Date: Mon, 21 Aug 2023 16:25:36 -0700
From: Amritha Nambiar <amritha.nambiar@...el.com>
To: netdev@...r.kernel.org, kuba@...nel.org, davem@...emloft.net
Cc: sridhar.samudrala@...el.com, amritha.nambiar@...el.com
Subject: [net-next PATCH v2 5/9] netdev-genl: Add netlink framework
 functions for napi

Implement the netdev netlink framework functions for
napi support. The netdev structure tracks all the napi
instances and napi fields. The napi instances and associated
queue[s] can be retrieved this way.

Signed-off-by: Amritha Nambiar <amritha.nambiar@...el.com>
---
 net/core/netdev-genl.c |  165 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 162 insertions(+), 3 deletions(-)

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index b146679d6112..4bc6aa756001 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -5,9 +5,23 @@
 #include <linux/rtnetlink.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
+#include <net/netdev_rx_queue.h>
 
 #include "netdev-genl-gen.h"
 
+struct netdev_nl_dump_ctx {
+	unsigned long	ifindex;
+	int		napi_idx;
+};
+
+static inline struct netdev_nl_dump_ctx *
+netdev_dump_ctx(struct netlink_callback *cb)
+{
+	NL_ASSERT_DUMP_CTX_FITS(struct netdev_nl_dump_ctx);
+
+	return (struct netdev_nl_dump_ctx *)cb->ctx;
+}
+
 static int
 netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
 		   const struct genl_info *info)
@@ -101,12 +115,13 @@ int netdev_nl_dev_get_doit(struct sk_buff *skb, struct genl_info *info)
 
 int netdev_nl_dev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
+	struct netdev_nl_dump_ctx *ctx = netdev_dump_ctx(cb);
 	struct net *net = sock_net(skb->sk);
 	struct net_device *netdev;
 	int err = 0;
 
 	rtnl_lock();
-	for_each_netdev_dump(net, netdev, cb->args[0]) {
+	for_each_netdev_dump(net, netdev, ctx->ifindex) {
 		err = netdev_nl_dev_fill(netdev, skb, genl_info_dump(cb));
 		if (err < 0)
 			break;
@@ -119,14 +134,158 @@ int netdev_nl_dev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 	return skb->len;
 }
 
+static int
+netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi,
+			const struct genl_info *info)
+{
+	struct netdev_rx_queue *rx_queue, *rxq;
+	struct netdev_queue *tx_queue, *txq;
+	unsigned int rx_qid, tx_qid;
+	void *hdr;
+
+	if (!napi->dev)
+		return -EINVAL;
+
+	hdr = genlmsg_iput(rsp, info);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(rsp, NETDEV_A_NAPI_NAPI_ID, napi->napi_id))
+		goto nla_put_failure;
+
+	if (nla_put_u32(rsp, NETDEV_A_NAPI_IFINDEX, napi->dev->ifindex))
+		goto nla_put_failure;
+
+	list_for_each_entry_safe(rx_queue, rxq, &napi->napi_rxq_list, q_list) {
+		rx_qid = get_netdev_rx_queue_index(rx_queue);
+		if (nla_put_u32(rsp, NETDEV_A_NAPI_RX_QUEUES, rx_qid))
+			goto nla_put_failure;
+	}
+
+	list_for_each_entry_safe(tx_queue, txq, &napi->napi_txq_list, q_list) {
+		tx_qid = get_netdev_queue_index(tx_queue);
+		if (nla_put_u32(rsp, NETDEV_A_NAPI_TX_QUEUES, tx_qid))
+			goto nla_put_failure;
+	}
+
+	genlmsg_end(rsp, hdr);
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(rsp, hdr);
+	return -EMSGSIZE;
+}
+
+static int
+netdev_nl_napi_fill(struct net_device *netdev, struct sk_buff *rsp,
+		    const struct genl_info *info, u32 napi_id)
+{
+	struct napi_struct *napi, *n;
+
+	list_for_each_entry_safe(napi, n, &netdev->napi_list, dev_list) {
+		if (napi->napi_id == napi_id)
+			return netdev_nl_napi_fill_one(rsp, napi, info);
+	}
+	return -EINVAL;
+}
+
 int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	return -EOPNOTSUPP;
+	struct net_device *netdev;
+	struct sk_buff *rsp;
+	u32 napi_id;
+	int err;
+
+	if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_NAPI_NAPI_ID))
+		return -EINVAL;
+
+	napi_id = nla_get_u32(info->attrs[NETDEV_A_NAPI_NAPI_ID]);
+
+	rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!rsp)
+		return -ENOMEM;
+
+	rtnl_lock();
+
+	netdev = dev_get_by_napi_id(napi_id);
+	if (netdev)
+		err  = netdev_nl_napi_fill(netdev, rsp, info, napi_id);
+	else
+		err = -ENODEV;
+
+	rtnl_unlock();
+
+	if (err)
+		goto err_free_msg;
+
+	return genlmsg_reply(rsp, info);
+
+err_free_msg:
+	nlmsg_free(rsp);
+	return err;
+}
+
+static int
+netdev_nl_napi_dump_one(struct net_device *netdev, struct sk_buff *rsp,
+			const struct genl_info *info, int *start)
+{
+	struct napi_struct *napi, *n;
+	int err = 0;
+	int i = 0;
+
+	list_for_each_entry_safe(napi, n, &netdev->napi_list, dev_list) {
+		if (i < *start) {
+			i++;
+			continue;
+		}
+		err = netdev_nl_napi_fill_one(rsp, napi, info);
+		if (err)
+			break;
+		*start = ++i;
+	}
+	return err;
 }
 
 int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	return -EOPNOTSUPP;
+	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	struct netdev_nl_dump_ctx *ctx = netdev_dump_ctx(cb);
+	struct net *net = sock_net(skb->sk);
+	struct net_device *netdev;
+	int n_idx = ctx->napi_idx;
+	u32 ifindex = 0;
+	int err = 0;
+
+	if (info->info.attrs[NETDEV_A_NAPI_IFINDEX])
+		ifindex = nla_get_u32(info->info.attrs[NETDEV_A_NAPI_IFINDEX]);
+
+	rtnl_lock();
+	if (ifindex) {
+		netdev = __dev_get_by_index(net, ifindex);
+		if (netdev)
+			err = netdev_nl_napi_dump_one(netdev, skb,
+						      genl_info_dump(cb),
+						      &n_idx);
+		else
+			err = -ENODEV;
+	} else {
+		for_each_netdev_dump(net, netdev, ctx->ifindex) {
+			err = netdev_nl_napi_dump_one(netdev, skb,
+						      genl_info_dump(cb),
+						      &n_idx);
+			if (!err)
+				n_idx = 0;
+			if (err < 0)
+				break;
+		}
+	}
+	rtnl_unlock();
+
+	if (err != -EMSGSIZE)
+		return err;
+
+	ctx->napi_idx = n_idx;
+	return skb->len;
 }
 
 static int netdev_genl_netdevice_event(struct notifier_block *nb,

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