Commit 3762ec05 authored by David Wei's avatar David Wei Committed by Jakub Kicinski
Browse files

netdevsim: add NAPI support 



Add NAPI support to netdevim, similar to veth.

* Add a nsim_rq rx queue structure to hold a NAPI instance and a skb
  queue.
* During xmit, store the skb in the peer skb queue and schedule NAPI.
* During napi_poll(), drain the skb queue and pass up the stack.
* Add assoc between rxq and NAPI instance using netif_queue_set_napi().

Signed-off-by: default avatarDavid Wei <dw@davidwei.uk>
Link: https://lore.kernel.org/r/20240507163228.2066817-2-dw@davidwei.uk


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1d0dc857

drivers/net/netdevsim/netdev.c

+198 −11
Original line number Diff line number Diff line
@@ -28,11 +28,33 @@ 


#include "netdevsim.h"



#define NSIM_RING_SIZE		256



static int nsim_napi_rx(struct nsim_rq *rq, struct sk_buff *skb)

{

	if (skb_queue_len(&rq->skb_queue) > NSIM_RING_SIZE) {

		dev_kfree_skb_any(skb);

		return NET_RX_DROP;

	}



	skb_queue_tail(&rq->skb_queue, skb);

	return NET_RX_SUCCESS;

}



static int nsim_forward_skb(struct net_device *dev, struct sk_buff *skb,

			    struct nsim_rq *rq)

{

	return __dev_forward_skb(dev, skb) ?: nsim_napi_rx(rq, skb);

}



static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev)

{

	struct netdevsim *ns = netdev_priv(dev);

	struct net_device *peer_dev;

	unsigned int len = skb->len;

	struct netdevsim *peer_ns;

	struct nsim_rq *rq;

	int rxq;



	rcu_read_lock();

	if (!nsim_ipsec_tx(ns, skb))
@@ -42,10 +64,18 @@ static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (!peer_ns)

		goto out_drop_free;



	peer_dev = peer_ns->netdev;

	rxq = skb_get_queue_mapping(skb);

	if (rxq >= peer_dev->num_rx_queues)

		rxq = rxq % peer_dev->num_rx_queues;

	rq = &peer_ns->rq[rxq];



	skb_tx_timestamp(skb);

	if (unlikely(dev_forward_skb(peer_ns->netdev, skb) == NET_RX_DROP))

	if (unlikely(nsim_forward_skb(peer_dev, skb, rq) == NET_RX_DROP))

		goto out_drop_cnt;



	napi_schedule(&rq->napi);



	rcu_read_unlock();

	u64_stats_update_begin(&ns->syncp);

	ns->tx_packets++;
@@ -300,25 +330,146 @@ static int nsim_get_iflink(const struct net_device *dev) 
	return iflink;

}



static int nsim_rcv(struct nsim_rq *rq, int budget)

{

	struct sk_buff *skb;

	int i;



	for (i = 0; i < budget; i++) {

		if (skb_queue_empty(&rq->skb_queue))

			break;



		skb = skb_dequeue(&rq->skb_queue);

		netif_receive_skb(skb);

	}



	return i;

}



static int nsim_poll(struct napi_struct *napi, int budget)

{

	struct nsim_rq *rq = container_of(napi, struct nsim_rq, napi);

	int done;



	done = nsim_rcv(rq, budget);

	napi_complete(napi);



	return done;

}



static int nsim_create_page_pool(struct nsim_rq *rq)

{

	struct page_pool_params p = {

		.order = 0,

		.pool_size = NSIM_RING_SIZE,

		.nid = NUMA_NO_NODE,

		.dev = &rq->napi.dev->dev,

		.napi = &rq->napi,

		.dma_dir = DMA_BIDIRECTIONAL,

		.netdev = rq->napi.dev,

	};



	rq->page_pool = page_pool_create(&p);

	if (IS_ERR(rq->page_pool)) {

		int err = PTR_ERR(rq->page_pool);



		rq->page_pool = NULL;

		return err;

	}

	return 0;

}



static int nsim_init_napi(struct netdevsim *ns)

{

	struct net_device *dev = ns->netdev;

	struct nsim_rq *rq;

	int err, i;



	for (i = 0; i < dev->num_rx_queues; i++) {

		rq = &ns->rq[i];



		netif_napi_add(dev, &rq->napi, nsim_poll);

	}



	for (i = 0; i < dev->num_rx_queues; i++) {

		rq = &ns->rq[i];



		err = nsim_create_page_pool(rq);

		if (err)

			goto err_pp_destroy;

	}



	return 0;



err_pp_destroy:

	while (i--) {

		page_pool_destroy(ns->rq[i].page_pool);

		ns->rq[i].page_pool = NULL;

	}



	for (i = 0; i < dev->num_rx_queues; i++)

		__netif_napi_del(&ns->rq[i].napi);



	return err;

}



static void nsim_enable_napi(struct netdevsim *ns)

{

	struct net_device *dev = ns->netdev;

	int i;



	for (i = 0; i < dev->num_rx_queues; i++) {

		struct nsim_rq *rq = &ns->rq[i];



		netif_queue_set_napi(dev, i, NETDEV_QUEUE_TYPE_RX, &rq->napi);

		napi_enable(&rq->napi);

	}

}



static int nsim_open(struct net_device *dev)

{

	struct netdevsim *ns = netdev_priv(dev);

	struct page_pool_params pp = { 0 };

	int err;



	pp.pool_size = 128;

	pp.dev = &dev->dev;

	pp.dma_dir = DMA_BIDIRECTIONAL;

	pp.netdev = dev;

	err = nsim_init_napi(ns);

	if (err)

		return err;



	nsim_enable_napi(ns);



	return 0;

}



	ns->pp = page_pool_create(&pp);

	return PTR_ERR_OR_ZERO(ns->pp);

static void nsim_del_napi(struct netdevsim *ns)

{

	struct net_device *dev = ns->netdev;

	int i;



	for (i = 0; i < dev->num_rx_queues; i++) {

		struct nsim_rq *rq = &ns->rq[i];



		napi_disable(&rq->napi);

		__netif_napi_del(&rq->napi);

	}

	synchronize_net();



	for (i = 0; i < dev->num_rx_queues; i++) {

		page_pool_destroy(ns->rq[i].page_pool);

		ns->rq[i].page_pool = NULL;

	}

}



static int nsim_stop(struct net_device *dev)

{

	struct netdevsim *ns = netdev_priv(dev);

	struct netdevsim *peer;



	netif_carrier_off(dev);

	peer = rtnl_dereference(ns->peer);

	if (peer)

		netif_carrier_off(peer->netdev);



	page_pool_destroy(ns->pp);

	nsim_del_napi(ns);



	return 0;

}
@@ -437,7 +588,7 @@ nsim_pp_hold_write(struct file *file, const char __user *data, 
	if (!netif_running(ns->netdev) && val) {

		ret = -ENETDOWN;

	} else if (val) {

		ns->page = page_pool_dev_alloc_pages(ns->pp);

		ns->page = page_pool_dev_alloc_pages(ns->rq[0].page_pool);

		if (!ns->page)

			ret = -ENOMEM;

	} else {
@@ -477,6 +628,35 @@ static void nsim_setup(struct net_device *dev) 
	dev->xdp_features = NETDEV_XDP_ACT_HW_OFFLOAD;

}



static int nsim_queue_init(struct netdevsim *ns)

{

	struct net_device *dev = ns->netdev;

	int i;



	ns->rq = kvcalloc(dev->num_rx_queues, sizeof(*ns->rq),

			  GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL);

	if (!ns->rq)

		return -ENOMEM;



	for (i = 0; i < dev->num_rx_queues; i++)

		skb_queue_head_init(&ns->rq[i].skb_queue);



	return 0;

}



static void nsim_queue_free(struct netdevsim *ns)

{

	struct net_device *dev = ns->netdev;

	int i;



	for (i = 0; i < dev->num_rx_queues; i++)

		skb_queue_purge_reason(&ns->rq[i].skb_queue,

				       SKB_DROP_REASON_QUEUE_PURGE);



	kvfree(ns->rq);

	ns->rq = NULL;

}



static int nsim_init_netdevsim(struct netdevsim *ns)

{

	struct mock_phc *phc;
@@ -495,10 +675,14 @@ static int nsim_init_netdevsim(struct netdevsim *ns) 
		goto err_phc_destroy;



	rtnl_lock();

	err = nsim_bpf_init(ns);

	err = nsim_queue_init(ns);

	if (err)

		goto err_utn_destroy;



	err = nsim_bpf_init(ns);

	if (err)

		goto err_rq_destroy;



	nsim_macsec_init(ns);

	nsim_ipsec_init(ns);
@@ -512,6 +696,8 @@ static int nsim_init_netdevsim(struct netdevsim *ns) 
	nsim_ipsec_teardown(ns);

	nsim_macsec_teardown(ns);

	nsim_bpf_uninit(ns);

err_rq_destroy:

	nsim_queue_free(ns);

err_utn_destroy:

	rtnl_unlock();

	nsim_udp_tunnels_info_destroy(ns->netdev);
@@ -593,6 +779,7 @@ void nsim_destroy(struct netdevsim *ns) 
		nsim_macsec_teardown(ns);

		nsim_ipsec_teardown(ns);

		nsim_bpf_uninit(ns);

		nsim_queue_free(ns);

	}

	rtnl_unlock();

	if (nsim_dev_port_is_pf(ns->nsim_dev_port))

drivers/net/netdevsim/netdevsim.h

+7 −1
Original line number Diff line number Diff line
@@ -90,11 +90,18 @@ struct nsim_ethtool { 
	struct ethtool_fecparam fec;

};



struct nsim_rq {

	struct napi_struct napi;

	struct sk_buff_head skb_queue;

	struct page_pool *page_pool;

};



struct netdevsim {

	struct net_device *netdev;

	struct nsim_dev *nsim_dev;

	struct nsim_dev_port *nsim_dev_port;

	struct mock_phc *phc;

	struct nsim_rq *rq;



	u64 tx_packets;

	u64 tx_bytes;
@@ -125,7 +132,6 @@ struct netdevsim { 
		struct debugfs_u32_array dfs_ports[2];

	} udp_ports;



	struct page_pool *pp;

	struct page *page;

	struct dentry *pp_dfs;