[PATCH net-next v4 14/15] virtio_net: xsk: rx: support fill with xsk buffer

[Xuan Zhuo]

Implement the logic of filling rq with XSK buffers.

Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 64 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 62 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d38b4ef80f6f..a780dcc4dd4f 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -387,6 +387,8 @@ struct receive_queue {
 
                /* xdp rxq used by xsk */
                struct xdp_rxq_info xdp_rxq;
+
+               struct xdp_buff **xsk_buffs;
        } xsk;
 };
 
@@ -531,6 +533,8 @@ struct virtio_net_common_hdr {
 
 static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
 static void virtnet_xsk_completed(struct send_queue *sq, int num);
+static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct 
receive_queue *rq,
+                                  struct xsk_buff_pool *pool, gfp_t gfp);
 
 enum virtnet_xmit_type {
        VIRTNET_XMIT_TYPE_SKB,
@@ -1295,6 +1299,47 @@ static void sg_fill_dma(struct scatterlist *sg, 
dma_addr_t addr, u32 len)
        sg->length = len;
 }
 
+static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct 
receive_queue *rq,
+                                  struct xsk_buff_pool *pool, gfp_t gfp)
+{
+       struct xdp_buff **xsk_buffs;
+       dma_addr_t addr;
+       u32 len, i;
+       int err = 0;
+       int num;
+
+       xsk_buffs = rq->xsk.xsk_buffs;
+
+       num = xsk_buff_alloc_batch(pool, xsk_buffs, rq->vq->num_free);
+       if (!num)
+               return -ENOMEM;
+
+       len = xsk_pool_get_rx_frame_size(pool) + vi->hdr_len;
+
+       for (i = 0; i < num; ++i) {
+               /* use the part of XDP_PACKET_HEADROOM as the virtnet hdr space 
*/
+               addr = xsk_buff_xdp_get_dma(xsk_buffs[i]) - 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)
+                       goto err;
+       }
+
+       return num;
+
+err:
+       if (i)
+               err = i;
+
+       for (; i < num; ++i)
+               xsk_buff_free(xsk_buffs[i]);
+
+       return err;
+}
+
 static int virtnet_xsk_xmit_one(struct send_queue *sq,
                                struct xsk_buff_pool *pool,
                                struct xdp_desc *desc)
@@ -2551,6 +2596,11 @@ static bool try_fill_recv(struct virtnet_info *vi, 
struct receive_queue *rq,
        int err;
        bool oom;
 
+       if (rq->xsk.pool) {
+               err = virtnet_add_recvbuf_xsk(vi, rq, rq->xsk.pool, gfp);
+               goto kick;
+       }
+
        do {
                if (vi->mergeable_rx_bufs)
                        err = add_recvbuf_mergeable(vi, rq, gfp);
@@ -2559,10 +2609,11 @@ static bool try_fill_recv(struct virtnet_info *vi, 
struct receive_queue *rq,
                else
                        err = add_recvbuf_small(vi, rq, gfp);
 
-               oom = err == -ENOMEM;
                if (err)
                        break;
        } while (rq->vq->num_free);
+
+kick:
        if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {
                unsigned long flags;
 
@@ -2571,6 +2622,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct 
receive_queue *rq,
                u64_stats_update_end_irqrestore(&rq->stats.syncp, flags);
        }
 
+       oom = err == -ENOMEM;
        return !oom;
 }
 
@@ -5440,7 +5492,7 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
        struct send_queue *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.
@@ -5475,6 +5527,12 @@ 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;
+
        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;
@@ -5533,6 +5591,8 @@ 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;
 }
 
-- 
2.32.0.3.g01195cf9f