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author | Michael S. Tsirkin <mst@redhat.com> | 2014-10-15 01:51:55 +0200 |
---|---|---|
committer | Rusty Russell <rusty@rustcorp.com.au> | 2014-10-15 01:54:56 +0200 |
commit | 22b7050a024d7deb0c9ef1e14ed73e3b1e369f24 (patch) | |
tree | be21b9a75aa1b5a95d8bb3ab7bf9470669e643bb | |
parent | virtio-pci: move freeze/restore to virtio core (diff) | |
download | linux-22b7050a024d7deb0c9ef1e14ed73e3b1e369f24.tar.xz linux-22b7050a024d7deb0c9ef1e14ed73e3b1e369f24.zip |
virtio: defer config changed notifications
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 <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cosmetic changes)
-rw-r--r-- | drivers/virtio/virtio.c | 58 | ||||
-rw-r--r-- | include/linux/virtio.h | 6 |
2 files changed, 55 insertions, 9 deletions
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 8216b7311092..df598dd8c5c8 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -117,6 +117,43 @@ 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_change_pending = true; + else if (drv && drv->config_changed) + drv->config_changed(dev); +} + +void virtio_config_changed(struct virtio_device *dev) +{ + unsigned long flags; + + spin_lock_irqsave(&dev->config_lock, flags); + __virtio_config_changed(dev); + spin_unlock_irqrestore(&dev->config_lock, flags); +} +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; + if (dev->config_change_pending) + __virtio_config_changed(dev); + dev->config_change_pending = false; + spin_unlock_irq(&dev->config_lock); +} + static int virtio_dev_probe(struct device *_d) { int err, i; @@ -153,6 +190,8 @@ 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 +202,8 @@ 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 +252,10 @@ 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_change_pending = 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 +284,13 @@ 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) @@ -297,6 +335,8 @@ int virtio_device_restore(struct virtio_device *dev) /* Finally, tell the device we're all set */ add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); + virtio_config_enable(dev); + return 0; } EXPORT_SYMBOL_GPL(virtio_device_restore); diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 8df7ba81e5c7..65261a7244fc 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_change_pending: 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_change_pending; + spinlock_t config_lock; struct device dev; struct virtio_device_id id; const struct virtio_config_ops *config; |