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

[Jason Wang <jasowang@redhat.com>]

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);
>