block: fix "check bi_size overflow before merge"

This partially reverts commit e3a5d8e. Commit e3a5d8e ("check bi_size overflow before merge") adds a bio_full check to __bio_try_merge_page. This will cause __bio_try_merge_page to fail when the last bi_io_vec has been reached. Instead, what we want here is only the bi_size overflow check. Fixes: e3a5d8e ("block: check bi_size overflow before merge") Cc: [email protected] # v5.4+ Reviewed-by: Ming Lei <[email protected]> Signed-off-by: Andreas Gruenbacher <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
dabrace · Dec 10, 2019 · cc90bc6 · cc90bc6
1 parent dc3ecfc
commit cc90bc6
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/block/bio.c b/block/bio.c
@@ -754,10 +754,12 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
 	if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
 		return false;
 
-	if (bio->bi_vcnt > 0 && !bio_full(bio, len)) {
+	if (bio->bi_vcnt > 0) {
 		struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
 
 		if (page_is_mergeable(bv, page, len, off, same_page)) {
+			if (bio->bi_iter.bi_size > UINT_MAX - len)
+				return false;
 			bv->bv_len += len;
 			bio->bi_iter.bi_size += len;
 			return true;