On Mon, Feb 14, 2022 at 4:14 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> Added vring_release_virtqueue() to release the ring of the vq.
>
> In this process, vq is removed from the vdev->vqs queue. And the memory
> of the ring is released
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_ring.c | 18 +++++++++++++++++-
> include/linux/virtio.h | 12 ++++++++++++
> 2 files changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index c5dd17c7dd4a..b37753bdbbc4 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -1730,6 +1730,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
> vq->vq.vdev = vdev;
> vq->vq.num_free = num;
> vq->vq.index = index;
> + vq->vq.reset = VIRTQUEUE_RESET_STAGE_NONE;
So we don't have a similar check for detach_unused_buf(), I guess it
should be sufficient to document the API requirement. Otherwise we
probably need some barriers/ordering which are not worthwhile just for
figuring out bad API usage.
> vq->we_own_ring = true;
> vq->notify = notify;
> vq->weak_barriers = weak_barriers;
> @@ -2218,6 +2219,7 @@ static int __vring_init_virtqueue(struct virtqueue *_vq,
> vq->vq.vdev = vdev;
> vq->vq.num_free = vring.num;
> vq->vq.index = index;
> + vq->vq.reset = VIRTQUEUE_RESET_STAGE_NONE;
> vq->we_own_ring = false;
> vq->notify = notify;
> vq->weak_barriers = weak_barriers;
> @@ -2397,11 +2399,25 @@ void vring_del_virtqueue(struct virtqueue *_vq)
> {
> struct vring_virtqueue *vq = to_vvq(_vq);
>
> - __vring_del_virtqueue(vq);
> + if (_vq->reset != VIRTQUEUE_RESET_STAGE_RELEASE)
> + __vring_del_virtqueue(vq);
> kfree(vq);
> }
> EXPORT_SYMBOL_GPL(vring_del_virtqueue);
>
> +void vring_release_virtqueue(struct virtqueue *_vq)
> +{
If we agree on that we need a allocation routine, we probably need to
rename this as vring_free_virtqueue()
Thanks
> + struct vring_virtqueue *vq = to_vvq(_vq);
> +
> + if (_vq->reset != VIRTQUEUE_RESET_STAGE_DEVICE)
> + return;
> +
> + __vring_del_virtqueue(vq);
> +
> + _vq->reset = VIRTQUEUE_RESET_STAGE_RELEASE;
> +}
> +EXPORT_SYMBOL_GPL(vring_release_virtqueue);
> +
> /* Manipulates transport-specific feature bits. */
> void vring_transport_features(struct virtio_device *vdev)
> {
> diff --git a/include/linux/virtio.h b/include/linux/virtio.h
> index 72292a62cd90..cdb2a551257c 100644
> --- a/include/linux/virtio.h
> +++ b/include/linux/virtio.h
> @@ -10,6 +10,12 @@
> #include <linux/mod_devicetable.h>
> #include <linux/gfp.h>
>
> +enum virtqueue_reset_stage {
> + VIRTQUEUE_RESET_STAGE_NONE,
> + VIRTQUEUE_RESET_STAGE_DEVICE,
> + VIRTQUEUE_RESET_STAGE_RELEASE,
> +};
> +
> /**
> * virtqueue - a queue to register buffers for sending or receiving.
> * @list: the chain of virtqueues for this device
> @@ -32,6 +38,7 @@ struct virtqueue {
> unsigned int index;
> unsigned int num_free;
> void *priv;
> + enum virtqueue_reset_stage reset;
> };
>
> int virtqueue_add_outbuf(struct virtqueue *vq,
> @@ -196,4 +203,9 @@ void unregister_virtio_driver(struct virtio_driver *drv);
> #define module_virtio_driver(__virtio_driver) \
> module_driver(__virtio_driver, register_virtio_driver, \
> unregister_virtio_driver)
> +/*
> + * Resets a virtqueue. Just frees the ring, not free vq.
> + * This function must be called after reset_vq().
> + */
> +void vring_release_virtqueue(struct virtqueue *vq);
> #endif /* _LINUX_VIRTIO_H */
> --
> 2.31.0
>
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