From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752222AbaJEQHF (ORCPT ); Sun, 5 Oct 2014 12:07:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63491 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751882AbaJEQDj (ORCPT ); Sun, 5 Oct 2014 12:03:39 -0400 Date: Sun, 5 Oct 2014 19:07:05 +0300 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Rusty Russell , Heinz Graalfs , virtualization@lists.linux-foundation.org Subject: [PATCH 05/16] virtio: defer config changed notifications Message-ID: <1412525038-15871-6-git-send-email-mst@redhat.com> References: <1412525038-15871-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1412525038-15871-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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/include/linux/virtio.h b/include/linux/virtio.h index 8df7ba8..5636b11 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -79,6 +79,9 @@ bool virtqueue_is_broken(struct virtqueue *vq); * virtio_device - representation of a device using virtio * @index: unique position on the virtio bus * @failed: saved value for CONFIG_S_FAILED bit (for restore) + * @config_enabled: configuration change reporting enabled + * @config_changed: configuration change reported while disabled + * @config_lock: protects configuration change reporting * @dev: underlying device. * @id: the device type identification (used to match it with a driver). * @config: the configuration ops for this device. @@ -90,6 +93,9 @@ bool virtqueue_is_broken(struct virtqueue *vq); struct virtio_device { int index; bool failed; + bool config_enabled; + bool config_changed; + spinlock_t config_lock; struct device dev; struct virtio_device_id id; const struct virtio_config_ops *config; 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); +} +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); +} + static int virtio_dev_probe(struct device *_d) { int err, i; @@ -153,6 +187,8 @@ static int virtio_dev_probe(struct device *_d) add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); if (drv->scan) drv->scan(dev); + + virtio_config_enable(dev); } return err; @@ -163,6 +199,8 @@ static int virtio_dev_remove(struct device *_d) struct virtio_device *dev = dev_to_virtio(_d); struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + virtio_config_disable(dev); + drv->remove(dev); /* Driver should have reset device. */ @@ -211,6 +249,10 @@ int register_virtio_device(struct virtio_device *dev) dev->index = err; dev_set_name(&dev->dev, "virtio%u", dev->index); + spin_lock_init(&dev->config_lock); + dev->config_enabled = false; + dev->config_changed = false; + /* We always start by resetting the device, in case a previous * driver messed it up. This also tests that code path a little. */ dev->config->reset(dev); @@ -239,20 +281,13 @@ void unregister_virtio_device(struct virtio_device *dev) } EXPORT_SYMBOL_GPL(unregister_virtio_device); -void virtio_config_changed(struct virtio_device *dev) -{ - struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); - - if (drv && drv->config_changed) - drv->config_changed(dev); -} -EXPORT_SYMBOL_GPL(virtio_config_changed); - #ifdef CONFIG_PM_SLEEP int virtio_device_freeze(struct virtio_device *dev) { struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + virtio_config_disable(dev); + dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED; if (drv && drv->freeze) @@ -296,6 +331,8 @@ int virtio_device_restore(struct virtio_device *dev) add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); } + virtio_config_enable(dev); + return 0; } EXPORT_SYMBOL_GPL(virtio_device_restore); -- MST