On Mon, Feb 14, 2022 at 4:14 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> The purpose of this patch is to make vring packed support re-enable reset
> vq.
>
> Based on whether the incoming vq passed by vring_setup_virtqueue() is
> NULL or not, distinguish whether it is a normal create virtqueue or
> re-enable a reset queue.
>
> When re-enable a reset queue, reuse the original callback, name, indirect.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_ring.c | 29 ++++++++++++++++++-----------
> 1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 4639e1643c78..20659f7ca582 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -1683,7 +1683,8 @@ static struct virtqueue *vring_create_virtqueue_packed(
> bool context,
> bool (*notify)(struct virtqueue *),
> void (*callback)(struct virtqueue *),
> - const char *name)
> + const char *name,
> + struct virtqueue *_vq)
> {
> struct vring_virtqueue *vq;
> struct vring_packed_desc *ring;
> @@ -1713,13 +1714,20 @@ static struct virtqueue *vring_create_virtqueue_packed(
> if (!device)
> goto err_device;
>
> - vq = kmalloc(sizeof(*vq), GFP_KERNEL);
> - if (!vq)
> - goto err_vq;
> + if (_vq) {
> + vq = to_vvq(_vq);
> + } else {
> + vq = kmalloc(sizeof(*vq), GFP_KERNEL);
> + if (!vq)
> + goto err_vq;
> +
> + vq->vq.callback = callback;
> + vq->vq.name = name;
> + vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
> + !context;
> + }
The code looks tricky. Except for the memory we don't even need to
touch any of the other attributes.
I'd suggest splitting out the vring allocation into a dedicated helper
that could be called by both vring_create_queue_XXX and the enable()
logic (and in the enable logic we don't even need to relocate if size
is not changed).
Thanks
>
> - vq->vq.callback = callback;
> vq->vq.vdev = vdev;
> - vq->vq.name = name;
> vq->vq.num_free = num;
> vq->vq.index = index;
> vq->we_own_ring = true;
> @@ -1736,8 +1744,6 @@ static struct virtqueue *vring_create_virtqueue_packed(
> vq->last_add_time_valid = false;
> #endif
>
> - vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
> - !context;
> vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
>
> if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
> @@ -1778,7 +1784,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
> goto err_desc_extra;
>
> /* No callback? Tell other side not to bother us. */
> - if (!callback) {
> + if (!vq->vq.callback) {
> vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
> vq->packed.vring.driver->flags =
> cpu_to_le16(vq->packed.event_flags_shadow);
> @@ -1792,7 +1798,8 @@ static struct virtqueue *vring_create_virtqueue_packed(
> err_desc_extra:
> kfree(vq->packed.desc_state);
> err_desc_state:
> - kfree(vq);
> + if (!_vq)
> + kfree(vq);
> err_vq:
> vring_free_queue(vdev, event_size_in_bytes, device, device_event_dma_addr);
> err_device:
> @@ -2317,7 +2324,7 @@ struct virtqueue *vring_setup_virtqueue(
> if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
> return vring_create_virtqueue_packed(index, num, vring_align,
> vdev, weak_barriers, may_reduce_num,
> - context, notify, callback, name);
> + context, notify, callback, name, vq);
>
> return vring_create_virtqueue_split(index, num, vring_align,
> vdev, weak_barriers, may_reduce_num,
> --
> 2.31.0
>
