From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-fsdevel-owner@vger.kernel.org>
Received: from mx2.suse.de ([195.135.220.15]:34771 "EHLO mx2.suse.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751223AbeC3IWX (ORCPT <rfc822;linux-fsdevel@vger.kernel.org>);
        Fri, 30 Mar 2018 04:22:23 -0400
Date: Fri, 30 Mar 2018 10:22:21 +0200
From: Jan Kara <jack@suse.cz>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>, linux-nvdimm <linux-nvdimm@lists.01.org>,
        Jeff Moyer <jmoyer@redhat.com>,
        Matthew Wilcox <mawilcox@microsoft.com>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        Christoph Hellwig <hch@lst.de>, david <david@fromorbit.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        linux-xfs <linux-xfs@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 07/14] fs, dax: use page->mapping to warn if truncate
 collides with a busy page
Message-ID: <20180330082221.cea5hz7kq3gyg7w5@quack2.suse.cz>
References: <152167302988.5268.4370226749268662682.stgit@dwillia2-desk3.amr.corp.intel.com>
 <152167306807.5268.8483232024444414342.stgit@dwillia2-desk3.amr.corp.intel.com>
 <20180329160215.glnrmyunujcc4vwg@quack2.suse.cz>
 <CAPcyv4jK92ev=yWaKCUdxN5z+4+feH+ts3j6KHk57bZVu_QqYQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAPcyv4jK92ev=yWaKCUdxN5z+4+feH+ts3j6KHk57bZVu_QqYQ@mail.gmail.com>
Sender: linux-fsdevel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

On Thu 29-03-18 16:02:45, Dan Williams wrote:
> On Thu, Mar 29, 2018 at 9:02 AM, Jan Kara <jack@suse.cz> wrote:
> > On Wed 21-03-18 15:57:48, Dan Williams wrote:
> [..]
> > I find it quite tricky that in case we pass zero page / empty entry into
> > dax_[dis]associate_entry(), it will not do anything because
> > dax_entry_size() will return 0. Can we add an explicit check into
> > dax_[dis]associate_entry() or at least a comment there?
> 
> How about the following, i.e. rename the loop helper to
> for_each_dax_pfn() to make it clearer that we're only operating on
> mapped pfns, and also add a comment to indicate the same:
> 
> /*
>  * Iterate through all mapped pfns represented by an entry, i.e. skip
>  * 'empty' and 'zero' entries.
>  */
> #define for_each_dax_pfn(entry, pfn) \
>         for (pfn = dax_radix_pfn(entry); \
>                         pfn < dax_radix_end_pfn(entry); pfn++)

Maybe call it for_each_mapped_pfn()? Other than that it looks fine to me.

								Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR