[PATCH v9 06/32] virtio_ring: split: extract the logic of alloc queue

[Jason Wang]

在 2022/4/6 上午11:43, Xuan Zhuo 写道:
> Separate the logic of split to create vring queue.
>
> This feature is required for subsequent virtuqueue reset vring.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
> ---
>   drivers/virtio/virtio_ring.c | 53 ++++++++++++++++++++++++------------
>   1 file changed, 36 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 33fddfb907a6..72d5ae063fa0 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -915,23 +915,15 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
>   	return NULL;
>   }
>   
> -static struct virtqueue *vring_create_virtqueue_split(
> -	unsigned int index,
> -	unsigned int num,
> -	unsigned int vring_align,
> -	struct virtio_device *vdev,
> -	bool weak_barriers,
> -	bool may_reduce_num,
> -	bool context,
> -	bool (*notify)(struct virtqueue *),
> -	void (*callback)(struct virtqueue *),
> -	const char *name)
> +static void *vring_alloc_queue_split(struct virtio_device *vdev,
> +				     dma_addr_t *dma_addr,
> +				     u32 *n,
> +				     unsigned int vring_align,
> +				     bool weak_barriers,


This is not used in this function.

Thanks


> +				     bool may_reduce_num)
>   {
> -	struct virtqueue *vq;
>   	void *queue = NULL;
> -	dma_addr_t dma_addr;
> -	size_t queue_size_in_bytes;
> -	struct vring vring;
> +	u32 num = *n;
>   
>   	/* We assume num is a power of 2. */
>   	if (num & (num - 1)) {
> @@ -942,7 +934,7 @@ static struct virtqueue *vring_create_virtqueue_split(
>   	/* TODO: allocate each queue chunk individually */
>   	for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
>   		queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
> -					  &dma_addr,
> +					  dma_addr,
>   					  GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
>   		if (queue)
>   			break;
> @@ -956,11 +948,38 @@ static struct virtqueue *vring_create_virtqueue_split(
>   	if (!queue) {
>   		/* Try to get a single page. You are my only hope! */
>   		queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
> -					  &dma_addr, GFP_KERNEL|__GFP_ZERO);
> +					  dma_addr, GFP_KERNEL|__GFP_ZERO);
>   	}
>   	if (!queue)
>   		return NULL;
>   
> +	*n = num;
> +	return queue;
> +}
> +
> +static struct virtqueue *vring_create_virtqueue_split(
> +	unsigned int index,
> +	unsigned int num,
> +	unsigned int vring_align,
> +	struct virtio_device *vdev,
> +	bool weak_barriers,
> +	bool may_reduce_num,
> +	bool context,
> +	bool (*notify)(struct virtqueue *),
> +	void (*callback)(struct virtqueue *),
> +	const char *name)
> +{
> +	size_t queue_size_in_bytes;
> +	struct virtqueue *vq;
> +	dma_addr_t dma_addr;
> +	struct vring vring;
> +	void *queue;
> +
> +	queue = vring_alloc_queue_split(vdev, &dma_addr, &num, vring_align,
> +					weak_barriers, may_reduce_num);
> +	if (!queue)
> +		return NULL;
> +
>   	queue_size_in_bytes = vring_size(num, vring_align);
>   	vring_init(&vring, num, queue, vring_align);
>