/**
* virtqueue - a queue to register buffers for sending or receiving.
+ * @list: the chain of virtqueues for this device
* @callback: the function to call when buffers are consumed (can be NULL).
- * If this returns false, callbacks are suppressed until vq_ops->restart
- * is called.
+ * @name: the name of this virtqueue (mainly for debugging)
* @vdev: the virtio device this queue was created for.
* @vq_ops: the operations for this virtqueue (see below).
* @priv: a pointer for the virtqueue implementation to use.
*/
-struct virtqueue
-{
- bool (*callback)(struct virtqueue *vq);
+struct virtqueue {
+ struct list_head list;
+ void (*callback)(struct virtqueue *vq);
+ const char *name;
struct virtio_device *vdev;
struct virtqueue_ops *vq_ops;
void *priv;
* out_num: the number of sg readable by other side
* in_num: the number of sg which are writable (after readable ones)
* data: the token identifying the buffer.
- * Returns 0 or an error.
+ * Returns remaining capacity of queue (sg segments) or a negative error.
* @kick: update after add_buf
* vq: the struct virtqueue
* After one or more add_buf calls, invoke this to kick the other side.
* vq: the struct virtqueue we're talking about.
* len: the length written into the buffer
* Returns NULL or the "data" token handed to add_buf.
- * @restart: restart callbacks after callback returned false.
+ * @disable_cb: disable callbacks
* 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.
- * @shutdown: "unadd" all buffers.
+ * 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.
- * Remove everything from the queue.
+ * 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.
*/
void *(*get_buf)(struct virtqueue *vq, unsigned int *len);
- bool (*restart)(struct virtqueue *vq);
-
- void (*shutdown)(struct virtqueue *vq);
+ void (*disable_cb)(struct virtqueue *vq);
+ bool (*enable_cb)(struct virtqueue *vq);
};
/**
* @dev: underlying device.
* @id: the device type identification (used to match it with a driver).
* @config: the configuration ops for this device.
+ * @vqs: the list of virtqueues for this device.
+ * @features: the features supported by both driver and device.
* @priv: private pointer for the driver's use.
*/
-struct virtio_device
-{
+struct virtio_device {
int index;
struct device dev;
struct virtio_device_id id;
struct virtio_config_ops *config;
+ struct list_head vqs;
+ /* 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.
- * @probe: the function to call when a device is found. Returns a token for
- * remove, or PTR_ERR().
+ * @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 0 or -errno.
* @remove: the function when a device is removed.
+ * @config_changed: optional function to call when the device configuration
+ * changes; may be called in interrupt context.
*/
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);
};
int register_virtio_driver(struct virtio_driver *drv);