From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:48522)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1WxIAs-0004pf-7Z
	for qemu-devel@nongnu.org; Wed, 18 Jun 2014 11:53:28 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1WxIAl-0002BL-SH
	for qemu-devel@nongnu.org; Wed, 18 Jun 2014 11:53:21 -0400
Message-ID: <53A1B5DF.7020303@redhat.com>
Date: Wed, 18 Jun 2014 17:53:03 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
References: <1403105553-5478-1-git-send-email-ming.lei@canonical.com>	<20140618154335.GA25619@redhat.com>
	<CACVXFVPz8s9xcbSiqv4u4_QTmT+Ynz1o9eUtf5Tm3iepfWBa4g@mail.gmail.com>
In-Reply-To: <CACVXFVPz8s9xcbSiqv4u4_QTmT+Ynz1o9eUtf5Tm3iepfWBa4g@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH v1] virtio-scsi: fix object check failure
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: Ming Lei <ming.lei@canonical.com>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, qemu-devel@nongnu.org, Anthony Liguori <aliguori@amazon.com>, qemu-stable@nongnu.org

Il 18/06/2014 17:48, Ming Lei ha scritto:
> On Wed, Jun 18, 2014 at 11:43 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
>> On Wed, Jun 18, 2014 at 11:32:33PM +0800, Ming Lei wrote:
>>> In case of vhost-scsi, the object type of VirtIODevice isn't
>>> VirtIOSCSI, so use the cast trick to fix the problem like
>>> in virtio_scsi_handle_cmd().
>>>
>>> Also 'events_dropped' need to be accessed in the path,
>>
>> in which path?
>
> I mean vq's notify path, virtio_scsi_handle_event().

A better way is this:

- create a VirtIOSCSICommonClass struct and use it (virtio_scsi_common_info)

- add three members virtio_scsi_handle_ctrl, virtio_scsi_handle_event, 
virtio_scsi_handle_cmd to VirtIOSCSICommonClass

- initialize them to the existing functions in virtio_scsi_class_init

- initialize them to dummy empty functions in vhost_scsi_class_init

Which I should have done in the first place when rebasing vhost-scsi, 
and I didn't only because I was lazy and thought this could not happen. 
:(  Turns out it only didn't because at the time the kernel did not 
support events.

Paolo