From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753550Ab2DRSiJ (ORCPT ); Wed, 18 Apr 2012 14:38:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8693 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750721Ab2DRSiH (ORCPT ); Wed, 18 Apr 2012 14:38:07 -0400 Message-ID: <4F8F0A08.8010900@redhat.com> Date: Wed, 18 Apr 2012 20:38:00 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: "Michael S. Tsirkin" CC: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Amit Shah , Rusty Russell Subject: Re: [RFC PATCH] virtio_console: link vq to port with a private pointer in struct virtqueue References: <1334756013-11752-1-git-send-email-pbonzini@redhat.com> <20120418142146.GB11801@redhat.com> <4F8ED0E4.6000702@redhat.com> <20120418161028.GB12815@redhat.com> In-Reply-To: <20120418161028.GB12815@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 18/04/2012 18:10, Michael S. Tsirkin ha scritto: > On Wed, Apr 18, 2012 at 04:34:12PM +0200, Paolo Bonzini wrote: >> Il 18/04/2012 16:21, Michael S. Tsirkin ha scritto: >>>> @@ -1872,6 +1864,8 @@ static int virtcons_restore(struct virtio_device *vdev) >>>> list_for_each_entry(port, &portdev->ports, list) { >>>> port->in_vq = portdev->in_vqs[port->id]; >>>> port->out_vq = portdev->out_vqs[port->id]; >>>> + port->in_vq->vdev_priv = port; >>>> + port->out_vq->vdev_priv = port; >>>> >>>> fill_queue(port->in_vq, &port->inbuf_lock); >>>> >>> >>> Let's add an API to set this pointer. >>> Document that you must not set it after >>> probe/restore returned. >> >> Why? > > How would you prevent races if you do? With some lock in the driver. It's private to the driver, so the driver decides how to synchronize access. >>>> * @priv: a pointer for the virtqueue implementation to use. >>>> */ >>>> struct virtqueue { >>>> @@ -21,6 +22,7 @@ struct virtqueue { >>>> void (*callback)(struct virtqueue *vq); >>>> const char *name; >>>> struct virtio_device *vdev; >>>> + void *vdev_priv; >>>> void *priv; >>> >>> The name is confusing: it seems to imply it's a device pointer. >> >> ... it's private to the driver that owns vdev, hence the name. > > I own a car but I'm not called Michael Car :) > driver_priv might be ok too. unfortunately virtio-pci > is also a driver so it can be misunderstood. Yes. Is fixing the comment and keeping the vdev_priv name ok with you? > devices should dominate. ring is an implementation detail. Ring came first, ring gets the nice name. :) Paolo