Commit 61369905 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: move the bi_size overflow check in __bio_try_merge_page 



Checking for availability in bi_size in a function that attempts to
merge into an existing segment is a bit odd, as the limit also applies
when adding a new segment.  This code works fine as we always call
__bio_try_merge_page, but contributes to sub-optimal calling conventions
and doesn't lead to clear code.

Move it to two of the callers instead, the third one already has a more
strict check that includes max_hw_segments anyway.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJinyoung Choi <j-young.choi@samsung.com>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20230724165433.117645-6-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0eca8b6f

block/bio.c

+5 −4
Original line number Diff line number Diff line
@@ -949,10 +949,6 @@ static bool __bio_try_merge_page(struct bio *bio, struct page *page, 


	if (!page_is_mergeable(bv, page, len, off, same_page))

		return false;

	if (bio->bi_iter.bi_size > UINT_MAX - len) {

		*same_page = false;

		return false;

	}

	bv->bv_len += len;

	bio->bi_iter.bi_size += len;

	return true;
@@ -1123,6 +1119,8 @@ int bio_add_page(struct bio *bio, struct page *page, 


	if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))

		return 0;

	if (bio->bi_iter.bi_size > UINT_MAX - len)

		return 0;



	if (bio->bi_vcnt > 0 &&

	    __bio_try_merge_page(bio, page, len, offset, &same_page))
@@ -1204,6 +1202,9 @@ static int bio_iov_add_page(struct bio *bio, struct page *page, 
{

	bool same_page = false;



	if (WARN_ON_ONCE(bio->bi_iter.bi_size > UINT_MAX - len))

		return -EIO;



	if (bio->bi_vcnt > 0 &&

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

		if (same_page)