* 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.
*/
* @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
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;
};
* 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.
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);