alloc_behind_master_bio() can possibly add multiple pages to a bio, but it
is not checking for the return value of bio_add_page() if adding really
succeeded.

Check if the page adding succeeded and if not bail out.

Signed-off-by: Johannes Thumshirn <redacted>
Reviewed-by: Damien Le Moal <redacted>
---
 drivers/md/raid1.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 68a9e2d9985b..bd7c339a84a1 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c

@@ -1147,7 +1147,8 @@ static void alloc_behind_master_bio(struct r1bio *r1_bio,
                if (unlikely(!page))
                        goto free_pages;

-               bio_add_page(behind_bio, page, len, 0);
+               if (!bio_add_page(behind_bio, page, len, 0))
+                       goto free_pages;