virtio: Add ability to detach unused buffers from vrings

There's currently no way for a virtio driver to ask for unused
buffers, so it has to keep a list itself to reclaim them at shutdown.
This is redundant, since virtio_ring stores that information.  So
add a new hook to do this.

Signed-off-by: Shirley Ma <xma@us.ibm.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Shirley Ma 2010-01-18 19:15:23 +05:30 committed by Rusty Russell
parent 69740c8ba8
commit c021eac414
2 changed files with 29 additions and 0 deletions

View file

@ -51,6 +51,9 @@ struct virtqueue {
* 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.
* @detach_unused_buf: detach first unused buffer
* vq: the struct virtqueue we're talking about.
* Returns NULL or the "data" token handed to add_buf
*
* Locking rules are straightforward: the driver is responsible for
* locking. No two operations may be invoked simultaneously, with the exception
@ -71,6 +74,7 @@ struct virtqueue_ops {
void (*disable_cb)(struct virtqueue *vq);
bool (*enable_cb)(struct virtqueue *vq);
void *(*detach_unused_buf)(struct virtqueue *vq);
};
/**