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
parameters can be retrieved this way.

Signed-off-by: Amritha Nambiar <amritha.nambiar@intel.com>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Link: https://lore.kernel.org/r/170147333637.5260.14807433239805550815.stgit@anambiarhost.jf.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 119 insertions, 2 deletions

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 4c8ea6a4f015..d55c92f9f26c 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -8,13 +8,16 @@
 #include <net/xdp.h>
 #include <net/xdp_sock.h>
 #include <net/netdev_rx_queue.h>
+#include <net/busy_poll.h>
 
 #include "netdev-genl-gen.h"
+#include "dev.h"
 
 struct netdev_nl_dump_ctx {
 	unsigned long	ifindex;
 	unsigned int	rxq_idx;
 	unsigned int	txq_idx;
+	unsigned int	napi_id;
 };
 
 static struct netdev_nl_dump_ctx *netdev_dump_ctx(struct netlink_callback *cb)
@@ -155,14 +158,128 @@ 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)
+{
+	void *hdr;
+
+	if (WARN_ON_ONCE(!napi->dev))
+		return -EINVAL;
+	if (!(napi->dev->flags & IFF_UP))
+		return 0;
+
+	hdr = genlmsg_iput(rsp, info);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (napi->napi_id >= MIN_NAPI_ID &&
+	    nla_put_u32(rsp, NETDEV_A_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;
+
+	genlmsg_end(rsp, hdr);
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(rsp, hdr);
+	return -EMSGSIZE;
+}
+
 int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	return -EOPNOTSUPP;
+	struct napi_struct *napi;
+	struct sk_buff *rsp;
+	u32 napi_id;
+	int err;
+
+	if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_NAPI_ID))
+		return -EINVAL;
+
+	napi_id = nla_get_u32(info->attrs[NETDEV_A_NAPI_ID]);
+
+	rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!rsp)
+		return -ENOMEM;
+
+	rtnl_lock();
+
+	napi = napi_by_id(napi_id);
+	if (napi)
+		err = netdev_nl_napi_fill_one(rsp, napi, info);
+	else
+		err = -EINVAL;
+
+	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,
+			struct netdev_nl_dump_ctx *ctx)
+{
+	struct napi_struct *napi;
+	int err = 0;
+
+	if (!(netdev->flags & IFF_UP))
+		return err;
+
+	list_for_each_entry(napi, &netdev->napi_list, dev_list) {
+		if (ctx->napi_id && napi->napi_id >= ctx->napi_id)
+			continue;
+
+		err = netdev_nl_napi_fill_one(rsp, napi, info);
+		if (err)
+			return err;
+		ctx->napi_id = napi->napi_id;
+	}
+	return err;
 }
 
 int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	return -EOPNOTSUPP;
+	struct netdev_nl_dump_ctx *ctx = netdev_dump_ctx(cb);
+	const struct genl_info *info = genl_info_dump(cb);
+	struct net *net = sock_net(skb->sk);
+	struct net_device *netdev;
+	u32 ifindex = 0;
+	int err = 0;
+
+	if (info->attrs[NETDEV_A_NAPI_IFINDEX])
+		ifindex = nla_get_u32(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, info, ctx);
+		else
+			err = -ENODEV;
+	} else {
+		for_each_netdev_dump(net, netdev, ctx->ifindex) {
+			err = netdev_nl_napi_dump_one(netdev, skb, info, ctx);
+			if (err < 0)
+				break;
+			ctx->napi_id = 0;
+		}
+	}
+	rtnl_unlock();
+
+	if (err != -EMSGSIZE)
+		return err;
+
+	return skb->len;
 }
 
 static int