[PATCH RFC 1/3] virtio: add notify() callback to virtio_driver

[Heinz Graalfs]

Add an optional notify() callback to virtio_driver. A backend
driver can provide this callback to perform actions for a lost
device.

notify() event values are inherited from virtio_ccw's notify()
callback. We might want to support even more of them lateron.

notify() return values are defined in include/linux/notifier.h.

Signed-off-by: Heinz Graalfs graa...@linux.vnet.ibm.com
---
 drivers/virtio/virtio.c |  8 
 include/linux/virtio.h  | 10 ++
 2 files changed, 18 insertions(+)

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index ee59b74..a09abb4 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -186,6 +186,14 @@ void unregister_virtio_driver(struct virtio_driver *driver)
 }
 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
 
+int notify_virtio_device(struct virtio_device *vdev, int event)
+{
+   struct virtio_driver *drv = drv_to_virtio(vdev-dev.driver);
+
+   return drv-notify ? drv-notify(vdev, event) : NOTIFY_DONE;
+}
+EXPORT_SYMBOL_GPL(notify_virtio_device);
+
 int register_virtio_device(struct virtio_device *dev)
 {
int err;
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index f15f6e7..da18e9a 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -110,6 +110,15 @@ int register_virtio_device(struct virtio_device *dev);
 void unregister_virtio_device(struct virtio_device *dev);
 
 /**
+ * notify event values
+ * @VDEV_GONE: device gone
+ */
+enum {
+   VDEV_GONE   = 1,
+};
+int notify_virtio_device(struct virtio_device *dev, int event);
+
+/**
  * virtio_driver - operations for a virtio I/O driver
  * @driver: underlying device driver (populate name and owner).
  * @id_table: the ids serviced by this driver.
@@ -129,6 +138,7 @@ struct virtio_driver {
void (*scan)(struct virtio_device *dev);
void (*remove)(struct virtio_device *dev);
void (*config_changed)(struct virtio_device *dev);
+   int (*notify)(struct virtio_device *dev, int event);
 #ifdef CONFIG_PM
int (*freeze)(struct virtio_device *dev);
int (*restore)(struct virtio_device *dev);
-- 
1.8.3.1

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Re: [PATCH RFC 1/3] virtio: add notify() callback to virtio_driver

[Rusty Russell]

Heinz Graalfs graa...@linux.vnet.ibm.com writes:
 Add an optional notify() callback to virtio_driver. A backend
 driver can provide this callback to perform actions for a lost
 device.

 notify() event values are inherited from virtio_ccw's notify()
 callback. We might want to support even more of them lateron.

 notify() return values are defined in include/linux/notifier.h.

 Signed-off-by: Heinz Graalfs graa...@linux.vnet.ibm.com

These patches seem sensible.  I've applied them in my pending queue,
but it'd be nice to have some feedback on the virtio_blk.c patch.

Cheers,
Rusty.
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Re: [PATCH RFC 1/3] virtio: add notify() callback to virtio_driver

[Michael S. Tsirkin]

On Wed, Nov 20, 2013 at 04:22:01PM +0100, Heinz Graalfs wrote:
 Add an optional notify() callback to virtio_driver. A backend
 driver can provide this callback to perform actions for a lost
 device.
 
 notify() event values are inherited from virtio_ccw's notify()
 callback. We might want to support even more of them lateron.
 
 notify() return values are defined in include/linux/notifier.h.
 
 Signed-off-by: Heinz Graalfs graa...@linux.vnet.ibm.com
 ---
  drivers/virtio/virtio.c |  8 
  include/linux/virtio.h  | 10 ++
  2 files changed, 18 insertions(+)
 
 diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
 index ee59b74..a09abb4 100644
 --- a/drivers/virtio/virtio.c
 +++ b/drivers/virtio/virtio.c
 @@ -186,6 +186,14 @@ void unregister_virtio_driver(struct virtio_driver 
 *driver)
  }
  EXPORT_SYMBOL_GPL(unregister_virtio_driver);
  
 +int notify_virtio_device(struct virtio_device *vdev, int event)
 +{
 + struct virtio_driver *drv = drv_to_virtio(vdev-dev.driver);
 +
 + return drv-notify ? drv-notify(vdev, event) : NOTIFY_DONE;

Also pls include linux/notifier.h for this value.

 +}
 +EXPORT_SYMBOL_GPL(notify_virtio_device);
 +
  int register_virtio_device(struct virtio_device *dev)
  {
   int err;
 diff --git a/include/linux/virtio.h b/include/linux/virtio.h
 index f15f6e7..da18e9a 100644
 --- a/include/linux/virtio.h
 +++ b/include/linux/virtio.h
 @@ -110,6 +110,15 @@ int register_virtio_device(struct virtio_device *dev);
  void unregister_virtio_device(struct virtio_device *dev);
  
  /**
 + * notify event values
 + * @VDEV_GONE: device gone
 + */
 +enum {
 + VDEV_GONE   = 1,

Seems a bit short, can lead to namespace pollution.
Let's rename to VIRTIO_DEVICE_GONE ?

 +};
 +int notify_virtio_device(struct virtio_device *dev, int event);
 +
 +/**
   * virtio_driver - operations for a virtio I/O driver
   * @driver: underlying device driver (populate name and owner).
   * @id_table: the ids serviced by this driver.
 @@ -129,6 +138,7 @@ struct virtio_driver {
   void (*scan)(struct virtio_device *dev);
   void (*remove)(struct virtio_device *dev);
   void (*config_changed)(struct virtio_device *dev);
 + int (*notify)(struct virtio_device *dev, int event);
  #ifdef CONFIG_PM
   int (*freeze)(struct virtio_device *dev);
   int (*restore)(struct virtio_device *dev);
 -- 
 1.8.3.1
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