From: Carolina Jubran cjubran@nvidia.com

The devlink_nl_rate_tc_bw_parse function uses a large stack array for devlink attributes, which triggers a warning about excessive stack usage:

net/devlink/rate.c: In function 'devlink_nl_rate_tc_bw_parse': net/devlink/rate.c:382:1: error: the frame size of 1648 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

Introduce a separate attribute set specifically for rate TC bandwidth parsing that only contains the two attributes actually used: index and bandwidth. This reduces the stack array from DEVLINK_ATTR_MAX entries to just 2 entries, solving the stack usage issue.

Update devlink selftest to use the new 'index' and 'bw' attribute names consistent with the YAML spec.

Example usage with ynl with the new spec:

./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": [ {"index": 0, "bw": 50}, {"index": 1, "bw": 50}, {"index": 2, "bw": 0}, {"index": 3, "bw": 0}, {"index": 4, "bw": 0}, {"index": 5, "bw": 0}, {"index": 6, "bw": 0}, {"index": 7, "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': [{'bw': 50, 'index': 0}, {'bw': 50, 'index': 1}, {'bw': 0, 'index': 2}, {'bw': 0, 'index': 3}, {'bw': 0, 'index': 4}, {'bw': 0, 'index': 5}, {'bw': 0, 'index': 6}, {'bw': 0, 'index': 7}], 'rate-tx-max': 0, 'rate-tx-priority': 0, 'rate-tx-share': 0, 'rate-tx-weight': 0, 'rate-type': 'leaf'}

Fixes: 566e8f108fc7 ("devlink: Extend devlink rate API with traffic classes bandwidth management") Reported-by: Arnd Bergmann arnd@arndb.de Closes: https://lore.kernel.org/netdev/20250708160652.1810573-1-arnd@kernel.org/ Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202507171943.W7DJcs6Y-lkp@intel.com/ Suggested-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Carolina Jubran cjubran@nvidia.com Tested-by: Carolina Jubran cjubran@nvidia.com Signed-off-by: Tariq Toukan tariqt@nvidia.com --- Documentation/netlink/specs/devlink.yaml | 26 ++++++++----------- include/uapi/linux/devlink.h | 11 ++++++-- net/devlink/netlink_gen.c | 6 ++--- net/devlink/netlink_gen.h | 2 +- net/devlink/rate.c | 20 +++++++------- .../drivers/net/hw/devlink_rate_tc_bw.py | 16 ++++++------ 6 files changed, 42 insertions(+), 39 deletions(-)

diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml index 1c4bb0cbe5f0..bb87111d5e16 100644 --- a/Documentation/netlink/specs/devlink.yaml +++ b/Documentation/netlink/specs/devlink.yaml @@ -853,18 +853,6 @@ attribute-sets: type: nest multi-attr: true nested-attributes: dl-rate-tc-bws - - - name: rate-tc-index - type: u8 - checks: - max: rate-tc-index-max - - - name: rate-tc-bw - type: u32 - doc: | - Specifies the bandwidth share assigned to the Traffic Class. - The bandwidth for the traffic class is determined - in proportion to the sum of the shares of all configured classes. - name: dl-dev-stats subset-of: devlink @@ -1271,12 +1259,20 @@ attribute-sets: type: flag - name: dl-rate-tc-bws - subset-of: devlink + name-prefix: devlink-rate-tc-attr- attributes: - - name: rate-tc-index + name: index + type: u8 + checks: + max: rate-tc-index-max - - name: rate-tc-bw + name: bw + type: u32 + doc: | + Specifies the bandwidth share assigned to the Traffic Class. + The bandwidth for the traffic class is determined + in proportion to the sum of the shares of all configured classes.

operations: enum-model: directional diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h index e72bcc239afd..9fcb25a0f447 100644 --- a/include/uapi/linux/devlink.h +++ b/include/uapi/linux/devlink.h @@ -635,8 +635,6 @@ 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 @@ -647,6 +645,15 @@ enum devlink_attr { DEVLINK_ATTR_MAX = __DEVLINK_ATTR_MAX - 1 };

+enum devlink_rate_tc_attr { + DEVLINK_RATE_TC_ATTR_UNSPEC, + DEVLINK_RATE_TC_ATTR_INDEX, /* u8 */ + DEVLINK_RATE_TC_ATTR_BW, /* u32 */ + + __DEVLINK_RATE_TC_ATTR_MAX, + DEVLINK_RATE_TC_ATTR_MAX = __DEVLINK_RATE_TC_ATTR_MAX - 1 +}; + /* Mapping between internal resource described by the field and system * structure */ diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c index c50436433c18..d97c326a9045 100644 --- a/net/devlink/netlink_gen.c +++ b/net/devlink/netlink_gen.c @@ -45,9 +45,9 @@ 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_MAX(NLA_U8, DEVLINK_RATE_TC_INDEX_MAX), - [DEVLINK_ATTR_RATE_TC_BW] = { .type = NLA_U32, }, +const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_RATE_TC_ATTR_BW + 1] = { + [DEVLINK_RATE_TC_ATTR_INDEX] = NLA_POLICY_MAX(NLA_U8, DEVLINK_RATE_TC_INDEX_MAX), + [DEVLINK_RATE_TC_ATTR_BW] = { .type = NLA_U32, }, };

const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1] = { diff --git a/net/devlink/netlink_gen.h b/net/devlink/netlink_gen.h index fb733b5d4ff1..09cc6f264ccf 100644 --- a/net/devlink/netlink_gen.h +++ b/net/devlink/netlink_gen.h @@ -13,7 +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_rate_tc_bws_nl_policy[DEVLINK_RATE_TC_ATTR_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 d39300a9b3d4..110b3fa8a0b1 100644 --- a/net/devlink/rate.c +++ b/net/devlink/rate.c @@ -90,8 +90,8 @@ static int devlink_rate_put_tc_bws(struct sk_buff *msg, u32 *tc_bw) 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])) + if (nla_put_u8(msg, DEVLINK_RATE_TC_ATTR_INDEX, i) || + nla_put_u32(msg, DEVLINK_RATE_TC_ATTR_BW, tc_bw[i])) goto nla_put_failure;

nla_nest_end(msg, nla_tc_bw); @@ -346,26 +346,26 @@ 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]; + struct nlattr *tb[DEVLINK_RATE_TC_ATTR_MAX + 1]; u8 tc_index; int err;

- err = nla_parse_nested(tb, DEVLINK_ATTR_MAX, parent_nest, + err = nla_parse_nested(tb, DEVLINK_RATE_TC_ATTR_MAX, parent_nest, devlink_dl_rate_tc_bws_nl_policy, extack); if (err) return err;

- if (!tb[DEVLINK_ATTR_RATE_TC_INDEX]) { + if (!tb[DEVLINK_RATE_TC_ATTR_INDEX]) { NL_SET_ERR_ATTR_MISS(extack, parent_nest, - DEVLINK_ATTR_RATE_TC_INDEX); + DEVLINK_RATE_TC_ATTR_INDEX); return -EINVAL; }

- tc_index = nla_get_u8(tb[DEVLINK_ATTR_RATE_TC_INDEX]); + tc_index = nla_get_u8(tb[DEVLINK_RATE_TC_ATTR_INDEX]);

- if (!tb[DEVLINK_ATTR_RATE_TC_BW]) { + if (!tb[DEVLINK_RATE_TC_ATTR_BW]) { NL_SET_ERR_ATTR_MISS(extack, parent_nest, - DEVLINK_ATTR_RATE_TC_BW); + DEVLINK_RATE_TC_ATTR_BW); return -EINVAL; }

@@ -376,7 +376,7 @@ static int devlink_nl_rate_tc_bw_parse(struct nlattr *parent_nest, u32 *tc_bw, return -EINVAL; }

- tc_bw[tc_index] = nla_get_u32(tb[DEVLINK_ATTR_RATE_TC_BW]); + tc_bw[tc_index] = nla_get_u32(tb[DEVLINK_RATE_TC_ATTR_BW]);

return 0; } diff --git a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py index 820d8a03becc..835c357919a8 100755 --- a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py +++ b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py @@ -208,14 +208,14 @@ def setup_devlink_rate(cfg): "port-index": port_index, "rate-tx-max": 125000000, "rate-tc-bws": [ - {"rate-tc-index": 0, "rate-tc-bw": 0}, - {"rate-tc-index": 1, "rate-tc-bw": 0}, - {"rate-tc-index": 2, "rate-tc-bw": 0}, - {"rate-tc-index": 3, "rate-tc-bw": 20}, - {"rate-tc-index": 4, "rate-tc-bw": 80}, - {"rate-tc-index": 5, "rate-tc-bw": 0}, - {"rate-tc-index": 6, "rate-tc-bw": 0}, - {"rate-tc-index": 7, "rate-tc-bw": 0}, + {"index": 0, "bw": 0}, + {"index": 1, "bw": 0}, + {"index": 2, "bw": 0}, + {"index": 3, "bw": 20}, + {"index": 4, "bw": 80}, + {"index": 5, "bw": 0}, + {"index": 6, "bw": 0}, + {"index": 7, "bw": 0}, ] }) except NlError as exc:

base-commit: 3fc894728fb3a0d9282e81247b68c07468fe2985