在 2022/2/9 下午8:28, Xuan Zhuo 写道:
Performing reset on a queue is divided into four steps:
1. reset_vq: reset one vq
2. recycle the buffer from vq by virtqueue_detach_unused_buf()
3. release the ring of the vq by vring_release_virtqueue()
4. enable_reset_vq: re-enable the reset queue
So add two callbacks reset_vq, enable_reset_vq to struct
virtio_config_ops.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
include/linux/virtio_config.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 4d107ad31149..0d01a64f2576 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -74,6 +74,17 @@ 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.
+ * @reset_vq: reset a queue individually
This needs to be marked as optional I think.
+ * vq: the virtqueue
+ * Returns 0 on success or error status
It looks to me the caller should also guarantee that the vring is not
accsed by any functions e.g NAPI.
+ * After successfully calling this, be sure to call
+ * virtqueue_detach_unused_buf() to recycle the buffer in the ring, and
+ * then call vring_release_virtqueue() to release the vq ring.
+ * @enable_reset_vq: enable a reset queue
+ * vq: the virtqueue
+ * ring_num: specify ring num for the vq to be re-enabled. 0 means use the
+ * default value. MUST be a power of 2.
Note that we don't have power of 2 requirement for packed virtqueue.
And I wonder if it's cleaner to have a find_vq() ops instead to dealing
with the re-allocation and possible size change, or have a dedicated
helper to set vring size so driver can do.
reset_vq()
virtqueue_set_vring_size()
enable_reset_vq()
+ * Returns 0 on success or error status
*/
typedef void vq_callback_t(struct virtqueue *);
struct virtio_config_ops {
@@ -100,6 +111,8 @@ struct virtio_config_ops {
int index);
bool (*get_shm_region)(struct virtio_device *vdev,
struct virtio_shm_region *region, u8 id);
+ int (*reset_vq)(struct virtqueue *vq);
+ int (*enable_reset_vq)(struct virtqueue *vq, u16 ring_num);
Note that the current implement is best-effort, so it's not guarantee
that we can have a vring with ring_num, we may get less under memory
pressure or even fail. We probably need to have a pamater to mandate the
ring_num otherwise user may surprise to see a decreased size of the ring
when a increasing is actually requested.
Thanks
};
/* If driver didn't advertise the feature, it will never appear. */
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