From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mga01.intel.com ([192.55.52.88])
 by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux))
 id 1XC1iR-0002sh-Ne
 for linux-mtd@lists.infradead.org; Tue, 29 Jul 2014 07:20:56 +0000
Message-ID: <1406618431.23376.81.camel@sauron.fi.intel.com>
Subject: Re: [PATCH v2] ubifs: refactor ubifs_file_mmap()
From: Artem Bityutskiy <dedekind1@gmail.com>
Reply-To: dedekind1@gmail.com
To: Zhang Zhen <zhenzhang.zhang@huawei.com>
Date: Tue, 29 Jul 2014 10:20:31 +0300
In-Reply-To: <53D71A0F.9070008@huawei.com>
References: <1406010548-13996-1-git-send-email-zhenzhang.zhang@huawei.com>
 <53CE049B.7050801@huawei.com>
 <1406564713.23376.39.camel@sauron.fi.intel.com>
 <53D71A0F.9070008@huawei.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Cc: wangnan0@huawei.com, MTD Maling List <linux-mtd@lists.infradead.org>,
 Adrian Hunter <adrian.hunter@intel.com>
List-Id: Linux MTD discussion mailing list <linux-mtd.lists.infradead.org>
List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-mtd>,
 <mailto:linux-mtd-request@lists.infradead.org?subject=unsubscribe>
List-Archive: <http://lists.infradead.org/pipermail/linux-mtd/>
List-Post: <mailto:linux-mtd@lists.infradead.org>
List-Help: <mailto:linux-mtd-request@lists.infradead.org?subject=help>
List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-mtd>,
 <mailto:linux-mtd-request@lists.infradead.org?subject=subscribe>

On Tue, 2014-07-29 at 11:50 +0800, Zhang Zhen wrote:
> On 2014/7/29 0:25, Artem Bityutskiy wrote:
> > On Tue, 2014-07-22 at 14:28 +0800, Zhang Zhen wrote:
> >> generic_file_mmap() set vma->vm_ops = &generic_file_vm_ops,
> >> then ubifs_file_mmap set vma->vm_ops = &ubifs_file_vm_ops.
> >> So it is redundant.
> >> And there is no kind of file does not supply page reading function
> >> in ubifs. The readpage() check up for mmap file in generic_file_mmap()
> >> is not needed.
> >>
> >> So remove the call of generic_file_mmap().
> >>
> >> Change v1 -> v2:
> >> - deleted the mapping variable
> >> Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
> > 
> > Hi, I am not sure about this patch. 'generic_file_mmap()' covers !
> > CONFIG_MMU case too, for example.
> > 
> Yes, I missed that. We can add #ifdef CONFIG_MMU in ubifs_file_mmap().
> Considering the patch itself is not important changes, we can give up
> this patch, remain the same.
> 
> What do you think?

I think it is better to leave it as it is, because that's not too bad
and works. Changing this has a risk of breaking something. UBIFS does
not enjoy a huge user base like, say, ext4, so the breakage could easily
go unnoticed for long time.

-- 
Best Regards,
Artem Bityutskiy