block: do not leak memory in bio_copy_user_iov()

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

Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: [email protected]
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Signed-off-by: Jérôme Glisse <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: Jérôme Glisse

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;