[RFC net-next v2 6/9] netdev-genl: Support setting per-NAPI config values

[Joe Damato <jdamato@fastly.com>]

Add support to set per-NAPI defer_hard_irqs and gro_flush_timeout.

Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 Documentation/netlink/specs/netdev.yaml | 12 ++++++
 include/uapi/linux/netdev.h             |  1 +
 net/core/netdev-genl-gen.c              | 15 +++++++
 net/core/netdev-genl-gen.h              |  1 +
 net/core/netdev-genl.c                  | 52 +++++++++++++++++++++++++
 tools/include/uapi/linux/netdev.h       |  1 +
 6 files changed, 82 insertions(+)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index 3034c480d0b4..7c0c25e5b808 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -642,6 +642,18 @@ operations:
             - rx-bytes
             - tx-packets
             - tx-bytes
+    -
+      name: napi-set
+      doc: Set configurable NAPI instance settings.
+      attribute-set: napi
+      flags: [ admin-perm ]
+      do:
+        request:
+          attributes:
+            - ifindex
+            - index
+            - defer-hard-irqs
+            - gro-flush-timeout
 
 mcast-groups:
   list:
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index fd02b5b3b081..4e6941b45f3e 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -189,6 +189,7 @@ enum {
 	NETDEV_CMD_QUEUE_GET,
 	NETDEV_CMD_NAPI_GET,
 	NETDEV_CMD_QSTATS_GET,
+	NETDEV_CMD_NAPI_SET,
 
 	__NETDEV_CMD_MAX,
 	NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c
index 8350a0afa9ec..209c56cf08f1 100644
--- a/net/core/netdev-genl-gen.c
+++ b/net/core/netdev-genl-gen.c
@@ -74,6 +74,14 @@ static const struct nla_policy netdev_qstats_get_nl_policy[NETDEV_A_QSTATS_SCOPE
 	[NETDEV_A_QSTATS_SCOPE] = NLA_POLICY_MASK(NLA_UINT, 0x1),
 };
 
+/* NETDEV_CMD_NAPI_SET - set */
+static const struct nla_policy netdev_napi_set_nl_policy[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT + 1] = {
+	[NETDEV_A_NAPI_IFINDEX] = { .type = NLA_U32, },
+	[NETDEV_A_NAPI_INDEX] = { .type = NLA_U32, },
+	[NETDEV_A_NAPI_DEFER_HARD_IRQS] = { .type = NLA_S32 },
+	[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT] = { .type = NLA_UINT },
+};
+
 /* Ops table for netdev */
 static const struct genl_split_ops netdev_nl_ops[] = {
 	{
@@ -151,6 +159,13 @@ static const struct genl_split_ops netdev_nl_ops[] = {
 		.maxattr	= NETDEV_A_QSTATS_SCOPE,
 		.flags		= GENL_CMD_CAP_DUMP,
 	},
+	{
+		.cmd		= NETDEV_CMD_NAPI_SET,
+		.doit		= netdev_nl_napi_set_doit,
+		.policy		= netdev_napi_set_nl_policy,
+		.maxattr	= NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
 };
 
 static const struct genl_multicast_group netdev_nl_mcgrps[] = {
diff --git a/net/core/netdev-genl-gen.h b/net/core/netdev-genl-gen.h
index 4db40fd5b4a9..b70cb0f20acb 100644
--- a/net/core/netdev-genl-gen.h
+++ b/net/core/netdev-genl-gen.h
@@ -28,6 +28,7 @@ int netdev_nl_queue_get_dumpit(struct sk_buff *skb,
 			       struct netlink_callback *cb);
 int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info);
 int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info);
 int netdev_nl_qstats_get_dumpit(struct sk_buff *skb,
 				struct netlink_callback *cb);
 
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 68ec8265567d..fca1670706cc 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -303,6 +303,58 @@ int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 	return err;
 }
 
+static int
+netdev_nl_napi_set_config(struct napi_storage *napi_storage, struct genl_info *info)
+{
+	u64 gro_flush_timeout = 0;
+	int defer = 0;
+
+	if (info->attrs[NETDEV_A_NAPI_DEFER_HARD_IRQS]) {
+		defer = nla_get_s32(info->attrs[NETDEV_A_NAPI_DEFER_HARD_IRQS]);
+		WRITE_ONCE(napi_storage->defer_hard_irqs, defer);
+	}
+
+	if (info->attrs[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT]) {
+		gro_flush_timeout = nla_get_uint(info->attrs[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT]);
+		WRITE_ONCE(napi_storage->gro_flush_timeout, gro_flush_timeout);
+	}
+
+	return 0;
+}
+
+int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct napi_storage *napi_storage;
+	struct net_device *netdev;
+	u32 ifindex;
+	u32 index;
+	int err;
+
+	if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_NAPI_IFINDEX))
+		return -EINVAL;
+
+	if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_NAPI_INDEX))
+		return -EINVAL;
+
+	ifindex = nla_get_u32(info->attrs[NETDEV_A_NAPI_IFINDEX]);
+	index = nla_get_u32(info->attrs[NETDEV_A_NAPI_INDEX]);
+
+	rtnl_lock();
+
+	netdev = __dev_get_by_index(genl_info_net(info), ifindex);
+	if (netdev) {
+		napi_storage = &netdev->napi_storage[index];
+		err = netdev_nl_napi_set_config(napi_storage, info);
+	} else {
+		NL_SET_BAD_ATTR(info->extack, info->attrs[NETDEV_A_NAPI_IFINDEX]);
+		err = -ENODEV;
+	}
+
+	rtnl_unlock();
+
+	return err;
+}
+
 static int
 netdev_nl_queue_fill_one(struct sk_buff *rsp, struct net_device *netdev,
 			 u32 q_idx, u32 q_type, const struct genl_info *info)
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index b088a34e9254..4c5bfbc85504 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -188,6 +188,7 @@ enum {
 	NETDEV_CMD_QUEUE_GET,
 	NETDEV_CMD_NAPI_GET,
 	NETDEV_CMD_QSTATS_GET,
+	NETDEV_CMD_NAPI_SET,
 
 	__NETDEV_CMD_MAX,
 	NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
-- 
2.25.1