[PATCH 4.19 071/101] block: do not leak memory in bio_copy_user_iov()

[Greg Kroah-Hartman]

From: Jérôme Glisse <jgli...@redhat.com>

commit a3761c3c91209b58b6f33bf69dd8bb8ec0c9d925 upstream.

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: linux-bl...@vger.kernel.org
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: sta...@vger.kernel.org
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulka...@wdc.com>
Signed-off-by: Jérôme Glisse <jgli...@redhat.com>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 block/bio.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/block/bio.c
+++ b/block/bio.c
@@ -1240,8 +1240,11 @@ struct bio *bio_copy_user_iov(struct req
                        }
                }
 
-               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;