From: Or Har-Toov <redacted>

Add support for userspace to query resources registered on devlink
ports, allowing drivers to expose per-port resource limits and usage.

Example output:

 $ devlink port resource show
 pci/0000:03:00.0/196608:
   name max_SFs size 20 unit entry
 pci/0000:03:00.1/262144:
   name max_SFs size 20 unit entry

 $ devlink port resource show pci/0000:03:00.0/196608
 pci/0000:03:00.0/196608:
   name max_SFs size 20 unit entry

Signed-off-by: Or Har-Toov <redacted>
Reviewed-by: Shay Drori <redacted>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
Documentation/netlink/specs/devlink.yaml |  23 ++++++
include/uapi/linux/devlink.h             |   3 +
net/devlink/netlink.c                    |   2 +-
net/devlink/netlink_gen.c                |  32 ++++++-
net/devlink/netlink_gen.h                |   6 +-
net/devlink/resource.c                   | 101 +++++++++++++++++++++++
6 files changed, 164 insertions(+), 3 deletions(-)

diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml
index 837112da6738..0290db1b8393 100644
--- a/Documentation/netlink/specs/devlink.yaml
+++ b/Documentation/netlink/specs/devlink.yaml

@@ -2336,3 +2336,26 @@ operations:
            - bus-name
            - dev-name
            - port-index
+
+    -
+      name: port-resource-get
+      doc: Get port resources.
+      attribute-set: devlink
+      dont-validate: [strict]
+      do:
+        pre: devlink-nl-pre-doit-port
+        post: devlink-nl-post-doit
+        request:
+          value: 85
+          attributes: *port-id-attrs
+        reply: &port-resource-get-reply
+          value: 85
+          attributes:
+            - bus-name
+            - dev-name
+            - port-index
+            - resource-list
+      dump:
+        request:
+          attributes: *dev-id-attrs
+        reply: *port-resource-get-reply

diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index e7d6b6d13470..1cabd1f6cba0 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h

@@ -141,6 +141,9 @@ enum devlink_command {

	DEVLINK_CMD_NOTIFY_FILTER_SET,

+	DEVLINK_CMD_PORT_RESOURCE_GET,	/* can dump */
+	DEVLINK_CMD_PORT_RESOURCE_SET,
+
	/* add new commands above here */
	__DEVLINK_CMD_MAX,
	DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1

diff --git a/net/devlink/netlink.c b/net/devlink/netlink.c
index 593605c1b1ef..c78c31779622 100644
--- a/net/devlink/netlink.c
+++ b/net/devlink/netlink.c

@@ -367,7 +367,7 @@ struct genl_family devlink_nl_family __ro_after_init = {

	.module		= THIS_MODULE,
	.split_ops	= devlink_nl_ops,
	.n_split_ops	= ARRAY_SIZE(devlink_nl_ops),
-	.resv_start_op	= DEVLINK_CMD_SELFTESTS_RUN + 1,
+	.resv_start_op	= DEVLINK_CMD_PORT_RESOURCE_GET + 1,
	.mcgrps		= devlink_nl_mcgrps,
	.n_mcgrps	= ARRAY_SIZE(devlink_nl_mcgrps),
	.sock_priv_size		= sizeof(struct devlink_nl_sock_priv),

diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
index f4c61c2b4f22..692d7862183a 100644
--- a/net/devlink/netlink_gen.c
+++ b/net/devlink/netlink_gen.c

@@ -604,8 +604,21 @@ static const struct nla_policy devlink_notify_filter_set_nl_policy[DEVLINK_ATTR_

	[DEVLINK_ATTR_PORT_INDEX] = { .type = NLA_U32, },
};

+/* DEVLINK_CMD_PORT_RESOURCE_GET - do */
+static const struct nla_policy devlink_port_resource_get_do_nl_policy[DEVLINK_ATTR_PORT_INDEX + 1] = {
+	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
+	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
+	[DEVLINK_ATTR_PORT_INDEX] = { .type = NLA_U32, },
+};
+
+/* DEVLINK_CMD_PORT_RESOURCE_GET - dump */
+static const struct nla_policy devlink_port_resource_get_dump_nl_policy[DEVLINK_ATTR_DEV_NAME + 1] = {
+	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
+	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
+};
+
/* Ops table for devlink */
-const struct genl_split_ops devlink_nl_ops[74] = {
+const struct genl_split_ops devlink_nl_ops[76] = {
	{
		.cmd		= DEVLINK_CMD_GET,
		.validate	= GENL_DONT_VALIDATE_STRICT,

@@ -1284,4 +1297,21 @@ const struct genl_split_ops devlink_nl_ops[74] = {

		.maxattr	= DEVLINK_ATTR_PORT_INDEX,
		.flags		= GENL_CMD_CAP_DO,
	},
+	{
+		.cmd		= DEVLINK_CMD_PORT_RESOURCE_GET,
+		.validate	= GENL_DONT_VALIDATE_STRICT,
+		.pre_doit	= devlink_nl_pre_doit_port,
+		.doit		= devlink_nl_port_resource_get_doit,
+		.post_doit	= devlink_nl_post_doit,
+		.policy		= devlink_port_resource_get_do_nl_policy,
+		.maxattr	= DEVLINK_ATTR_PORT_INDEX,
+		.flags		= GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= DEVLINK_CMD_PORT_RESOURCE_GET,
+		.dumpit		= devlink_nl_port_resource_get_dumpit,
+		.policy		= devlink_port_resource_get_dump_nl_policy,
+		.maxattr	= DEVLINK_ATTR_DEV_NAME,
+		.flags		= GENL_CMD_CAP_DUMP,
+	},
};

diff --git a/net/devlink/netlink_gen.h b/net/devlink/netlink_gen.h
index 2817d53a0eba..204a665d2fd2 100644
--- a/net/devlink/netlink_gen.h
+++ b/net/devlink/netlink_gen.h

@@ -18,7 +18,7 @@ extern const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_RATE_TC_

extern const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1];

/* Ops table for devlink */
-extern const struct genl_split_ops devlink_nl_ops[74];
+extern const struct genl_split_ops devlink_nl_ops[76];

int devlink_nl_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
			struct genl_info *info);

@@ -146,5 +146,9 @@ int devlink_nl_selftests_get_dumpit(struct sk_buff *skb,

int devlink_nl_selftests_run_doit(struct sk_buff *skb, struct genl_info *info);
int devlink_nl_notify_filter_set_doit(struct sk_buff *skb,
				      struct genl_info *info);
+int devlink_nl_port_resource_get_doit(struct sk_buff *skb,
+				      struct genl_info *info);
+int devlink_nl_port_resource_get_dumpit(struct sk_buff *skb,
+					struct netlink_callback *cb);

#endif /* _LINUX_DEVLINK_GEN_H */

diff --git a/net/devlink/resource.c b/net/devlink/resource.c
index 1b06a1f408fa..42ad7c96a740 100644
--- a/net/devlink/resource.c
+++ b/net/devlink/resource.c

@@ -227,6 +227,7 @@ static int devlink_resource_fill(struct genl_info *info,

				 struct list_head *resource_list,
				 enum devlink_command cmd, int flags)
{
+	struct devlink_port *devlink_port = info->user_ptr[1];
	struct devlink *devlink = info->user_ptr[0];
	struct devlink_resource *resource;
	struct nlattr *resources_attr;

@@ -257,6 +258,10 @@ static int devlink_resource_fill(struct genl_info *info,

	if (devlink_nl_put_handle(skb, devlink))
		goto nla_put_failure;

+	if (devlink_port && nla_put_u32(skb, DEVLINK_ATTR_PORT_INDEX,
+					devlink_port->index))
+		goto nla_put_failure;
+
	resources_attr = nla_nest_start_noflag(skb,
					       DEVLINK_ATTR_RESOURCE_LIST);
	if (!resources_attr)

@@ -576,3 +581,99 @@ void devl_port_resources_unregister(struct devlink_port *devlink_port)

				    &devlink_port->resource_list);
}
EXPORT_SYMBOL_GPL(devl_port_resources_unregister);
+
+static int devlink_nl_port_resource_fill(struct sk_buff *msg,
+					 struct devlink_port *devlink_port,
+					 enum devlink_command cmd,
+					 u32 portid, u32 seq, int flags)
+{
+	struct devlink *devlink = devlink_port->devlink;
+	struct devlink_resource *resource;
+	struct nlattr *resources_attr;
+	void *hdr;
+
+	if (list_empty(&devlink_port->resource_list))
+		return 0;
+
+	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (devlink_nl_put_handle(msg, devlink))
+		goto nla_put_failure;
+	if (nla_put_u32(msg, DEVLINK_ATTR_PORT_INDEX, devlink_port->index))
+		goto nla_put_failure;
+
+	resources_attr = nla_nest_start_noflag(msg, DEVLINK_ATTR_RESOURCE_LIST);
+	if (!resources_attr)
+		goto nla_put_failure;
+
+	list_for_each_entry(resource, &devlink_port->resource_list, list) {
+		if (devlink_resource_put(devlink, msg, resource)) {
+			nla_nest_cancel(msg, resources_attr);
+			goto nla_put_failure;
+		}
+	}
+	nla_nest_end(msg, resources_attr);
+	genlmsg_end(msg, hdr);
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;