Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754594AbcDNMDQ (ORCPT ); Thu, 14 Apr 2016 08:03:16 -0400 Received: from mail-oi0-f65.google.com ([209.85.218.65]:34037 "EHLO mail-oi0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754370AbcDNMDL (ORCPT ); Thu, 14 Apr 2016 08:03:11 -0400 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, Christoph Hellwig , Ming Lei , Al Viro , Andreas Dilger , Andrew Morton , devel@driverdev.osuosl.org (open list:STAGING SUBSYSTEM), dm-devel@redhat.com (open list:DEVICE-MAPPER (LVM)), drbd-dev@lists.linbit.com (open list:DRBD DRIVER), Frank Zago , Greg Kroah-Hartman , Hannes Reinecke , James Simmons , Jan Kara , Jarod Wilson , Jiri Kosina , Joe Perches , "John L. Hammond" , Julia Lawall , Keith Busch , Kent Overstreet , "Kirill A. Shutemov" , linux-bcache@vger.kernel.org (open list:BCACHE (BLOCK LAYER CACHE)), linux-mm@kvack.org (open list:MEMORY MANAGEMENT), linux-pm@vger.kernel.org (open list:HIBERNATION (aka Software Suspend, aka swsusp)), linux-raid@vger.kernel.org (open list:SOFTWARE RAID (Multiple Disks) SUPPORT), linux-scsi@vger.kernel.org (open list:TARGET SUBSYSTEM), logfs@logfs.org (open list:LogFS), lustre-devel@lists.lustre.org (moderated list:STAGING - LUSTRE PARALLEL FILESYSTEM), Mike Rapoport , Mike Snitzer , Miklos Szeredi , Minchan Kim , NeilBrown , NeilBrown , Oleg Drokin , "Rafael J. Wysocki" , Rasmus Villemoes , Swee Hua Law , target-devel@vger.kernel.org (open list:TARGET SUBSYSTEM), Tejun Heo Subject: [PATCH v1 00/27] block: cleanup direct access to .bi_vcnt & .bi_io_vec Date: Thu, 14 Apr 2016 20:02:18 +0800 Message-Id: <1460635375-28282-1-git-send-email-tom.leiming@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4647 Lines: 110 Hi Guys, It is always not a good practice to access bio->bi_vcnt and bio->bi_io_vec from drivers directly. Also this kind of direct access will cause trouble when converting to multipage bvecs because currently drivers may suppose one bvec always include one page, and use the two fields to figure out how to handle pages. Even the actual meaning of the two fields arn't change from block subsystem's view, but it may change from driver or fs's view, so this patchset takes a conservative approach to cleanup direct access to the two fields for avoiding regressions. The 1st patch introduces the following 3 bio helpers which can be used inside drivers for avoiding direct access to .bi_vcnt and .bi_io_vec. bio_pages() bio_get_base_vec() bio_set_vec_table() bio_pages() can be easy to convert to multipage bvecs. For bio_get_base_vec() and bio_set_vec_table(), they are often used during initializing a new bio or in case of single bvec bio. With the two new helpers, it becomes quite easy to audit access to .bi_io_vec and .bi_vcnt. Most of the other patches use the 3 helpers to clean up most of direct access to .bi_vcnt and .bi_io_vec from drivers, except for MD and btrfs, which two subsystems will be handled with different way in future. For btrfs, its direct access to .bi_vcnt & .bi_io_vec need to be cleanuped and audited that there isn't issue once converting to multipage bvecs. For raid(md), given its usage is quite complicated, we can just not enable multipage bvecs for raid queue until all its usage are cleaned up and audited. So it won't be a blocker for multipage bvecs. Also bio_add_page() is used in floppy, dm-crypt and fs/logfs to avoiding direct access to .bi_vcnt & .bi_io_vec. The patchset can be found in the following tree: https://github.com/ming1/linux/tree/v4.6-rc-block-next-mpbvecs-cleanup.v1 V1: - add Reviewed-by - remove bio_is_full() helper because target can find it via the return value of bio_add_pc_page() (9/27) - add comment on another two uses of bio_get_base_vec() (16/27) - rebased on latest for-next branch of block tree Ming Lei (27): block: bio: introduce 3 helpers for cleanup block: drbd: use bio_get_base_vec() to retrieve the 1st bvec block: drbd: remove impossible failure handling block: loop: use bio_get_base_vec() to retrive bvec table block: pktcdvd: use bio_get_base_vec() to retrive bvec table block: floppy: use bio_set_vec_table() block: floppy: use bio_add_page() staging: lustre: avoid to use bio->bi_vcnt directly target: avoid to access .bi_vcnt directly bcache: debug: avoid to access .bi_io_vec directly bcache: io.c: use bio_set_vec_table bcache: journal.c: use bio_set_vec_table() bcache: movinggc: use bio_set_vec_table() bcache: writeback: use bio_set_vec_table() bcache: super: use bio_set_vec_table() bcache: super: use bio_get_base_vec dm: crypt: use bio_add_page() dm: dm-io.c: use bio_get_base_vec() dm: dm.c: replace 'bio->bi_vcnt == 1' with !bio_multiple_segments dm: dm-bufio.c: use bio_set_vec_table() fs: logfs: use bio_set_vec_table() fs: logfs: convert to bio_add_page() in sync_request() fs: logfs: use bio_add_page() in __bdev_writeseg() fs: logfs: use bio_add_page() in do_erase() fs: logfs: remove unnecesary check kernel/power/swap.c: use bio_get_base_vec() mm: page_io.c: use bio_get_base_vec() drivers/block/drbd/drbd_bitmap.c | 4 +- drivers/block/drbd/drbd_receiver.c | 14 +--- drivers/block/floppy.c | 9 +-- drivers/block/loop.c | 5 +- drivers/block/pktcdvd.c | 3 +- drivers/md/bcache/debug.c | 11 ++- drivers/md/bcache/io.c | 3 +- drivers/md/bcache/journal.c | 3 +- drivers/md/bcache/movinggc.c | 6 +- drivers/md/bcache/super.c | 33 ++++++--- drivers/md/bcache/writeback.c | 4 +- drivers/md/dm-bufio.c | 3 +- drivers/md/dm-crypt.c | 8 +-- drivers/md/dm-io.c | 7 +- drivers/md/dm.c | 3 +- drivers/staging/lustre/lustre/llite/lloop.c | 9 +-- drivers/target/target_core_pscsi.c | 8 +-- fs/logfs/dev_bdev.c | 107 +++++++++++----------------- include/linux/bio.h | 21 ++++++ kernel/power/swap.c | 10 ++- mm/page_io.c | 18 ++++- 21 files changed, 155 insertions(+), 134 deletions(-) Thanks, Ming -- 1.9.1