[PATCH v12 02/40] virtio: struct virtio_config_ops add callbacks for queue_reset

Xuan Zhuo
2022-07-20T03:04:55Z

reset can be divided into the following four steps (example):
1. transport: notify the device to reset the queue
2. vring: recycle the buffer submitted
3. vring: reset/resize the vring (may re-alloc)
4. transport: mmap vring to device, and enable the queue

In order to support queue reset, add two callbacks in struct
virtio_config_ops to implement steps 1 and 4.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
include/linux/virtio_config.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index b47c2e7ed0ee..36ec7be1f480 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -78,6 +78,18 @@ struct virtio_shm_region {
* @set_vq_affinity: set the affinity for a virtqueue (optional).
* @get_vq_affinity: get the affinity for a virtqueue (optional).
* @get_shm_region: get a shared memory region based on the index.
+ * @disable_vq_and_reset: reset a queue individually (optional).
+ * vq: the virtqueue
+ * Returns 0 on success or error status
+ * disable_vq_and_reset will guarantee that the callbacks are disabled and
+ * synchronized.
+ * Except for the callback, the caller should guarantee that the vring is
+ * not accessed by any functions of virtqueue.
+ * @enable_vq_after_reset: enable a reset queue
+ * vq: the virtqueue
+ * Returns 0 on success or error status
+ * If disable_vq_and_reset is set, then enable_vq_after_reset must also be
+ * set.
*/
typedef void vq_callback_t(struct virtqueue *);
struct virtio_config_ops {
@@ -104,6 +116,8 @@ struct virtio_config_ops {
int index);
bool (*get_shm_region)(struct virtio_device *vdev,
struct virtio_shm_region *region, u8 id);
+ int (*disable_vq_and_reset)(struct virtqueue *vq);
+ int (*enable_vq_after_reset)(struct virtqueue *vq);
};

/* If driver didn't advertise the feature, it will never appear. */
--
2.31.0