fix unbalanced page refcounting in bio_map_user_iov
authorVitaly Mayatskikh <v.mayatskih@gmail.com>
Fri, 22 Sep 2017 05:18:39 +0000 (01:18 -0400)
committerAl Viro <viro@zeniv.linux.org.uk>
Wed, 11 Oct 2017 03:54:51 +0000 (23:54 -0400)
commit95d78c28b5a85bacbc29b8dba7c04babb9b0d467
tree171528916186018b071110eced6ebc55f5d6b3c3
parent899f0429c7d3eed886406cd72182bee3b96aa1f9
fix unbalanced page refcounting in bio_map_user_iov

bio_map_user_iov and bio_unmap_user do unbalanced pages refcounting if
IO vector has small consecutive buffers belonging to the same page.
bio_add_pc_page merges them into one, but the page reference is never
dropped.

Cc: stable@vger.kernel.org
Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
block/bio.c