[PATCH AUTOSEL 5.15 34/47] block: prevent an integer overflow in bvec_try_merge_hw_page

[Sasha Levin]

From: Christoph Hellwig <hch@xxxxxx>

[ Upstream commit 3f034c374ad55773c12dd8f3c1607328e17c0072 ]

Reordered a check to avoid a possible overflow when adding len to bv_len.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Link: https://lore.kernel.org/r/20231204173419.782378-2-hch@xxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 block/bio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index ba9120d4fe49..8bd74ec45ac8 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -809,7 +809,7 @@ static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio,
 
 	if ((addr1 | mask) != (addr2 | mask))
 		return false;
-	if (bv->bv_len + len > queue_max_segment_size(q))
+	if (len > queue_max_segment_size(q) - bv->bv_len)
 		return false;
 	return __bio_try_merge_page(bio, page, len, offset, same_page);
 }
-- 
2.43.0