[PATCH net-next v2 16/21] virtio_net: xsk: rx: introduce add_recvbuf_xsk()

[Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>]

Implement the logic of filling rq with XSK buffers.

Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
 drivers/net/virtio/main.c       |  4 ++-
 drivers/net/virtio/virtio_net.h |  5 ++++
 drivers/net/virtio/xsk.c        | 49 ++++++++++++++++++++++++++++++++-
 drivers/net/virtio/xsk.h        |  2 ++
 4 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
index 6210a6e37396..15943a22e17d 100644
--- a/drivers/net/virtio/main.c
+++ b/drivers/net/virtio/main.c
@@ -1798,7 +1798,9 @@ static bool try_fill_recv(struct virtnet_info *vi, struct virtnet_rq *rq,
 	bool oom;
 
 	do {
-		if (vi->mergeable_rx_bufs)
+		if (rq->xsk.pool)
+			err = virtnet_add_recvbuf_xsk(vi, rq, rq->xsk.pool, gfp);
+		else if (vi->mergeable_rx_bufs)
 			err = add_recvbuf_mergeable(vi, rq, gfp);
 		else if (vi->big_packets)
 			err = add_recvbuf_big(vi, rq, gfp);
diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
index a13d6d301fdb..1242785e311e 100644
--- a/drivers/net/virtio/virtio_net.h
+++ b/drivers/net/virtio/virtio_net.h
@@ -140,6 +140,11 @@ struct virtnet_rq {
 
 		/* xdp rxq used by xsk */
 		struct xdp_rxq_info xdp_rxq;
+
+		struct xdp_buff **xsk_buffs;
+		u32 nxt_idx;
+		u32 num;
+		u32 size;
 	} xsk;
 };
 
diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
index ea5804ddd44e..e737c3353212 100644
--- a/drivers/net/virtio/xsk.c
+++ b/drivers/net/virtio/xsk.c
@@ -38,6 +38,41 @@ static void virtnet_xsk_check_queue(struct virtnet_sq *sq)
 		netif_stop_subqueue(dev, qnum);
 }
 
+int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct virtnet_rq *rq,
+			    struct xsk_buff_pool *pool, gfp_t gfp)
+{
+	struct xdp_buff **xsk_buffs;
+	dma_addr_t addr;
+	u32 len, i;
+	int err = 0;
+
+	xsk_buffs = rq->xsk.xsk_buffs;
+
+	if (rq->xsk.nxt_idx >= rq->xsk.num) {
+		rq->xsk.num = xsk_buff_alloc_batch(pool, xsk_buffs, rq->xsk.size);
+		if (!rq->xsk.num)
+			return -ENOMEM;
+		rq->xsk.nxt_idx = 0;
+	}
+
+	i = rq->xsk.nxt_idx;
+
+	/* use the part of XDP_PACKET_HEADROOM as the virtnet hdr space */
+	addr = xsk_buff_xdp_get_dma(xsk_buffs[i]) - vi->hdr_len;
+	len = xsk_pool_get_rx_frame_size(pool) + vi->hdr_len;
+
+	sg_init_table(rq->sg, 1);
+	sg_fill_dma(rq->sg, addr, len);
+
+	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, xsk_buffs[i], gfp);
+	if (err)
+		return err;
+
+	rq->xsk.nxt_idx++;
+
+	return 0;
+}
+
 static int virtnet_xsk_xmit_one(struct virtnet_sq *sq,
 				struct xsk_buff_pool *pool,
 				struct xdp_desc *desc)
@@ -213,7 +248,7 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
 	struct virtnet_sq *sq;
 	struct device *dma_dev;
 	dma_addr_t hdr_dma;
-	int err;
+	int err, size;
 
 	/* In big_packets mode, xdp cannot work, so there is no need to
 	 * initialize xsk of rq.
@@ -249,6 +284,16 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
 	if (!dma_dev)
 		return -EPERM;
 
+	size = virtqueue_get_vring_size(rq->vq);
+
+	rq->xsk.xsk_buffs = kcalloc(size, sizeof(*rq->xsk.xsk_buffs), GFP_KERNEL);
+	if (!rq->xsk.xsk_buffs)
+		return -ENOMEM;
+
+	rq->xsk.size = size;
+	rq->xsk.nxt_idx = 0;
+	rq->xsk.num = 0;
+
 	hdr_dma = dma_map_single(dma_dev, &xsk_hdr, vi->hdr_len, DMA_TO_DEVICE);
 	if (dma_mapping_error(dma_dev, hdr_dma))
 		return -ENOMEM;
@@ -307,6 +352,8 @@ static int virtnet_xsk_pool_disable(struct net_device *dev, u16 qid)
 
 	dma_unmap_single(dma_dev, sq->xsk.hdr_dma_address, vi->hdr_len, DMA_TO_DEVICE);
 
+	kfree(rq->xsk.xsk_buffs);
+
 	return err1 | err2;
 }
 
diff --git a/drivers/net/virtio/xsk.h b/drivers/net/virtio/xsk.h
index 7ebc9bda7aee..bef41a3f954e 100644
--- a/drivers/net/virtio/xsk.h
+++ b/drivers/net/virtio/xsk.h
@@ -23,4 +23,6 @@ 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);
 int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag);
+int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct virtnet_rq *rq,
+			    struct xsk_buff_pool *pool, gfp_t gfp);
 #endif
-- 
2.32.0.3.g01195cf9f

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