From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:38382)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <B43198@freescale.com>) id 1Yf1GT-0000mI-NY
	for qemu-devel@nongnu.org; Mon, 06 Apr 2015 03:16:10 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <B43198@freescale.com>) id 1Yf1GQ-00083x-J6
	for qemu-devel@nongnu.org; Mon, 06 Apr 2015 03:16:09 -0400
Received: from mail-bn1on0143.outbound.protection.outlook.com
	([157.56.110.143]:33466
	helo=na01-bn1-obe.outbound.protection.outlook.com)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <B43198@freescale.com>) id 1Yf1GQ-00083j-Bx
	for qemu-devel@nongnu.org; Mon, 06 Apr 2015 03:16:06 -0400
Message-ID: <55223284.3090501@freescale.com>
Date: Mon, 6 Apr 2015 10:15:16 +0300
From: Purcareata Bogdan <b43198@freescale.com>
MIME-Version: 1.0
References: <1428058914-32050-1-git-send-email-bogdan.purcareata@freescale.com>
	<551EA099.4070702@redhat.com> <551EA74F.5030906@msgid.tls.msk.ru>
In-Reply-To: <551EA74F.5030906@msgid.tls.msk.ru>
Content-Type: text/plain; charset="windows-1252"; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH] nbd/trivial: fix type cast for ioctl
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Michael Tokarev <mjt@tls.msk.ru>, Paolo Bonzini <pbonzini@redhat.com>, Bogdan Purcareata <bogdan.purcareata@freescale.com>, qemu-devel@nongnu.org, qemu-stable <qemu-stable@nongnu.org>

On 03.04.2015 17:44, Michael Tokarev wrote:
> 03.04.2015 17:15, Paolo Bonzini wrote:
>> On 03/04/2015 13:01, Bogdan Purcareata wrote:
> ...
>>> -    if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / (size_t)BDRV_SECTOR_SIZE) < 0) {
>>> +    if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE) < 0)) {
>>>           int serrno = errno;
>
> Hmm..  I don't think this is right at all.  Now we compare size_t with zero,
> the result is always false, and set error if ioctl return anything other than 0,
> including any positive value.
>
> Compare:
>
>    if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE) < 0))
>    if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0)
>
> I think the latter is the right version.

Yes, the latter is indeed the right version. Great catch!

> So much for trivial... ;)

Me and my slippery fingers. Sorry for the mishap.

Bogdan P.

> Thanks,
>
> /mjt
>