Re: [PATCH 20/33] virtio_net: xsk: introduce virtnet_rq_bind_xsk_pool()

On Fri, 3 Feb 2023 03:48:33 -0500, "Michael S. Tsirkin" [off-list ref] wrote:

On Thu, Feb 02, 2023 at 07:00:45PM +0800, Xuan Zhuo wrote:

quoted

This function is used to bind or unbind xsk pool to virtnet rq.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio/Makefile     |  2 +-
 drivers/net/virtio/main.c       |  8 ++---
 drivers/net/virtio/virtio_net.h | 16 ++++++++++
 drivers/net/virtio/xsk.c        | 56 +++++++++++++++++++++++++++++++++
 4 files changed, 76 insertions(+), 6 deletions(-)
 create mode 100644 drivers/net/virtio/xsk.c

diff --git a/drivers/net/virtio/Makefile b/drivers/net/virtio/Makefile
index 15ed7c97fd4f..8c2a884d2dba 100644
--- a/drivers/net/virtio/Makefile
+++ b/drivers/net/virtio/Makefile

@@ -5,4 +5,4 @@

 obj-$(CONFIG_VIRTIO_NET) += virtio_net.o

-virtio_net-y := main.o
+virtio_net-y := main.o xsk.o

diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
index 049a3bb9d88d..0ee23468b795 100644
--- a/drivers/net/virtio/main.c
+++ b/drivers/net/virtio/main.c

@@ -110,7 +110,6 @@ struct padded_vnet_hdr {
 	char padding[12];
 };

-static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
 static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);

 static void *xdp_to_ptr(struct xdp_frame *ptr)

@@ -1351,8 +1350,7 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
  * before we're receiving packets, or from refill_work which is
  * careful to disable receiving (using napi_disable).
  */
-static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
-			  gfp_t gfp)
+bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq, gfp_t gfp)
 {
 	int err;
 	bool oom;

@@ -1388,7 +1386,7 @@ static void skb_recv_done(struct virtqueue *rvq)
 	virtqueue_napi_schedule(&rq->napi, rvq);
 }

-static void virtnet_napi_enable(struct virtqueue *vq, struct napi_struct *napi)
+void virtnet_napi_enable(struct virtqueue *vq, struct napi_struct *napi)
 {
 	napi_enable(napi);

@@ -3284,7 +3282,7 @@ static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
 		xdp_return_frame(ptr_to_xdp(buf));
 }

-static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
+void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)

If you are making this an API now you better document
what it does. Same applies to other stuff you are
making non-static.

I agree.

quoted

 {
 	struct virtnet_info *vi = vq->vdev->priv;
 	int i = vq2rxq(vq);

diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
index b46f083a630a..4a7633714802 100644
--- a/drivers/net/virtio/virtio_net.h
+++ b/drivers/net/virtio/virtio_net.h

@@ -168,6 +168,12 @@ struct send_queue {

 	/* Record whether sq is in reset state. */
 	bool reset;
+
+	struct {
+		struct xsk_buff_pool __rcu *pool;
+
+		dma_addr_t hdr_dma_address;
+	} xsk;
 };

 /* Internal representation of a receive virtqueue */

@@ -200,6 +206,13 @@ struct receive_queue {
 	char name[16];

 	struct xdp_rxq_info xdp_rxq;
+
+	struct {
+		struct xsk_buff_pool __rcu *pool;
+
+		/* xdp rxq used by xsk */
+		struct xdp_rxq_info xdp_rxq;
+	} xsk;
 };

 static inline bool is_xdp_raw_buffer_queue(struct virtnet_info *vi, int q)

@@ -274,4 +287,7 @@ int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
 			unsigned int *xdp_xmit,
 			struct virtnet_rq_stats *stats);
 int virtnet_tx_reset(struct virtnet_info *vi, struct send_queue *sq);
+bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq, gfp_t gfp);
+void virtnet_napi_enable(struct virtqueue *vq, struct napi_struct *napi);
+void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
 #endif

diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
new file mode 100644
index 000000000000..e01ff2abea11
--- /dev/null
+++ b/drivers/net/virtio/xsk.c

@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * virtio-net xsk
+ */
+
+#include "virtio_net.h"
+
+static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queue *rq,
+				    struct xsk_buff_pool *pool, struct net_device *dev)

This static function is unused after this patch, so compiler will
complain. Yes it's just a warning but still not nice.

Otherwise, we need merge some patches, which will increase the difficulty of
review.

Is there a better way to deal with? Remove Static?

Thanks.

quoted

+{
+	bool running = netif_running(vi->dev);
+	int err, qindex;
+
+	qindex = rq - vi->rq;
+
+	if (pool) {
+		err = xdp_rxq_info_reg(&rq->xsk.xdp_rxq, dev, qindex, rq->napi.napi_id);
+		if (err < 0)
+			return err;
+
+		err = xdp_rxq_info_reg_mem_model(&rq->xsk.xdp_rxq,
+						 MEM_TYPE_XSK_BUFF_POOL, NULL);
+		if (err < 0) {
+			xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
+			return err;
+		}
+
+		xsk_pool_set_rxq_info(pool, &rq->xsk.xdp_rxq);
+	} else {
+		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
+	}
+
+	if (running)
+		napi_disable(&rq->napi);
+
+	err = virtqueue_reset(rq->vq, virtnet_rq_free_unused_buf);
+	if (err)
+		netdev_err(vi->dev, "reset rx fail: rx queue index: %d err: %d\n", qindex, err);
+
+	if (pool) {
+		if (err)
+			xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
+		else
+			rcu_assign_pointer(rq->xsk.pool, pool);
+	} else {
+		rcu_assign_pointer(rq->xsk.pool, NULL);
+	}
+
+	if (!try_fill_recv(vi, rq, GFP_KERNEL))
+		schedule_delayed_work(&vi->refill, 0);
+
+	if (running)
+		virtnet_napi_enable(rq->vq, &rq->napi);
+
+	return err;
+}
--
2.32.0.3.g01195cf9f

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