Re: [PATCH v11 09/40] virtio_ring: split: extract the logic of alloc state and extra

Jason Wang
2022-07-01T08:55:25Z

在 2022/6/29 14:56, Xuan Zhuo 写道:
> Separate the logic of creating desc_state, desc_extra, and subsequent
> patches will call it independently.
>
> Since only the structure vring is passed into __vring_new_virtqueue(),
> when creating the function vring_alloc_state_extra_split(), we prefer to
> use vring_virtqueue_split as a parameter, and it will be more convenient
> to pass vring_virtqueue_split to some subsequent functions.
>
> So a new vring_virtqueue_split variable is added in
> __vring_new_virtqueue().
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
> drivers/virtio/virtio_ring.c | 58 +++++++++++++++++++++++++-----------
> 1 file changed, 40 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index a9ceb9c16c54..cedd340d6db7 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -204,6 +204,7 @@ struct vring_virtqueue {
> #endif
> };
>
> +static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
>
> /*
> * Helpers.
> @@ -939,6 +940,32 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
> return NULL;
> }
>
> +static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring)
> +{
> + struct vring_desc_state_split *state;
> + struct vring_desc_extra *extra;
> + u32 num = vring->vring.num;
> +
> + state = kmalloc_array(num, sizeof(struct vring_desc_state_split), GFP_KERNEL);
> + if (!state)
> + goto err_state;
> +
> + extra = vring_alloc_desc_extra(num);
> + if (!extra)
> + goto err_extra;
> +
> + memset(state, 0, num * sizeof(struct vring_desc_state_split));
> +
> + vring->desc_state = state;
> + vring->desc_extra = extra;
> + return 0;
> +
> +err_extra:
> + kfree(state);
> +err_state:
> + return -ENOMEM;
> +}
> +
> static void vring_free_split(struct vring_virtqueue_split *vring,
> struct virtio_device *vdev)
> {
> @@ -2224,7 +2251,7 @@ EXPORT_SYMBOL_GPL(vring_interrupt);
>
> /* Only available for split ring */
> struct virtqueue *__vring_new_virtqueue(unsigned int index,
> - struct vring vring,
> + struct vring _vring,
> struct virtio_device *vdev,
> bool weak_barriers,
> bool context,
> @@ -2232,7 +2259,9 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
> void (*callback)(struct virtqueue *),
> const char *name)
> {
> + struct vring_virtqueue_split vring = {};

Nit: to reduce the change-set, let's use vring_split here?

Other looks good.

Thanks

> struct vring_virtqueue *vq;
> + int err;
>
> if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
> return NULL;
> @@ -2261,7 +2290,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
> vq->split.queue_dma_addr = 0;
> vq->split.queue_size_in_bytes = 0;
>
> - vq->split.vring = vring;
> + vq->split.vring = _vring;
> vq->split.avail_flags_shadow = 0;
> vq->split.avail_idx_shadow = 0;
>
> @@ -2273,30 +2302,23 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
> vq->split.avail_flags_shadow);
> }
>
> - vq->split.desc_state = kmalloc_array(vring.num,
> - sizeof(struct vring_desc_state_split), GFP_KERNEL);
> - if (!vq->split.desc_state)
> - goto err_state;
> + vring.vring = _vring;
>
> - vq->split.desc_extra = vring_alloc_desc_extra(vring.num);
> - if (!vq->split.desc_extra)
> - goto err_extra;
> + err = vring_alloc_state_extra_split(&vring);
> + if (err) {
> + kfree(vq);
> + return NULL;
> + }
>
> - memset(vq->split.desc_state, 0, vring.num *
> - sizeof(struct vring_desc_state_split));
> + vq->split.desc_state = vring.desc_state;
> + vq->split.desc_extra = vring.desc_extra;
>
> - virtqueue_init(vq, vq->split.vring.num);
> + virtqueue_init(vq, vring.vring.num);
>
> spin_lock(&vdev->vqs_list_lock);
> list_add_tail(&vq->vq.list, &vdev->vqs);
> spin_unlock(&vdev->vqs_list_lock);
> return &vq->vq;
> -
> -err_extra:
> - kfree(vq->split.desc_state);
> -err_state:
> - kfree(vq);
> - return NULL;
> }
> EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
>