Commit 34cdb8c8 authored by Keith Busch's avatar Keith Busch Committed by Jens Axboe
Browse files

block: ensure bio_iov_add_page can't fail 



Adding the page could fail on the bio_full() condition, which checks for
either exceeding the bio's max segments or total size exceeding
UINT_MAX. We already ensure the max segments can't be exceeded, so just
ensure the total size won't reach the limit. This simplifies error
handling and removes unnecessary repeated bio_full() checks.

Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20220712153256.2202024-2-kbusch@fb.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 325347d9

block/bio.c

+9 −10
Original line number Diff line number Diff line
@@ -1165,8 +1165,6 @@ static int bio_iov_add_page(struct bio *bio, struct page *page, 
	bool same_page = false;



	if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {

		if (WARN_ON_ONCE(bio_full(bio, len)))

			return -EINVAL;

		__bio_add_page(bio, page, len, offset);

		return 0;

	}
@@ -1228,7 +1226,8 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) 
	 * result to ensure the bio's total size is correct. The remainder of

	 * the iov data will be picked up in the next bio iteration.

	 */

	size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);

	size = iov_iter_get_pages(iter, pages, UINT_MAX - bio->bi_iter.bi_size,

				  nr_pages, &offset);

	if (size > 0)

		size = ALIGN_DOWN(size, bdev_logical_block_size(bio->bi_bdev));

	if (unlikely(size <= 0))
@@ -1238,16 +1237,16 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) 
		struct page *page = pages[i];



		len = min_t(size_t, PAGE_SIZE - offset, left);

		if (bio_op(bio) == REQ_OP_ZONE_APPEND)

		if (bio_op(bio) == REQ_OP_ZONE_APPEND) {

			ret = bio_iov_add_zone_append_page(bio, page, len,

					offset);

		else

			ret = bio_iov_add_page(bio, page, len, offset);



			if (ret) {

				bio_put_pages(pages + i, left, offset);

				break;

			}

		} else

			bio_iov_add_page(bio, page, len, offset);



		offset = 0;

	}