Commit c46eccda authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
Browse files

virtio: document virtio_reset_device 



Looks like most callers get driver/device removal wrong.
Document what's expected of callers.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 4fa59ede

drivers/virtio/virtio.c

+16 −0
Original line number Diff line number Diff line
@@ -202,6 +202,22 @@ static int virtio_features_ok(struct virtio_device *dev) 
	return 0;

}



/**

 * virtio_reset_device - quiesce device for removal

 * @dev: the device to reset

 *

 * Prevents device from sending interrupts and accessing memory.

 *

 * Generally used for cleanup during driver / device removal.

 *

 * Once this has been invoked, caller must ensure that

 * virtqueue_notify / virtqueue_kick are not in progress.

 *

 * Note: this guarantees that vq callbacks are not in progress, however caller

 * is responsible for preventing access from other contexts, such as a system

 * call/workqueue/bh.  Invoking virtio_break_device then flushing any such

 * contexts is one way to handle that.

 * */

void virtio_reset_device(struct virtio_device *dev)

{

	dev->config->reset(dev);