From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752388AbaJFLdv (ORCPT ); Mon, 6 Oct 2014 07:33:51 -0400 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:59192 "EHLO e06smtp17.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752319AbaJFLdr (ORCPT ); Mon, 6 Oct 2014 07:33:47 -0400 Date: Mon, 6 Oct 2014 13:33:38 +0200 From: Cornelia Huck To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH 05/16] virtio: defer config changed notifications Message-ID: <20141006133338.236a1175.cornelia.huck@de.ibm.com> In-Reply-To: <1412525038-15871-6-git-send-email-mst@redhat.com> References: <1412525038-15871-1-git-send-email-mst@redhat.com> <1412525038-15871-6-git-send-email-mst@redhat.com> Organization: IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz =?UTF-8?B?R2VzY2jDpGZ0c2bDvGhydW5nOg==?= Dirk Wittkopp Sitz der Gesellschaft: =?UTF-8?B?QsO2Ymxpbmdlbg==?= Registergericht: Amtsgericht Stuttgart, HRB 243294 X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14100611-0542-0000-0000-000001123774 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 5 Oct 2014 19:07:05 +0300 "Michael S. Tsirkin" wrote: > Defer config changed notifications that arrive during > probe/scan/freeze/restore. > > This will allow drivers to set DRIVER_OK earlier, without worrying about > racing with config change interrupts. > > This change will also benefit old hypervisors (before 2009) > that send interrupts without checking DRIVER_OK: previously, > the callback could race with driver-specific initialization. > > This will also help simplify drivers. > > Signed-off-by: Michael S. Tsirkin > --- > include/linux/virtio.h | 6 ++++++ > drivers/virtio/virtio.c | 55 +++++++++++++++++++++++++++++++++++++++++-------- > 2 files changed, 52 insertions(+), 9 deletions(-) > > diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c > index 657f817..578e02d 100644 > --- a/drivers/virtio/virtio.c > +++ b/drivers/virtio/virtio.c > @@ -117,6 +117,40 @@ void virtio_check_driver_offered_feature(const struct virtio_device *vdev, > } > EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); > > +static void __virtio_config_changed(struct virtio_device *dev) > +{ > + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); > + > + if (!dev->config_enabled) > + dev->config_changed = true; > + else if (drv && drv->config_changed) > + drv->config_changed(dev); > +} > + > +void virtio_config_changed(struct virtio_device *dev) > +{ > + spin_lock_irq(&dev->config_lock); > + __virtio_config_changed(dev); > + spin_unlock_irq(&dev->config_lock); Hm, isn't this function called from the interrupt handler? > +} > +EXPORT_SYMBOL_GPL(virtio_config_changed); > + > +static void virtio_config_disable(struct virtio_device *dev) > +{ > + spin_lock_irq(&dev->config_lock); > + dev->config_enabled = false; > + spin_unlock_irq(&dev->config_lock); > +} > + > +static void virtio_config_enable(struct virtio_device *dev) > +{ > + spin_lock_irq(&dev->config_lock); > + dev->config_enabled = true; > + __virtio_config_changed(dev); > + dev->config_changed = false; > + spin_unlock_irq(&dev->config_lock); > +} > + Maybe call these virtio_config_change_{dis,en}able()? > static int virtio_dev_probe(struct device *_d) > { > int err, i;