[RFC net-next v4 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 | 11 ++++++
 include/uapi/linux/netdev.h             |  1 +
 net/core/netdev-genl-gen.c              | 14 ++++++++
 net/core/netdev-genl-gen.h              |  1 +
 net/core/netdev-genl.c                  | 45 +++++++++++++++++++++++++
 tools/include/uapi/linux/netdev.h       |  1 +
 6 files changed, 73 insertions(+)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index bf13613eaa0d..7f8d2489c68c 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -690,6 +690,17 @@ operations:
         reply:
           attributes:
             - id
+    -
+      name: napi-set
+      doc: Set configurable NAPI instance settings.
+      attribute-set: napi
+      flags: [ admin-perm ]
+      do:
+        request:
+          attributes:
+            - napi-id
+            - defer-hard-irqs
+            - gro-flush-timeout
 
 kernel-family:
   headers: [ "linux/list.h"]
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index cacd33359c76..e3ebb49f60d2 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -201,6 +201,7 @@ enum {
 	NETDEV_CMD_NAPI_GET,
 	NETDEV_CMD_QSTATS_GET,
 	NETDEV_CMD_BIND_RX,
+	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 b28424ae06d5..901c6f65b735 100644
--- a/net/core/netdev-genl-gen.c
+++ b/net/core/netdev-genl-gen.c
@@ -87,6 +87,13 @@ static const struct nla_policy netdev_bind_rx_nl_policy[NETDEV_A_DMABUF_FD + 1]
 	[NETDEV_A_DMABUF_QUEUES] = NLA_POLICY_NESTED(netdev_queue_id_nl_policy),
 };
 
+/* 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_ID] = { .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[] = {
 	{
@@ -171,6 +178,13 @@ static const struct genl_split_ops netdev_nl_ops[] = {
 		.maxattr	= NETDEV_A_DMABUF_FD,
 		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
 	},
+	{
+		.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 8cda334fd042..85e6d7c95ada 100644
--- a/net/core/netdev-genl-gen.h
+++ b/net/core/netdev-genl-gen.h
@@ -30,6 +30,7 @@ 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);
 int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info);
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 64e5e4cee60d..59523318d620 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -303,6 +303,51 @@ 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_struct *napi, struct genl_info *info)
+{
+	u64 gro_flush_timeout = 0;
+	u32 defer = 0;
+
+	if (info->attrs[NETDEV_A_NAPI_DEFER_HARD_IRQS]) {
+		defer = nla_get_u32(info->attrs[NETDEV_A_NAPI_DEFER_HARD_IRQS]);
+		napi_set_defer_hard_irqs(napi, defer);
+	}
+
+	if (info->attrs[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT]) {
+		gro_flush_timeout = nla_get_uint(info->attrs[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT]);
+		napi_set_gro_flush_timeout(napi, gro_flush_timeout);
+	}
+
+	return 0;
+}
+
+int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct napi_struct *napi;
+	unsigned int 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]);
+
+	rtnl_lock();
+
+	napi = napi_by_id(napi_id);
+	if (napi) {
+		err = netdev_nl_napi_set_config(napi, info);
+	} else {
+		NL_SET_BAD_ATTR(info->extack, info->attrs[NETDEV_A_NAPI_ID]);
+		err = -ENOENT;
+	}
+
+	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 cacd33359c76..e3ebb49f60d2 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -201,6 +201,7 @@ enum {
 	NETDEV_CMD_NAPI_GET,
 	NETDEV_CMD_QSTATS_GET,
 	NETDEV_CMD_BIND_RX,
+	NETDEV_CMD_NAPI_SET,
 
 	__NETDEV_CMD_MAX,
 	NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
-- 
2.25.1