From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754226AbcEBPps (ORCPT ); Mon, 2 May 2016 11:45:48 -0400 Received: from mail.kernel.org ([198.145.29.136]:60893 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752589AbcEBPpk (ORCPT ); Mon, 2 May 2016 11:45:40 -0400 Message-ID: <1462203935.11211.15.camel@kernel.org> Subject: Re: [PATCH v4 5/7] fs: prioritize and separate direct_io from dax_io From: Vishal Verma To: Christoph Hellwig , Vishal Verma Cc: linux-nvdimm@ml01.01.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, xfs@oss.sgi.com, linux-ext4@vger.kernel.org, linux-mm@kvack.org, Matthew Wilcox , Ross Zwisler , Dan Williams , Dave Chinner , Jan Kara , Jens Axboe , Al Viro , Andrew Morton , linux-kernel@vger.kernel.org, Jeff Moyer Date: Mon, 02 May 2016 09:45:35 -0600 In-Reply-To: <20160502145606.GD20589@infradead.org> References: <1461878218-3844-1-git-send-email-vishal.l.verma@intel.com> <1461878218-3844-6-git-send-email-vishal.l.verma@intel.com> <20160502145606.GD20589@infradead.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2 (3.18.5.2-1.fc23) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2016-05-02 at 07:56 -0700, Christoph Hellwig wrote: > > > > index 79defba..97a1f5f 100644 > > --- a/fs/block_dev.c > > +++ b/fs/block_dev.c > > @@ -167,12 +167,21 @@ blkdev_direct_IO(struct kiocb *iocb, struct > > iov_iter *iter, loff_t offset) > >   struct file *file = iocb->ki_filp; > >   struct inode *inode = bdev_file_inode(file); > >   > > - if (IS_DAX(inode)) > > + if (iocb_is_direct(iocb)) > > + return __blockdev_direct_IO(iocb, inode, > > I_BDEV(inode), iter, > > +     offset, > > blkdev_get_block, NULL, > > +     NULL, > > DIO_SKIP_DIO_COUNT); > > + else if (iocb_is_dax(iocb)) > >   return dax_do_io(iocb, inode, iter, offset, > > blkdev_get_block, > >   NULL, DIO_SKIP_DIO_COUNT); > > - return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), > > iter, offset, > > -     blkdev_get_block, NULL, NULL, > > -     DIO_SKIP_DIO_COUNT); > > + else { > > + /* > > +  * If we're in the direct_IO path, either the > > IOCB_DIRECT or > > +  * IOCB_DAX flags must be set. > > +  */ > > + WARN_ONCE(1, "Kernel Bug with iocb flags\n"); > > + return -ENXIO; > > + } > DAX should not even end up in ->direct_IO. Do you mean to say remove the last 'else' clause entirely? I agree that it should never be hit, which is why it is a WARN.. But I'm happy to remove it. > > > > > --- a/fs/xfs/xfs_file.c > > +++ b/fs/xfs/xfs_file.c > > @@ -300,7 +300,7 @@ xfs_file_read_iter( > >   > >   XFS_STATS_INC(mp, xs_read_calls); > >   > > - if (unlikely(iocb->ki_flags & IOCB_DIRECT)) > > + if (unlikely(iocb->ki_flags & (IOCB_DIRECT | IOCB_DAX))) > >   ioflags |= XFS_IO_ISDIRECT; > please also add a XFS_IO_ISDAX flag to propagate the information > properly and allow tracing to display the actual I/O type. Will do. > > > > > +static inline bool iocb_is_dax(struct kiocb *iocb) > >  { > > + return IS_DAX(file_inode(iocb->ki_filp)) && > > + (iocb->ki_flags & IOCB_DAX); > > +} > > + > > +static inline bool iocb_is_direct(struct kiocb *iocb) > > +{ > > + return iocb->ki_flags & IOCB_DIRECT; > >  } > No need for these helpers - especially as IOCB_DAX should never be > set > if IS_DAX is false. Ok. So check the flags directly where needed? > -- > To unsubscribe from this list: send the line "unsubscribe linux- > block" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html