Re: [PATCH RFC v7 04/14] vhost/net: pass net specific struct pointer

[Eugenio Pérez <eperezma@xxxxxxxxxx>]

On Wed, 2020-06-10 at 07:36 -0400, Michael S. Tsirkin wrote:
> In preparation for further cleanup, pass net specific pointer
> to ubuf callbacks so we can move net specific fields
> out to net structures.
> 
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
>  drivers/vhost/net.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index bf5e1d81ae25..ff594eec8ae3 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -94,7 +94,7 @@ struct vhost_net_ubuf_ref {
>  	 */
>  	atomic_t refcount;
>  	wait_queue_head_t wait;
> -	struct vhost_virtqueue *vq;
> +	struct vhost_net_virtqueue *nvq;
>  };
>  
>  #define VHOST_NET_BATCH 64
> @@ -231,7 +231,7 @@ static void vhost_net_enable_zcopy(int vq)
>  }
>  
>  static struct vhost_net_ubuf_ref *
> -vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
> +vhost_net_ubuf_alloc(struct vhost_net_virtqueue *nvq, bool zcopy)
>  {
>  	struct vhost_net_ubuf_ref *ubufs;
>  	/* No zero copy backend? Nothing to count. */
> @@ -242,7 +242,7 @@ vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
>  		return ERR_PTR(-ENOMEM);
>  	atomic_set(&ubufs->refcount, 1);
>  	init_waitqueue_head(&ubufs->wait);
> -	ubufs->vq = vq;
> +	ubufs->nvq = nvq;
>  	return ubufs;
>  }
>  
> @@ -384,13 +384,13 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net,
>  static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
>  {
>  	struct vhost_net_ubuf_ref *ubufs = ubuf->ctx;
> -	struct vhost_virtqueue *vq = ubufs->vq;
> +	struct vhost_net_virtqueue *nvq = ubufs->nvq;
>  	int cnt;
>  
>  	rcu_read_lock_bh();
>  
>  	/* set len to mark this desc buffers done DMA */
> -	vq->heads[ubuf->desc].len = success ?
> +	nvq->vq.heads[ubuf->desc].in_len = success ?

Not like this matter a lot, because it will be override in next patches of the series, but `.len` has been replaced by
`.in_len`, making compiler complain. This fixes it:

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ff594eec8ae3..fdecf39c9ac9 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -390,7 +390,7 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
        rcu_read_lock_bh();
 
        /* set len to mark this desc buffers done DMA */
-       nvq->vq.heads[ubuf->desc].in_len = success ?
+       nvq->vq.heads[ubuf->desc].len = success ?
                VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
        cnt = vhost_net_ubuf_put(ubufs);

>  		VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
>  	cnt = vhost_net_ubuf_put(ubufs);
>  
> @@ -402,7 +402,7 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
>  	 * less than 10% of times).
>  	 */
>  	if (cnt <= 1 || !(cnt % 16))
> -		vhost_poll_queue(&vq->poll);
> +		vhost_poll_queue(&nvq->vq.poll);
>  
>  	rcu_read_unlock_bh();
>  }
> @@ -1525,7 +1525,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
>  	/* start polling new socket */
>  	oldsock = vhost_vq_get_backend(vq);
>  	if (sock != oldsock) {
> -		ubufs = vhost_net_ubuf_alloc(vq,
> +		ubufs = vhost_net_ubuf_alloc(nvq,
>  					     sock && vhost_sock_zcopy(sock));
>  		if (IS_ERR(ubufs)) {
>  			r = PTR_ERR(ubufs);