[PATCH] block: do not leak memory in bio_copy_user_iov()

[jglisse]

From: JÃrÃme Glisse <jglisse@xxxxxxxxxx>

When bio_add_pc_page() fails in bio_copy_user_iov() we should free
the page we just allocated otherwise we are leaking it.

Signed-off-by: JÃrÃme Glisse <jglisse@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: linux-block@xxxxxxxxxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
 block/bio.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index b64cedc7f87c..716510ecd7ff 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1298,8 +1298,11 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
 			}
 		}
 
-		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
+		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) {
+			if (!map_data)
+				__free_page(page);
 			break;
+		}
 
 		len -= bytes;
 		offset = 0;
-- 
2.20.1