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: Christoph Hellwig <hch@xxxxxx>
---
block/bio.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 5d2c95e05b1a52..93e6bca3c2239f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -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))
@@ -1197,6 +1195,9 @@ 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)
--
2.39.2
