devlink: Implement devlink param multi attribute nested data values

Devlink param value attribute is not defined since devlink is handling
the value validating and parsing internally, this allows us to implement
multi attribute values without breaking any policies.

Devlink param multi-attribute values are considered to be dynamically
sized arrays of u64 values, by introducing a new devlink param type
DEVLINK_PARAM_TYPE_U64_ARRAY, driver and user space can set a variable
count of u64 values into the DEVLINK_ATTR_PARAM_VALUE_DATA attribute.

Implement get/set parsing and add to the internal value structure passed
to drivers.

This is useful for devices that need to configure a list of values for
a specific configuration.

example:
$ devlink dev param show pci/... name multi-value-param
name multi-value-param type driver-specific
values:
cmode permanent value: 0,1,2,3,4,5,6,7

$ devlink dev param set pci/... name multi-value-param \
		value 4,5,6,7,0,1,2,3 cmode permanent

Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Link: https://patch.msgid.link/20260609040453.711932-5-rkannoth@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml
index 247b147d689fa707856abf7e7d5afdda1981d942..52ad1e7805d198424780c5088c7460490b535f1e 100644 (file)
--- a/Documentation/netlink/specs/devlink.yaml
+++ b/Documentation/netlink/specs/devlink.yaml
@@ -234,6 +234,10 @@ definitions:
         value: 10
       -
         name: binary
+      -
+        name: u64-array
+        value: 129
+
   -
     name: rate-tc-index-max
     type: const

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 5f4083dc4345e9dc682cf01f471851e3d6edf9a7..dd546dbd57cf0a74a79fba8cdd3819d116a3392e 100644 (file)
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -433,6 +433,13 @@ enum devlink_param_type {
        DEVLINK_PARAM_TYPE_U64 = DEVLINK_VAR_ATTR_TYPE_U64,
        DEVLINK_PARAM_TYPE_STRING = DEVLINK_VAR_ATTR_TYPE_STRING,
        DEVLINK_PARAM_TYPE_BOOL = DEVLINK_VAR_ATTR_TYPE_FLAG,
+       DEVLINK_PARAM_TYPE_U64_ARRAY = DEVLINK_VAR_ATTR_TYPE_U64_ARRAY,
+};
+
+#define __DEVLINK_PARAM_MAX_ARRAY_SIZE 32
+struct devlink_param_u64_array {
+       u64 size;
+       u64 val[__DEVLINK_PARAM_MAX_ARRAY_SIZE];
 };
 
 union devlink_param_value {
@@ -442,6 +449,7 @@ union devlink_param_value {
        u64 vu64;
        char vstr[__DEVLINK_PARAM_MAX_STRING_VALUE];
        bool vbool;
+       struct devlink_param_u64_array u64arr;
 };
 
 struct devlink_param_gset_ctx {

diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 0b165eac7619befc907c28156f434379eb671fd7..ca713bcc47b9d184a40bc9a34e9f871a4b149fe2 100644 (file)
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -406,6 +406,7 @@ enum devlink_var_attr_type {
        DEVLINK_VAR_ATTR_TYPE_BINARY,
        __DEVLINK_VAR_ATTR_TYPE_CUSTOM_BASE = 0x80,
        /* Any possible custom types, unrelated to NLA_* values go below */
+       DEVLINK_VAR_ATTR_TYPE_U64_ARRAY,
 };
 
 enum devlink_attr {

diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
index 81899786fd980492873cedfb17b05a2faed63ded..f52b0c2b19ed63fae14b77a0816adef872c3a7c1 100644 (file)
--- a/net/devlink/netlink_gen.c
+++ b/net/devlink/netlink_gen.c
@@ -37,6 +37,8 @@ devlink_attr_param_type_validate(const struct nlattr *attr,
        case DEVLINK_VAR_ATTR_TYPE_NUL_STRING:
                fallthrough;
        case DEVLINK_VAR_ATTR_TYPE_BINARY:
+               fallthrough;
+       case DEVLINK_VAR_ATTR_TYPE_U64_ARRAY:
                return 0;
        }
        NL_SET_ERR_MSG_ATTR(extack, attr, "invalid enum value");

diff --git a/net/devlink/param.c b/net/devlink/param.c
index bd3881349c6049af97367722080928aae5686e0d..3e9d2e5750c235f4aaef11bf83bc682535326e93 100644 (file)
--- a/net/devlink/param.c
+++ b/net/devlink/param.c
@@ -252,6 +252,15 @@ devlink_nl_param_value_put(struct sk_buff *msg, enum devlink_param_type type,
                                return -EMSGSIZE;
                }
                break;
+       case DEVLINK_PARAM_TYPE_U64_ARRAY:
+               if (val->u64arr.size > __DEVLINK_PARAM_MAX_ARRAY_SIZE)
+                       return -EMSGSIZE;
+
+               for (int i = 0; i < val->u64arr.size; i++) {
+                       if (nla_put_uint(msg, nla_type, val->u64arr.val[i]))
+                               return -EMSGSIZE;
+               }
+               break;
        }
        return 0;
 }
@@ -537,7 +546,7 @@ devlink_param_value_get_from_info(const struct devlink_param *param,
                                  union devlink_param_value *value)
 {
        struct nlattr *param_data;
-       int len;
+       int len, cnt, rem;
 
        param_data = info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA];
 
@@ -577,6 +586,28 @@ devlink_param_value_get_from_info(const struct devlink_param *param,
                        return -EINVAL;
                value->vbool = nla_get_flag(param_data);
                break;
+
+       case DEVLINK_PARAM_TYPE_U64_ARRAY:
+               cnt = 0;
+               nla_for_each_attr_type(param_data,
+                                      DEVLINK_ATTR_PARAM_VALUE_DATA,
+                                      genlmsg_data(info->genlhdr),
+                                      genlmsg_len(info->genlhdr), rem) {
+                       if (cnt >= __DEVLINK_PARAM_MAX_ARRAY_SIZE)
+                               return -EMSGSIZE;
+
+                       if ((nla_len(param_data) != sizeof(u64)) &&
+                           (nla_len(param_data) != sizeof(u32))) {
+                               NL_SET_BAD_ATTR(info->extack, param_data);
+                               return -EINVAL;
+                       }
+
+                       value->u64arr.val[cnt] = nla_get_uint(param_data);
+                       cnt++;
+               }
+
+               value->u64arr.size = cnt;
+               break;
        }
        return 0;
 }