[PATCH net-next V9 1/5] devlink: Extend devlink rate API with traffic classes bandwidth management

[Tariq Toukan <tariqt@nvidia.com>]

From: Carolina Jubran <cjubran@nvidia.com>

Introduce support for specifying bandwidth proportions between traffic
classes (TC) in the devlink-rate API. This new option allows users to
allocate bandwidth across multiple traffic classes in a single command.

This feature provides a more granular control over traffic management,
especially for scenarios requiring Enhanced Transmission Selection.

Users can now define a specific bandwidth share for each traffic class,
such as allocating 20% for TC0 (TCP/UDP) and 80% for TC5 (RoCE).

Example:
DEV=pci/0000:08:00.0

$ devlink port function rate add $DEV/vfs_group tx_share 10Gbit \
  tx_max 50Gbit tc-bw 0:20 1:0 2:0 3:0 4:0 5:80 6:0 7:0

$ devlink port function rate set $DEV/vfs_group \
  tc-bw 0:20 1:0 2:0 3:0 4:0 5:20 6:60 7:0

Example usage with ynl:

./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml \
  --do rate-set --json '{
  "bus-name": "pci",
  "dev-name": "0000:08:00.0",
  "port-index": 1,
  "rate-tc-bws": [
    {"rate-tc-index": 0, "rate-tc-bw": 50},
    {"rate-tc-index": 1, "rate-tc-bw": 50},
    {"rate-tc-index": 2, "rate-tc-bw": 0},
    {"rate-tc-index": 3, "rate-tc-bw": 0},
    {"rate-tc-index": 4, "rate-tc-bw": 0},
    {"rate-tc-index": 5, "rate-tc-bw": 0},
    {"rate-tc-index": 6, "rate-tc-bw": 0},
    {"rate-tc-index": 7, "rate-tc-bw": 0}
  ]
}'

./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml \
  --do rate-get --json '{
  "bus-name": "pci",
  "dev-name": "0000:08:00.0",
  "port-index": 1
}'

output for rate-get:
{'bus-name': 'pci',
 'dev-name': '0000:08:00.0',
 'port-index': 1,
 'rate-tc-bws': [{'rate-tc-bw': 50, 'rate-tc-index': 0},
                 {'rate-tc-bw': 50, 'rate-tc-index': 1},
                 {'rate-tc-bw': 0, 'rate-tc-index': 2},
                 {'rate-tc-bw': 0, 'rate-tc-index': 3},
                 {'rate-tc-bw': 0, 'rate-tc-index': 4},
                 {'rate-tc-bw': 0, 'rate-tc-index': 5},
                 {'rate-tc-bw': 0, 'rate-tc-index': 6},
                 {'rate-tc-bw': 0, 'rate-tc-index': 7}],
 'rate-tx-max': 0,
 'rate-tx-priority': 0,
 'rate-tx-share': 0,
 'rate-tx-weight': 0,
 'rate-type': 'leaf'}

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 Documentation/netlink/specs/devlink.yaml      |  36 ++++-
 .../networking/devlink/devlink-port.rst       |   7 +
 include/net/devlink.h                         |   6 +
 include/uapi/linux/devlink.h                  |   7 +
 net/devlink/netlink_gen.c                     |  15 ++-
 net/devlink/netlink_gen.h                     |   1 +
 net/devlink/rate.c                            | 127 ++++++++++++++++++
 7 files changed, 194 insertions(+), 5 deletions(-)

diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml
index 05fee1b7fe19..d5d40193dac5 100644
--- a/Documentation/netlink/specs/devlink.yaml
+++ b/Documentation/netlink/specs/devlink.yaml
@@ -224,6 +224,11 @@ definitions:
         value: 10
       -
         name: binary
+  -
+    name:  devlink-rate-tc-index-max
+    header: uapi/linux/devlink.h
+    type: const
+    value: 7
 
 attribute-sets:
   -
@@ -844,7 +849,26 @@ attribute-sets:
       -
         name: region-direct
         type: flag
-
+      -
+        name: rate-tc-bws
+        type: nest
+        multi-attr: true
+        nested-attributes: dl-rate-tc-bws
+      -
+        name: rate-tc-index
+        type: u8
+        checks:
+          min: 0
+          max: devlink-rate-tc-index-max
+      -
+        name: rate-tc-bw
+        type: u32
+        doc: |
+             Specifies the bandwidth allocation for the Traffic Class as a
+             percentage.
+        checks:
+          min: 0
+          max: 100
   -
     name: dl-dev-stats
     subset-of: devlink
@@ -1249,6 +1273,14 @@ attribute-sets:
       -
         name: flash
         type: flag
+  -
+    name: dl-rate-tc-bws
+    subset-of: devlink
+    attributes:
+      -
+       name: rate-tc-index
+      -
+       name: rate-tc-bw
 
 operations:
   enum-model: directional
@@ -2174,6 +2206,7 @@ operations:
             - rate-tx-priority
             - rate-tx-weight
             - rate-parent-node-name
+            - rate-tc-bws
 
     -
       name: rate-new
@@ -2194,6 +2227,7 @@ operations:
             - rate-tx-priority
             - rate-tx-weight
             - rate-parent-node-name
+            - rate-tc-bws
 
     -
       name: rate-del
diff --git a/Documentation/networking/devlink/devlink-port.rst b/Documentation/networking/devlink/devlink-port.rst
index 9d22d41a7cd1..bc3b41ac2d51 100644
--- a/Documentation/networking/devlink/devlink-port.rst
+++ b/Documentation/networking/devlink/devlink-port.rst
@@ -418,6 +418,13 @@ API allows to configure following rate object's parameters:
   to all node children limits. ``tx_max`` is an upper limit for children.
   ``tx_share`` is a total bandwidth distributed among children.
 
+``tc_bw``
+  Allow users to set the bandwidth allocation per traffic class on rate
+  objects. This enables fine-grained QoS configurations by assigning specific
+  bandwidth percentages to different traffic classes. When applied to a
+  non-leaf node, tc_bw determines how bandwidth is shared among its child
+  elements.
+
 ``tx_priority`` and ``tx_weight`` can be used simultaneously. In that case
 nodes with the same priority form a WFQ subgroup in the sibling group
 and arbitration among them is based on assigned weights.
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 0091f23a40f7..135f7382386e 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -118,6 +118,8 @@ struct devlink_rate {
 
 	u32 tx_priority;
 	u32 tx_weight;
+
+	u32 tc_bw[DEVLINK_RATE_TCS_MAX];
 };
 
 struct devlink_port {
@@ -1482,6 +1484,8 @@ struct devlink_ops {
 					 u32 tx_priority, struct netlink_ext_ack *extack);
 	int (*rate_leaf_tx_weight_set)(struct devlink_rate *devlink_rate, void *priv,
 				       u32 tx_weight, struct netlink_ext_ack *extack);
+	int (*rate_leaf_tc_bw_set)(struct devlink_rate *devlink_rate, void *priv,
+				   u32 *tc_bw, struct netlink_ext_ack *extack);
 	int (*rate_node_tx_share_set)(struct devlink_rate *devlink_rate, void *priv,
 				      u64 tx_share, struct netlink_ext_ack *extack);
 	int (*rate_node_tx_max_set)(struct devlink_rate *devlink_rate, void *priv,
@@ -1490,6 +1494,8 @@ struct devlink_ops {
 					 u32 tx_priority, struct netlink_ext_ack *extack);
 	int (*rate_node_tx_weight_set)(struct devlink_rate *devlink_rate, void *priv,
 				       u32 tx_weight, struct netlink_ext_ack *extack);
+	int (*rate_node_tc_bw_set)(struct devlink_rate *devlink_rate, void *priv,
+				   u32 *tc_bw, struct netlink_ext_ack *extack);
 	int (*rate_node_new)(struct devlink_rate *rate_node, void **priv,
 			     struct netlink_ext_ack *extack);
 	int (*rate_node_del)(struct devlink_rate *rate_node, void *priv,
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index a5ee0f13740a..6932a05c694d 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -221,6 +221,9 @@ enum devlink_port_flavour {
 				      */
 };
 
+#define DEVLINK_RATE_TCS_MAX 8
+#define DEVLINK_RATE_TC_INDEX_MAX (DEVLINK_RATE_TCS_MAX - 1)
+
 enum devlink_rate_type {
 	DEVLINK_RATE_TYPE_LEAF,
 	DEVLINK_RATE_TYPE_NODE,
@@ -629,6 +632,10 @@ enum devlink_attr {
 
 	DEVLINK_ATTR_REGION_DIRECT,		/* flag */
 
+	DEVLINK_ATTR_RATE_TC_BWS,		/* nested */
+	DEVLINK_ATTR_RATE_TC_INDEX,		/* u8 */
+	DEVLINK_ATTR_RATE_TC_BW,		/* u32 */
+
 	/* Add new attributes above here, update the spec in
 	 * Documentation/netlink/specs/devlink.yaml and re-generate
 	 * net/devlink/netlink_gen.c.
diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
index e340d955cf3b..6d5b8296b049 100644
--- a/net/devlink/netlink_gen.c
+++ b/net/devlink/netlink_gen.c
@@ -45,6 +45,11 @@ const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_
 	[DEVLINK_PORT_FN_ATTR_CAPS] = NLA_POLICY_BITFIELD32(15),
 };
 
+const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_ATTR_RATE_TC_BW + 1] = {
+	[DEVLINK_ATTR_RATE_TC_INDEX] = NLA_POLICY_RANGE(NLA_U8, 0, DEVLINK_RATE_TC_INDEX_MAX),
+	[DEVLINK_ATTR_RATE_TC_BW] = NLA_POLICY_RANGE(NLA_U32, 0, 100),
+};
+
 const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1] = {
 	[DEVLINK_ATTR_SELFTEST_ID_FLASH] = { .type = NLA_FLAG, },
 };
@@ -523,7 +528,7 @@ static const struct nla_policy devlink_rate_get_dump_nl_policy[DEVLINK_ATTR_DEV_
 };
 
 /* DEVLINK_CMD_RATE_SET - do */
-static const struct nla_policy devlink_rate_set_nl_policy[DEVLINK_ATTR_RATE_TX_WEIGHT + 1] = {
+static const struct nla_policy devlink_rate_set_nl_policy[DEVLINK_ATTR_RATE_TC_BWS + 1] = {
 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_RATE_NODE_NAME] = { .type = NLA_NUL_STRING, },
@@ -532,10 +537,11 @@ static const struct nla_policy devlink_rate_set_nl_policy[DEVLINK_ATTR_RATE_TX_W
 	[DEVLINK_ATTR_RATE_TX_PRIORITY] = { .type = NLA_U32, },
 	[DEVLINK_ATTR_RATE_TX_WEIGHT] = { .type = NLA_U32, },
 	[DEVLINK_ATTR_RATE_PARENT_NODE_NAME] = { .type = NLA_NUL_STRING, },
+	[DEVLINK_ATTR_RATE_TC_BWS] = NLA_POLICY_NESTED(devlink_dl_rate_tc_bws_nl_policy),
 };
 
 /* DEVLINK_CMD_RATE_NEW - do */
-static const struct nla_policy devlink_rate_new_nl_policy[DEVLINK_ATTR_RATE_TX_WEIGHT + 1] = {
+static const struct nla_policy devlink_rate_new_nl_policy[DEVLINK_ATTR_RATE_TC_BWS + 1] = {
 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_RATE_NODE_NAME] = { .type = NLA_NUL_STRING, },
@@ -544,6 +550,7 @@ static const struct nla_policy devlink_rate_new_nl_policy[DEVLINK_ATTR_RATE_TX_W
 	[DEVLINK_ATTR_RATE_TX_PRIORITY] = { .type = NLA_U32, },
 	[DEVLINK_ATTR_RATE_TX_WEIGHT] = { .type = NLA_U32, },
 	[DEVLINK_ATTR_RATE_PARENT_NODE_NAME] = { .type = NLA_NUL_STRING, },
+	[DEVLINK_ATTR_RATE_TC_BWS] = NLA_POLICY_NESTED(devlink_dl_rate_tc_bws_nl_policy),
 };
 
 /* DEVLINK_CMD_RATE_DEL - do */
@@ -1191,7 +1198,7 @@ const struct genl_split_ops devlink_nl_ops[74] = {
 		.doit		= devlink_nl_rate_set_doit,
 		.post_doit	= devlink_nl_post_doit,
 		.policy		= devlink_rate_set_nl_policy,
-		.maxattr	= DEVLINK_ATTR_RATE_TX_WEIGHT,
+		.maxattr	= DEVLINK_ATTR_RATE_TC_BWS,
 		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
 	},
 	{
@@ -1201,7 +1208,7 @@ const struct genl_split_ops devlink_nl_ops[74] = {
 		.doit		= devlink_nl_rate_new_doit,
 		.post_doit	= devlink_nl_post_doit,
 		.policy		= devlink_rate_new_nl_policy,
-		.maxattr	= DEVLINK_ATTR_RATE_TX_WEIGHT,
+		.maxattr	= DEVLINK_ATTR_RATE_TC_BWS,
 		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
 	},
 	{
diff --git a/net/devlink/netlink_gen.h b/net/devlink/netlink_gen.h
index 8f2bd50ddf5e..fb733b5d4ff1 100644
--- a/net/devlink/netlink_gen.h
+++ b/net/devlink/netlink_gen.h
@@ -13,6 +13,7 @@
 
 /* Common nested types */
 extern const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_CAPS + 1];
+extern const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_ATTR_RATE_TC_BW + 1];
 extern const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1];
 
 /* Ops table for devlink */
diff --git a/net/devlink/rate.c b/net/devlink/rate.c
index 8828ffaf6cbc..56ee4aca2eff 100644
--- a/net/devlink/rate.c
+++ b/net/devlink/rate.c
@@ -80,6 +80,29 @@ devlink_rate_get_from_info(struct devlink *devlink, struct genl_info *info)
 		return ERR_PTR(-EINVAL);
 }
 
+static int devlink_rate_put_tc_bws(struct sk_buff *msg, u32 *tc_bw)
+{
+	struct nlattr *nla_tc_bw;
+	int i;
+
+	for (i = 0; i < DEVLINK_RATE_TCS_MAX; i++) {
+		nla_tc_bw = nla_nest_start(msg, DEVLINK_ATTR_RATE_TC_BWS);
+		if (!nla_tc_bw)
+			return -EMSGSIZE;
+
+		if (nla_put_u8(msg, DEVLINK_ATTR_RATE_TC_INDEX, i) ||
+		    nla_put_u32(msg, DEVLINK_ATTR_RATE_TC_BW, tc_bw[i]))
+			goto nla_put_failure;
+
+		nla_nest_end(msg, nla_tc_bw);
+	}
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, nla_tc_bw);
+	return -EMSGSIZE;
+}
+
 static int devlink_nl_rate_fill(struct sk_buff *msg,
 				struct devlink_rate *devlink_rate,
 				enum devlink_command cmd, u32 portid, u32 seq,
@@ -129,6 +152,9 @@ static int devlink_nl_rate_fill(struct sk_buff *msg,
 				   devlink_rate->parent->name))
 			goto nla_put_failure;
 
+	if (devlink_rate_put_tc_bws(msg, devlink_rate->tc_bw))
+		goto nla_put_failure;
+
 	genlmsg_end(msg, hdr);
 	return 0;
 
@@ -316,6 +342,89 @@ devlink_nl_rate_parent_node_set(struct devlink_rate *devlink_rate,
 	return 0;
 }
 
+static int devlink_nl_rate_tc_bw_parse(struct nlattr *parent_nest, u32 *tc_bw,
+				       unsigned long *bitmap, struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[DEVLINK_ATTR_MAX + 1];
+	u8 tc_index;
+
+	nla_parse_nested(tb, DEVLINK_ATTR_MAX, parent_nest, devlink_dl_rate_tc_bws_nl_policy,
+			 extack);
+	if (!tb[DEVLINK_ATTR_RATE_TC_INDEX]) {
+		NL_SET_ERR_ATTR_MISS(extack, parent_nest, DEVLINK_ATTR_RATE_TC_INDEX);
+		return -EINVAL;
+	}
+
+	tc_index = nla_get_u8(tb[DEVLINK_ATTR_RATE_TC_INDEX]);
+
+	if (!tb[DEVLINK_ATTR_RATE_TC_BW]) {
+		NL_SET_ERR_ATTR_MISS(extack, parent_nest, DEVLINK_ATTR_RATE_TC_BW);
+		return -EINVAL;
+	}
+
+	if (test_and_set_bit(tc_index, bitmap)) {
+		NL_SET_ERR_MSG_FMT(extack, "Duplicate traffic class index specified (%u)",
+				   tc_index);
+		return -EINVAL;
+	}
+
+	tc_bw[tc_index] = nla_get_u32(tb[DEVLINK_ATTR_RATE_TC_BW]);
+
+	return 0;
+}
+
+static int devlink_nl_rate_tc_bw_set(struct devlink_rate *devlink_rate,
+				     struct genl_info *info)
+{
+	DECLARE_BITMAP(bitmap, DEVLINK_RATE_TCS_MAX) = {};
+	struct devlink *devlink = devlink_rate->devlink;
+	const struct devlink_ops *ops = devlink->ops;
+	int rem, err = -EOPNOTSUPP, i, total = 0;
+	u32 tc_bw[DEVLINK_RATE_TCS_MAX] = {};
+	struct nlattr *attr;
+
+	nla_for_each_attr(attr, genlmsg_data(info->genlhdr),
+			  genlmsg_len(info->genlhdr), rem) {
+		if (nla_type(attr) == DEVLINK_ATTR_RATE_TC_BWS) {
+			err = devlink_nl_rate_tc_bw_parse(attr, tc_bw, bitmap, info->extack);
+			if (err)
+				return err;
+		}
+	}
+
+	for (i = 0; i < DEVLINK_RATE_TCS_MAX; i++) {
+		if (!test_bit(i, bitmap)) {
+			NL_SET_ERR_MSG_FMT(info->extack,
+					   "Bandwidth values must be specified for all %u traffic classes",
+					   DEVLINK_RATE_TCS_MAX);
+			return -EINVAL;
+		}
+
+		total += tc_bw[i];
+	}
+
+	if (total && total != 100) {
+		NL_SET_ERR_MSG_FMT(info->extack,
+				   "Sum of all traffic class bandwidth values must be 100, got %u",
+				   total);
+		return -EINVAL;
+	}
+
+	if (devlink_rate_is_leaf(devlink_rate))
+		err = ops->rate_leaf_tc_bw_set(devlink_rate, devlink_rate->priv, tc_bw,
+					       info->extack);
+	else if (devlink_rate_is_node(devlink_rate))
+		err = ops->rate_node_tc_bw_set(devlink_rate, devlink_rate->priv, tc_bw,
+					       info->extack);
+
+	if (err)
+		return err;
+
+	memcpy(devlink_rate->tc_bw, tc_bw, sizeof(tc_bw));
+
+	return 0;
+}
+
 static int devlink_nl_rate_set(struct devlink_rate *devlink_rate,
 			       const struct devlink_ops *ops,
 			       struct genl_info *info)
@@ -388,6 +497,12 @@ static int devlink_nl_rate_set(struct devlink_rate *devlink_rate,
 			return err;
 	}
 
+	if (attrs[DEVLINK_ATTR_RATE_TC_BWS]) {
+		err = devlink_nl_rate_tc_bw_set(devlink_rate, info);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 
@@ -423,6 +538,12 @@ static bool devlink_rate_set_ops_supported(const struct devlink_ops *ops,
 					    "TX weight set isn't supported for the leafs");
 			return false;
 		}
+		if (attrs[DEVLINK_ATTR_RATE_TC_BWS] && !ops->rate_leaf_tc_bw_set) {
+			NL_SET_ERR_MSG_ATTR(info->extack,
+					    attrs[DEVLINK_ATTR_RATE_TC_BWS],
+					    "TC bandwidth set isn't supported for the leafs");
+			return false;
+		}
 	} else if (type == DEVLINK_RATE_TYPE_NODE) {
 		if (attrs[DEVLINK_ATTR_RATE_TX_SHARE] && !ops->rate_node_tx_share_set) {
 			NL_SET_ERR_MSG(info->extack, "TX share set isn't supported for the nodes");
@@ -449,6 +570,12 @@ static bool devlink_rate_set_ops_supported(const struct devlink_ops *ops,
 					    "TX weight set isn't supported for the nodes");
 			return false;
 		}
+		if (attrs[DEVLINK_ATTR_RATE_TC_BWS] && !ops->rate_node_tc_bw_set) {
+			NL_SET_ERR_MSG_ATTR(info->extack,
+					    attrs[DEVLINK_ATTR_RATE_TC_BWS],
+					    "TC bandwidth set isn't supported for the nodes");
+			return false;
+		}
 	} else {
 		WARN(1, "Unknown type of rate object");
 		return false;
-- 
2.31.1