From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752893AbbCPLfJ (ORCPT ); Mon, 16 Mar 2015 07:35:09 -0400 Received: from mail-pa0-f49.google.com ([209.85.220.49]:36643 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751170AbbCPLfF (ORCPT ); Mon, 16 Mar 2015 07:35:05 -0400 From: Omar Sandoval To: Alexander Viro , linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org, osd-dev@open-osd.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, fuse-devel@lists.sourceforge.net, cluster-devel@redhat.com, jfs-discussion@lists.sourceforge.net, HPDD-discuss@ml01.01.org, linux-nfs@vger.kernel.org, linux-nilfs@vger.kernel.org, ocfs2-devel@oss.oracle.com, reiserfs-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, xfs@oss.sgi.com Cc: linux-kernel@vger.kernel.org, Chris Mason , Josef Bacik , David Sterba , "Yan Zheng" , Sage Weil , Steve French , Boaz Harrosh , Benny Halevy , Jan Kara , "Theodore Ts'o" , Andreas Dilger , Jaegeuk Kim , Changman Lee , Miklos Szeredi , Steven Whitehouse , Dave Kleikamp , Oleg Drokin , Trond Myklebust , Anna Schumaker , Ryusuke Konishi , Mark Fasheh , Joel Becker , Eric Van Hensbergen , Ron Minnich , Latchesar Ionkov , Dave Chinner , Omar Sandoval Subject: [RFC PATCH 0/5] Remove rw parameter from direct_IO() Date: Mon, 16 Mar 2015 04:33:48 -0700 Message-Id: X-Mailer: git-send-email 2.3.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Al, here's some cleanup that you mentioned back in December that I got around to (https://lkml.org/lkml/2014/12/15/28). In summary, the rw parameter to a_ops->direct_IO() is redundant with .type in struct iov_iter. Additionally, rw is inconsistently checked for being a WRITE; some filesystems do rw == WRITE, others do rw & WRITE, and others do both within the same function :) The distinction is that swapout may OR in the ITER_BVEC flag in the rw passed to ->direct_IO(), so the two are not equivalent (although this really only happens for swap-over-NFS, but it's scary nonetheless). After looking through all of these, it definitely looks like every check means for ANY write, not just non-kernel writes. So, the solution presented here is: - Add a helper, iov_iter_rw(), which always returns either READ or WRITE, no ITER_.* or REQ_.* nonsense mixed in. For consistency, the return value is always checked for equality - Get rid of all uses of rw in any implementations of direct_IO, starting with the generic code - Nuke the actual parameter and update the documentation I decided to squish all of the filesystems together in patch 4 to avoid inundating the mailing lists with 20+ mostly two-line patches, but I can split those out if that's any better. Additionally, patch 1 pulls fs.h into uio.h, which seems undesirable. These were mostly just compile tested, with a couple of direct I/O xfstests run on btrfs as quick sanity check, so getting some more eyes on is probably a good thing. They should apply on top of v4.0-rc4. Please comment away. Thank you, Omar Sandoval (5): new helper: iov_iter_rw() Remove rw from {,__,do_}blockdev_direct_IO() Remove rw from dax_{do_,}io() direct_IO: use iov_iter_rw() instead of rw everywhere direct_IO: remove rw from a_ops->direct_IO() Documentation/filesystems/Locking | 2 +- Documentation/filesystems/vfs.txt | 2 +- drivers/staging/lustre/lustre/llite/rw26.c | 22 ++++++++--------- fs/9p/vfs_addr.c | 2 +- fs/affs/file.c | 9 +++---- fs/block_dev.c | 8 +++--- fs/btrfs/inode.c | 24 +++++++++--------- fs/ceph/addr.c | 3 +-- fs/cifs/file.c | 3 +-- fs/dax.c | 27 ++++++++++----------- fs/direct-io.c | 39 ++++++++++++++---------------- fs/exofs/inode.c | 4 +-- fs/ext2/inode.c | 11 ++++----- fs/ext3/inode.c | 14 +++++------ fs/ext4/ext4.h | 4 +-- fs/ext4/indirect.c | 25 ++++++++++--------- fs/ext4/inode.c | 28 ++++++++++----------- fs/f2fs/data.c | 22 ++++++++--------- fs/fat/inode.c | 9 +++---- fs/fuse/file.c | 16 ++++++------ fs/gfs2/aops.c | 16 ++++++------ fs/hfs/inode.c | 8 +++--- fs/hfsplus/inode.c | 9 +++---- fs/jfs/inode.c | 8 +++--- fs/nfs/direct.c | 4 +-- fs/nilfs2/inode.c | 10 +++----- fs/ocfs2/aops.c | 22 +++++++---------- fs/reiserfs/inode.c | 8 +++--- fs/udf/file.c | 3 +-- fs/udf/inode.c | 7 +++--- fs/xfs/xfs_aops.c | 12 ++++----- include/linux/fs.h | 24 +++++++++--------- include/linux/nfs_fs.h | 2 +- include/linux/uio.h | 10 ++++++++ mm/filemap.c | 4 +-- mm/page_io.c | 4 +-- 36 files changed, 206 insertions(+), 219 deletions(-) -- 2.3.3