From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mail.bootlin.com ([62.4.15.54])
 by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux))
 id 1fZtcd-0005H4-Im
 for linux-mtd@lists.infradead.org; Mon, 02 Jul 2018 07:51:45 +0000
Date: Mon, 2 Jul 2018 09:51:21 +0200
From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Quentin Schulz <quentin.schulz@bootlin.com>, richard@nod.at,
 dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com,
 linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
 thomas.petazzoni@bootlin.com
Subject: Re: [PATCH v3 1/2] ubi: provide a way to skip CRC checks
Message-ID: <20180702095121.67bc61ef@bbrezillon>
In-Reply-To: <1530516625.469.82.camel@gmail.com>
References: <cover.6d66955e7c1848c8255870deb42eddb69bd276f3.1530169759.git-series.quentin.schulz@bootlin.com>
 <3f9cef553d4f5da3fe2d76113d79ada1f0fe5224.1530169759.git-series.quentin.schulz@bootlin.com>
 <1530516625.469.82.camel@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
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>

Hi Artem,

On Mon, 02 Jul 2018 10:30:25 +0300
Artem Bityutskiy <dedekind1@gmail.com> wrote:

> Hi,
> 
> On Thu, 2018-06-28 at 09:40 +0200, Quentin Schulz wrote:
> > diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
> > index d4b2e87..e9e9ecb 100644
> > --- a/drivers/mtd/ubi/kapi.c
> > +++ b/drivers/mtd/ubi/kapi.c
> > @@ -202,7 +202,7 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
> >  	desc->mode = mode;
> >  
> >  	mutex_lock(&ubi->ckvol_mutex);
> > -	if (!vol->checked) {
> > +	if (!vol->checked && !vol->skip_check) {
> >  		/* This is the first open - check the volume */
> >  		err = ubi_check_volume(ubi, vol_id);
> >  		if (err < 0) {  
> 
> Did you deliberately did not add a similar check to 'vol_cdev_write()' ?
> You want to skip checking on load but do have the checking after volume update ?

Yep, it's on purpose, I asked Quentin to keep the test on the update
volume path.

> Looks a bit inconsistent to me. At the very least deserves a comment in
> 'vol_cdev_write()' about why 'skip_check' flag is ignored there.

Well, I thought checking the CRC just after updating the volume made
sense, just to make sure things were written correctly on the medium.
Let's add a comment explaining why we keep the check here, unless you
see a strong reason to get rid of this check in the update path.

Regards,

Boris