bio_split() may error, so check this.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
 block/blk-merge.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index d813d799cee7..4cbccdbba638 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -107,17 +107,18 @@ static unsigned int bio_allowed_max_sectors(const struct queue_limits *lim)
 
 static struct bio *bio_submit_split(struct bio *bio, int split_sectors)
 {
-	if (unlikely(split_sectors < 0)) {
-		bio->bi_status = errno_to_blk_status(split_sectors);
-		bio_endio(bio);
-		return NULL;
-	}
+	if (unlikely(split_sectors < 0))
+		goto error;
 
 	if (split_sectors) {
 		struct bio *split;
 
 		split = bio_split(bio, split_sectors, GFP_NOIO,
 				&bio->bi_bdev->bd_disk->bio_split);
+		if (IS_ERR(split)) {
+			split_sectors = PTR_ERR(split);
+			goto error;
+		}
 		split->bi_opf |= REQ_NOMERGE;
 		blkcg_bio_issue_init(split);
 		bio_chain(split, bio);
@@ -128,6 +129,10 @@ static struct bio *bio_submit_split(struct bio *bio, int split_sectors)
 	}
 
 	return bio;
+error:
+	bio->bi_status = errno_to_blk_status(split_sectors);
+	bio_endio(bio);
+	return NULL;
 }
 
 struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim,
-- 
2.31.1