The incoming bio may be too big to be cloned into
one singlepage bvecs bio, so split the bio and
check the splitted bio one by one.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
 drivers/md/bcache/debug.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c
index 48d03e8b3385..18b2d2d138e3 100644
--- a/drivers/md/bcache/debug.c
+++ b/drivers/md/bcache/debug.c

@@ -103,7 +103,7 @@ void bch_btree_verify(struct btree *b)
 	up(&b->io_mutex);
 }
 
-void bch_data_verify(struct cached_dev *dc, struct bio *bio)
+static void __bch_data_verify(struct cached_dev *dc, struct bio *bio)
 {
 	char name[BDEVNAME_SIZE];
 	struct bio *check;

@@ -116,7 +116,7 @@ void bch_data_verify(struct cached_dev *dc, struct bio *bio)
 	 * in the new cloned bio because each single page need
 	 * to assign to each bvec of the new bio.
 	 */
-	check = bio_clone(bio, GFP_NOIO);
+	check = bio_clone_sp(bio, GFP_NOIO);
 	if (!check)
 		return;
 	check->bi_opf = REQ_OP_READ;

@@ -151,6 +151,26 @@ void bch_data_verify(struct cached_dev *dc, struct bio *bio)
 	bio_put(check);
 }
 
+void bch_data_verify(struct cached_dev *dc, struct bio *bio)
+{
+	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+	struct bio *clone = bio_clone_fast(bio, GFP_NOIO, q->bio_split);
+	unsigned sectors;
+
+	while (!bio_can_convert_to_sp(clone, &sectors)) {
+		struct bio *split = bio_split(clone, sectors,
+					      GFP_NOIO, q->bio_split);
+
+		__bch_data_verify(dc, split);
+		bio_put(split);
+	}
+
+	if (bio_sectors(clone))
+		__bch_data_verify(dc, clone);
+
+	bio_put(clone);
+}
+