max_block(bdev, size);
 
 	do {
 		if (!buffer_mapped(bh)) {