From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Wed, 26 Nov 2014 08:19:32 -0500 (EST)
From: Rodrigo Freire <rfreire@redhat.com>
To: Brian Norris <computersforpeace@gmail.com>
Message-ID: <1417070032.4547583.1417007972343.JavaMail.zimbra@redhat.com>
In-Reply-To: <20141126072147.GO3212@norris-Latitude-E6410>
References: <371358190.34795877.1410204429882.JavaMail.zimbra@redhat.com>
 <1444809468.34812041.1410206680931.JavaMail.zimbra@redhat.com>
 <20140909170231.GA14429@logfs.org>
 <1807144344.40128259.1410985683342.JavaMail.zimbra@redhat.com>
 <20141105202303.GN23619@ld-irv-0074>
 <2086372266.7454667.1415535533979.JavaMail.zimbra@redhat.com>
 <1874445287.7454806.1415535792984.JavaMail.zimbra@redhat.com>
 <20141126072147.GO3212@norris-Latitude-E6410>
Subject: Re: [PATCH v3 3/3] mtd: block2mtd: Removes PAGE_MASK as a index to
 partition size
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Cc: Felix Fietkau <nbd@openwrt.org>,
 =?utf-8?B?SsO2cm4=?= Engel <joern@logfs.org>,
 Herton Krzesinski <hkrzesin@redhat.com>, linux-kernel@vger.kernel.org,
 linux-mtd@lists.infradead.org, dwmw2@infradead.org
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>

From: "Brian Norris" <computersforpeace@gmail.com>
Sent: Wednesday, November 26, 2014 5:21:47 AM
Subject: Re: [PATCH v3 3/3] mtd: block2mtd: Removes PAGE_MASK as a index to
partition size

> On Sun, Nov 09, 2014 at 07:23:12AM -0500, Rodrigo Freire wrote:
> > PAGE_MASK is no longer needed with the new term.

> This isn't too descriptive. What you probably mean is that we assume the
> erase size is always larger than PAGE_SIZE.

> > This patch keeps the device size aligned with the erase_size.
> >
> > Signed-off-by: Felix Fietkau <nbd@openwrt.org>
> > Signed-off-by: Rodrigo Freire <rfreire@redhat.com>
> > Signed-off-by: Herton Krzesinski <herton@redhat.com>
> > ---
> > V3: Separated on a single patch
> > --- a/drivers/mtd/devices/block2mtd.c 2014-11-07 17:40:58.688747820 -02=
00
> > +++ b/drivers/mtd/devices/block2mtd.c 2014-11-07 17:41:28.054750893 -02=
00
> > @@ -291,8 +291,7 @@ static struct block2mtd_dev *add_device(
> > goto err_destroy_mutex;
> >
> > dev->mtd.name =3D name;
> > -
> > - dev->mtd.size =3D dev->blkdev->bd_inode->i_size & PAGE_MASK;
> > + dev->mtd.size =3D dev->blkdev->bd_inode->i_size & ~(erase_size - 1);

> You never guaranteed that erase_size is a power of two, so this doesn't
> necessarily mask the way you'd like...

> But also, why is this even necessary? I see that we should already have
> errored out if this was actually significant, since we have above:

> if ((long)dev->blkdev->bd_inode->i_size % erase_size) {
> pr_err("erasesize must be a divisor of device size\n");
> goto err_free_block2mtd;
> }

Hello Brian, and thanks for the review.

Honestly, I'd leave that untouched, but J=C3=B6rn pointed that it could be =
a issue at https://lkml.org/lkml/2014/9/9/680

I'd happily let it go without this patch 3, unless J=C3=B6rg wants to state=
 otherwise.