X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=include%2Flinux%2Fvirtio.h;h=06005fa9e982e0f703a7eef56f4108378c566f24;hb=e66d90fb4abd0a27ee96f57a32fb561221c4d6ae;hp=260d1fcf29a4222c011ab39176b1e2e4d46a98a3;hpb=8f859016ea49cd8d7c743533bd1ab3db9a813ffa;p=linux-2.6-omap-h63xx.git

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 260d1fcf29a..06005fa9e98 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -41,13 +41,17 @@ struct virtqueue
  *	Returns NULL or the "data" token handed to add_buf.
  * @disable_cb: disable callbacks
  *	vq: the struct virtqueue we're talking about.
+ *	Note that this is not necessarily synchronous, hence unreliable and only
+ *	useful as an optimization.
  * @enable_cb: restart callbacks after disable_cb.
  *	vq: the struct virtqueue we're talking about.
- *	This returns "false" (and doesn't re-enable) if there are pending
- *	buffers in the queue, to avoid a race.
+ *	This re-enables callbacks; it returns "false" if there are pending
+ *	buffers in the queue, to detect a possible race between the driver
+ *	checking for more work, and enabling callbacks.
  *
  * Locking rules are straightforward: the driver is responsible for
- * locking.  No two operations may be invoked simultaneously.
+ * locking.  No two operations may be invoked simultaneously, with the exception
+ * of @disable_cb.
  *
  * All operations can be called in any context.
  */
@@ -72,6 +76,7 @@ struct virtqueue_ops {
  * @dev: underlying device.
  * @id: the device type identification (used to match it with a driver).
  * @config: the configuration ops for this device.
+ * @features: the features supported by both driver and device.
  * @priv: private pointer for the driver's use.
  */
 struct virtio_device
@@ -80,6 +85,8 @@ struct virtio_device
 	struct device dev;
 	struct virtio_device_id id;
 	struct virtio_config_ops *config;
+	/* Note that this is a Linux set_bit-style bitmap. */
+	unsigned long features[1];
 	void *priv;
 };
 
@@ -90,6 +97,8 @@ void unregister_virtio_device(struct virtio_device *dev);
  * 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.
+ * @feature_table: an array of feature numbers supported by this device.
+ * @feature_table_size: number of entries in the feature table array.
  * @probe: the function to call when a device is found.  Returns a token for
  *    remove, or PTR_ERR().
  * @remove: the function when a device is removed.
@@ -99,6 +108,8 @@ void unregister_virtio_device(struct virtio_device *dev);
 struct virtio_driver {
 	struct device_driver driver;
 	const struct virtio_device_id *id_table;
+	const unsigned int *feature_table;
+	unsigned int feature_table_size;
 	int (*probe)(struct virtio_device *dev);
 	void (*remove)(struct virtio_device *dev);
 	void (*config_changed)(struct virtio_device *dev);