If support xsk, a new ptr will be recovered during the
process of freeing the old ptr. In order to distinguish between ctx sent
by XDP_TX and ctx sent by xsk, a struct is added here to distinguish
between these two situations. virtnet_xdp_type.type It is used to
distinguish different ctx, and virtnet_xdp_type.offset is used to record
the offset between "true ctx" and virtnet_xdp_type.

The newly added virtnet_xsk_hdr will be used for xsk.

Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 77 ++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 62 insertions(+), 15 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f2349b8..df38a9f 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -94,6 +94,22 @@ struct virtnet_rq_stats {
        u64 kicks;
 };
 
+enum {
+       XDP_TYPE_XSK,
+       XDP_TYPE_TX,
+};
+
+struct virtnet_xdp_type {
+       int offset:24;
+       unsigned type:8;
+};
+
+struct virtnet_xsk_hdr {
+       struct virtnet_xdp_type type;
+       struct virtio_net_hdr_mrg_rxbuf hdr;
+       u32 len;
+};
+
 #define VIRTNET_SQ_STAT(m)     offsetof(struct virtnet_sq_stats, m)
 #define VIRTNET_RQ_STAT(m)     offsetof(struct virtnet_rq_stats, m)
 
@@ -252,14 +268,19 @@ static bool is_xdp_frame(void *ptr)
        return (unsigned long)ptr & VIRTIO_XDP_FLAG;
 }
 
-static void *xdp_to_ptr(struct xdp_frame *ptr)
+static void *xdp_to_ptr(struct virtnet_xdp_type *ptr)
 {
        return (void *)((unsigned long)ptr | VIRTIO_XDP_FLAG);
 }
 
-static struct xdp_frame *ptr_to_xdp(void *ptr)
+static struct virtnet_xdp_type *ptr_to_xtype(void *ptr)
 {
-       return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG);
+       return (struct virtnet_xdp_type *)((unsigned long)ptr & 
~VIRTIO_XDP_FLAG);
+}
+
+static void *xtype_got_ptr(struct virtnet_xdp_type *xdptype)
+{
+       return (char *)xdptype + xdptype->offset;
 }
 
 /* Converting between virtqueue no. and kernel tx/rx queue no.
@@ -460,11 +481,16 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
                                   struct xdp_frame *xdpf)
 {
        struct virtio_net_hdr_mrg_rxbuf *hdr;
+       struct virtnet_xdp_type *xdptype;
        int err;
 
-       if (unlikely(xdpf->headroom < vi->hdr_len))
+       if (unlikely(xdpf->headroom < vi->hdr_len + sizeof(*xdptype)))
                return -EOVERFLOW;
 
+       xdptype = (struct virtnet_xdp_type *)(xdpf + 1);
+       xdptype->offset = (char *)xdpf - (char *)xdptype;
+       xdptype->type = XDP_TYPE_TX;
+
        /* Make room for virtqueue hdr (also change xdpf->headroom?) */
        xdpf->data -= vi->hdr_len;
        /* Zero header and leave csum up to XDP layers */
@@ -474,7 +500,7 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
 
        sg_init_one(sq->sg, xdpf->data, xdpf->len);
 
-       err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdpf),
+       err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdptype),
                                   GFP_ATOMIC);
        if (unlikely(err))
                return -ENOSPC; /* Caller handle free/refcnt */
@@ -544,8 +570,11 @@ static int virtnet_xdp_xmit(struct net_device *dev,
        /* Free up any pending old buffers before queueing new ones. */
        while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
                if (likely(is_xdp_frame(ptr))) {
-                       struct xdp_frame *frame = ptr_to_xdp(ptr);
+                       struct virtnet_xdp_type *xtype;
+                       struct xdp_frame *frame;
 
+                       xtype = ptr_to_xtype(ptr);
+                       frame = xtype_got_ptr(xtype);
                        bytes += frame->len;
                        xdp_return_frame(frame);
                } else {
@@ -1395,24 +1424,34 @@ static int virtnet_receive(struct receive_queue *rq, 
int budget,
 
 static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi)
 {
-       unsigned int len;
        unsigned int packets = 0;
        unsigned int bytes = 0;
-       void *ptr;
+       unsigned int len;
+       struct virtnet_xdp_type *xtype;
+       struct xdp_frame        *frame;
+       struct virtnet_xsk_hdr  *xskhdr;
+       struct sk_buff          *skb;
+       void                    *ptr;
 
        while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
                if (likely(!is_xdp_frame(ptr))) {
-                       struct sk_buff *skb = ptr;
+                       skb = ptr;
 
                        pr_debug("Sent skb %p\n", skb);
 
                        bytes += skb->len;
                        napi_consume_skb(skb, in_napi);
                } else {
-                       struct xdp_frame *frame = ptr_to_xdp(ptr);
+                       xtype = ptr_to_xtype(ptr);
 
-                       bytes += frame->len;
-                       xdp_return_frame(frame);
+                       if (xtype->type == XDP_TYPE_XSK) {
+                               xskhdr = (struct virtnet_xsk_hdr *)xtype;
+                               bytes += xskhdr->len;
+                       } else {
+                               frame = xtype_got_ptr(xtype);
+                               xdp_return_frame(frame);
+                               bytes += frame->len;
+                       }
                }
                packets++;
        }
@@ -2675,14 +2714,22 @@ static void free_unused_bufs(struct virtnet_info *vi)
 {
        void *buf;
        int i;
+       struct send_queue *sq;
 
        for (i = 0; i < vi->max_queue_pairs; i++) {
                struct virtqueue *vq = vi->sq[i].vq;
+               sq = vi->sq + i;
                while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
-                       if (!is_xdp_frame(buf))
+                       if (!is_xdp_frame(buf)) {
                                dev_kfree_skb(buf);
-                       else
-                               xdp_return_frame(ptr_to_xdp(buf));
+                       } else {
+                               struct virtnet_xdp_type *xtype;
+
+                               xtype = ptr_to_xtype(buf);
+
+                               if (xtype->type != XDP_TYPE_XSK)
+                                       xdp_return_frame(xtype_got_ptr(xtype));
+                       }
                }
        }
 
-- 
1.8.3.1

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