Commit 6fea20e5 authored by Xuan Zhuo's avatar Xuan Zhuo Committed by Michael S. Tsirkin
Browse files

virtio_ring: split: introduce virtqueue_resize_split() 



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.

Signed-off-by: default avatarXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Message-Id: <20220801063902.129329-17-xuanzhuo@linux.alibaba.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent af36b16f

drivers/virtio/virtio_ring.c

+34 −0
Original line number Diff line number Diff line
@@ -220,6 +220,7 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index, 
					       void (*callback)(struct virtqueue *),

					       const char *name);

static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);

static void vring_free(struct virtqueue *_vq);



/*

 * Helpers.
@@ -1114,6 +1115,39 @@ static struct virtqueue *vring_create_virtqueue_split( 
	return vq;

}



static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)

{

	struct vring_virtqueue_split vring_split = {};

	struct vring_virtqueue *vq = to_vvq(_vq);

	struct virtio_device *vdev = _vq->vdev;

	int err;



	err = vring_alloc_queue_split(&vring_split, vdev, num,

				      vq->split.vring_align,

				      vq->split.may_reduce_num);

	if (err)

		goto err;



	err = vring_alloc_state_extra_split(&vring_split);

	if (err)

		goto err_state_extra;



	vring_free(&vq->vq);



	virtqueue_vring_init_split(&vring_split, vq);



	virtqueue_init(vq, vring_split.vring.num);

	virtqueue_vring_attach_split(vq, &vring_split);



	return 0;



err_state_extra:

	vring_free_split(&vring_split, vdev);

err:

	virtqueue_reinit_split(vq);

	return -ENOMEM;

}





/*

 * Packed ring specific functions - *_packed().