Re: [PATCH net-next v2 14/21] virtio_net: xsk: tx: virtnet_free_old_xmit() distinguishes xsk buffer

Michael S. Tsirkin
2023-11-09T11:11:58Z

On Tue, Nov 07, 2023 at 11:12:20AM +0800, Xuan Zhuo wrote:
> virtnet_free_old_xmit distinguishes three type ptr(skb, xdp frame, xsk
> buffer) by the last bits of the pointer.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
> drivers/net/virtio/virtio_net.h | 18 ++++++++++++++++--
> drivers/net/virtio/xsk.h | 5 +++++
> 2 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> index a431a2c1ee47..a13d6d301fdb 100644
> --- a/drivers/net/virtio/virtio_net.h
> +++ b/drivers/net/virtio/virtio_net.h
> @@ -225,6 +225,11 @@ struct virtnet_info {
> struct failover *failover;
> };
>
> +static inline bool virtnet_is_skb_ptr(void *ptr)
> +{
> + return !((unsigned long)ptr & VIRTIO_XMIT_DATA_MASK);
> +}
> +
> static inline bool virtnet_is_xdp_frame(void *ptr)
> {
> return (unsigned long)ptr & VIRTIO_XDP_FLAG;
> @@ -235,6 +240,8 @@ static inline struct xdp_frame *virtnet_ptr_to_xdp(void *ptr)
> return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG);
> }
>
> +static inline u32 virtnet_ptr_to_xsk(void *ptr);
> +

I don't understand why you need this here.

> static inline void *virtnet_sq_unmap(struct virtnet_sq *sq, void *data)
> {
> struct virtnet_sq_dma *next, *head;
> @@ -261,11 +268,12 @@ static inline void *virtnet_sq_unmap(struct virtnet_sq *sq, void *data)
> static inline void virtnet_free_old_xmit(struct virtnet_sq *sq, bool in_napi,
> u64 *bytes, u64 *packets)
> {
> + unsigned int xsknum = 0;
> unsigned int len;
> void *ptr;
>
> while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
> - if (!virtnet_is_xdp_frame(ptr)) {
> + if (virtnet_is_skb_ptr(ptr)) {
> struct sk_buff *skb;
>
> if (sq->do_dma)
> @@ -277,7 +285,7 @@ static inline void virtnet_free_old_xmit(struct virtnet_sq *sq, bool in_napi,
>
> *bytes += skb->len;
> napi_consume_skb(skb, in_napi);
> - } else {
> + } else if (virtnet_is_xdp_frame(ptr)) {
> struct xdp_frame *frame;
>
> if (sq->do_dma)
> @@ -287,9 +295,15 @@ static inline void virtnet_free_old_xmit(struct virtnet_sq *sq, bool in_napi,
>
> *bytes += xdp_get_frame_len(frame);
> xdp_return_frame(frame);
> + } else {
> + *bytes += virtnet_ptr_to_xsk(ptr);
> + ++xsknum;
> }
> (*packets)++;
> }
> +
> + if (xsknum)
> + xsk_tx_completed(sq->xsk.pool, xsknum);
> }
>
> static inline bool virtnet_is_xdp_raw_buffer_queue(struct virtnet_info *vi, int q)
> diff --git a/drivers/net/virtio/xsk.h b/drivers/net/virtio/xsk.h
> index 1bd19dcda649..7ebc9bda7aee 100644
> --- a/drivers/net/virtio/xsk.h
> +++ b/drivers/net/virtio/xsk.h
> @@ -14,6 +14,11 @@ static inline void *virtnet_xsk_to_ptr(u32 len)
> return (void *)(p | VIRTIO_XSK_FLAG);
> }
>
> +static inline u32 virtnet_ptr_to_xsk(void *ptr)
> +{
> + return ((unsigned long)ptr) >> VIRTIO_XSK_FLAG_OFFSET;
> +}
> +
> int virtnet_xsk_pool_setup(struct net_device *dev, struct netdev_bpf *xdp);
> bool virtnet_xsk_xmit(struct virtnet_sq *sq, struct xsk_buff_pool *pool,
> int budget);
> --
> 2.32.0.3.g01195cf9f