Re: [PATCH v9 07/32] virtio_ring: split: extract the logic of alloc state and extra

[Jason Wang <jasowang@xxxxxxxxxx>]

在 2022/4/6 上午11:43, Xuan Zhuo 写道:
> Separate the logic of creating desc_state, desc_extra, and subsequent
> patches will call it independently.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
>   drivers/virtio/virtio_ring.c | 53 ++++++++++++++++++++++++++----------
>   1 file changed, 38 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 72d5ae063fa0..6de67439cb57 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -198,6 +198,7 @@ struct vring_virtqueue {
>   #endif
>   };
>   
> +static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
>   
>   /*
>    * Helpers.
> @@ -915,6 +916,33 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
>   	return NULL;
>   }
>   
> +static int vring_alloc_state_extra_split(u32 num,
> +					 struct vring_desc_state_split **desc_state,
> +					 struct vring_desc_extra **desc_extra)
> +{
> +	struct vring_desc_state_split *state;
> +	struct vring_desc_extra *extra;
> +
> +	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));
> +
> +	*desc_state = state;
> +	*desc_extra = extra;
> +	return 0;
> +
> +err_extra:
> +	kfree(state);
> +err_state:
> +	return -ENOMEM;
> +}
> +
>   static void *vring_alloc_queue_split(struct virtio_device *vdev,
>   				     dma_addr_t *dma_addr,
>   				     u32 *n,
> @@ -2196,7 +2224,10 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
>   					void (*callback)(struct virtqueue *),
>   					const char *name)
>   {
> +	struct vring_desc_state_split *state;
> +	struct vring_desc_extra *extra;
>   	struct vring_virtqueue *vq;
> +	int err;
>   
>   	if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
>   		return NULL;
> @@ -2246,30 +2277,22 @@ 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;
> +	err = vring_alloc_state_extra_split(vring.num, &state, &extra);


Nit: we can pass e.g &vq->split.desc_state here to avoid extra temp 
variable and assignment.

Other looks good.

Thanks


> +	if (err) {
> +		kfree(vq);
> +		return NULL;
> +	}
>   
> -	vq->split.desc_extra = vring_alloc_desc_extra(vring.num);
> -	if (!vq->split.desc_extra)
> -		goto err_extra;
> +	vq->split.desc_state = state;
> +	vq->split.desc_extra = extra;
>   
>   	/* Put everything in free lists. */
>   	vq->free_head = 0;
> -	memset(vq->split.desc_state, 0, vring.num *
> -			sizeof(struct vring_desc_state_split));
>   
>   	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);
>