diff mbox series

[v11,14/40] virtio_ring: split: introduce virtqueue_resize_split()

Message ID 20220629065656.54420-15-xuanzhuo@linux.alibaba.com (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series virtio pci support VIRTIO_F_RING_RESET | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Xuan Zhuo June 29, 2022, 6:56 a.m. UTC
virtio ring split supports resize.

Only after the new vring is successfully allocated based on the new num,
we will release the old vring. In any case, an error is returned,
indicating that the vring still points to the old vring.

In the case of an error, re-initialize(virtqueue_reinit_split()) the
virtqueue to ensure that the vring can be used.

In addition, vring_align, may_reduce_num are necessary for reallocating
vring, so they are retained for creating vq.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

Comments

Jason Wang July 1, 2022, 9:09 a.m. UTC | #1
在 2022/6/29 14:56, Xuan Zhuo 写道:
> virtio ring split supports resize.
>
> Only after the new vring is successfully allocated based on the new num,
> we will release the old vring. In any case, an error is returned,
> indicating that the vring still points to the old vring.
>
> In the case of an error, re-initialize(virtqueue_reinit_split()) the
> virtqueue to ensure that the vring can be used.
>
> In addition, vring_align, may_reduce_num are necessary for reallocating
> vring, so they are retained for creating vq.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
>   drivers/virtio/virtio_ring.c | 32 ++++++++++++++++++++++++++++++++
>   1 file changed, 32 insertions(+)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 9c83c5e6d5a9..1aaa1e5f9991 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -212,6 +212,7 @@ struct vring_virtqueue {
>   };
>   
>   static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
> +static void vring_free(struct virtqueue *_vq);
>   
>   /*
>    * Helpers.
> @@ -1114,6 +1115,37 @@ static struct virtqueue *vring_create_virtqueue_split(
>   	return vq;
>   }
>   
> +static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
> +{
> +	struct vring_virtqueue *vq = to_vvq(_vq);
> +	struct vring_virtqueue_split vring = {};
> +	struct virtio_device *vdev = _vq->vdev;
> +	int err;
> +
> +	err = vring_alloc_queue_split(&vring, vdev, num, vq->split.vring_align,
> +				      vq->split.may_reduce_num);
> +	if (err)
> +		goto err;


It's better to have decouple the allocation future more to avoid any 
rewind here in the future.

But the patch should be fine.

So

Acked-by: Jason Wang <jasowang@redhat.com>


> +
> +	err = vring_alloc_state_extra_split(&vring);
> +	if (err) {
> +		vring_free_split(&vring, vdev);
> +		goto err;
> +	}
> +
> +	vring_free(&vq->vq);
> +
> +	virtqueue_init(vq, vring.vring.num);
> +	virtqueue_vring_attach_split(vq, &vring);
> +	virtqueue_vring_init_split(vq);
> +
> +	return 0;
> +
> +err:
> +	virtqueue_reinit_split(vq);
> +	return -ENOMEM;
> +}
> +
>   
>   /*
>    * Packed ring specific functions - *_packed().
diff mbox series

Patch

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 9c83c5e6d5a9..1aaa1e5f9991 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -212,6 +212,7 @@  struct vring_virtqueue {
 };
 
 static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
+static void vring_free(struct virtqueue *_vq);
 
 /*
  * Helpers.
@@ -1114,6 +1115,37 @@  static struct virtqueue *vring_create_virtqueue_split(
 	return vq;
 }
 
+static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	struct vring_virtqueue_split vring = {};
+	struct virtio_device *vdev = _vq->vdev;
+	int err;
+
+	err = vring_alloc_queue_split(&vring, vdev, num, vq->split.vring_align,
+				      vq->split.may_reduce_num);
+	if (err)
+		goto err;
+
+	err = vring_alloc_state_extra_split(&vring);
+	if (err) {
+		vring_free_split(&vring, vdev);
+		goto err;
+	}
+
+	vring_free(&vq->vq);
+
+	virtqueue_init(vq, vring.vring.num);
+	virtqueue_vring_attach_split(vq, &vring);
+	virtqueue_vring_init_split(vq);
+
+	return 0;
+
+err:
+	virtqueue_reinit_split(vq);
+	return -ENOMEM;
+}
+
 
 /*
  * Packed ring specific functions - *_packed().