Re: [PATCH net-next 3/7] net/mlx5: Improve QoS error messages with actual depth values

[kernel test robot <lkp@intel.com>]

Hi Tariq,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 312e6f7676e63bbb9b81e5c68e580a9f776cc6f0]

url:    https://github.com/intel-lab-lkp/linux/commits/Tariq-Toukan/net-mlx5-HWS-Generalize-complex-matchers/20250922-170716
base:   312e6f7676e63bbb9b81e5c68e580a9f776cc6f0
patch link:    https://lore.kernel.org/r/1758531671-819655-4-git-send-email-tariqt%40nvidia.com
patch subject: [PATCH net-next 3/7] net/mlx5: Improve QoS error messages with actual depth values
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20250923/202509230959.thBtcZnc-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250923/202509230959.thBtcZnc-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509230959.thBtcZnc-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c:974:4: warning: 'snprintf' will always be truncated; specified size is 80, but format string expands to at least 82 [-Wformat-truncation]
     974 |                         NL_SET_ERR_MSG_FMT_MOD(extack,
         |                         ^
   include/linux/netlink.h:131:2: note: expanded from macro 'NL_SET_ERR_MSG_FMT_MOD'
     131 |         NL_SET_ERR_MSG_FMT((extack), KBUILD_MODNAME ": " fmt, ##args)
         |         ^
   include/linux/netlink.h:116:6: note: expanded from macro 'NL_SET_ERR_MSG_FMT'
     116 |         if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN,               \
         |             ^
   drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c:1448:3: warning: 'snprintf' will always be truncated; specified size is 80, but format string expands to at least 82 [-Wformat-truncation]
    1448 |                 NL_SET_ERR_MSG_FMT_MOD(extack,
         |                 ^
   include/linux/netlink.h:131:2: note: expanded from macro 'NL_SET_ERR_MSG_FMT_MOD'
     131 |         NL_SET_ERR_MSG_FMT((extack), KBUILD_MODNAME ": " fmt, ##args)
         |         ^
   include/linux/netlink.h:116:6: note: expanded from macro 'NL_SET_ERR_MSG_FMT'
     116 |         if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN,               \
         |             ^
   2 warnings generated.


vim +/snprintf +974 drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c

   955	
   956	static int
   957	esw_qos_vport_tc_enable(struct mlx5_vport *vport, enum sched_node_type type,
   958				struct netlink_ext_ack *extack)
   959	{
   960		struct mlx5_esw_sched_node *vport_node = vport->qos.sched_node;
   961		struct mlx5_esw_sched_node *parent = vport_node->parent;
   962		int err;
   963	
   964		if (type == SCHED_NODE_TYPE_TC_ARBITER_TSAR) {
   965			int new_level, max_level;
   966	
   967			/* Increase the parent's level by 2 to account for both the
   968			 * TC arbiter and the vports TC scheduling element.
   969			 */
   970			new_level = (parent ? parent->level : 2) + 2;
   971			max_level = 1 << MLX5_CAP_QOS(vport_node->esw->dev,
   972						      log_esw_max_sched_depth);
   973			if (new_level > max_level) {
 > 974				NL_SET_ERR_MSG_FMT_MOD(extack,
   975						       "TC arbitration on leafs is not supported beyond max scheduling depth %d",
   976						       max_level);
   977				return -EOPNOTSUPP;
   978			}
   979		}
   980	
   981		esw_assert_qos_lock_held(vport->dev->priv.eswitch);
   982	
   983		if (type == SCHED_NODE_TYPE_RATE_LIMITER)
   984			err = esw_qos_create_rate_limit_element(vport_node, extack);
   985		else
   986			err = esw_qos_tc_arbiter_scheduling_setup(vport_node, extack);
   987		if (err)
   988			return err;
   989	
   990		/* Rate limiters impact multiple nodes not directly connected to them
   991		 * and are not direct members of the QoS hierarchy.
   992		 * Unlink it from the parent to reflect that.
   993		 */
   994		if (type == SCHED_NODE_TYPE_RATE_LIMITER) {
   995			list_del_init(&vport_node->entry);
   996			vport_node->level = 0;
   997		}
   998	
   999		err  = esw_qos_create_vport_tc_sched_elements(vport, type, extack);
  1000		if (err)
  1001			goto err_sched_nodes;
  1002	
  1003		return 0;
  1004	
  1005	err_sched_nodes:
  1006		if (type == SCHED_NODE_TYPE_RATE_LIMITER) {
  1007			esw_qos_node_destroy_sched_element(vport_node, NULL);
  1008			esw_qos_node_attach_to_parent(vport_node);
  1009		} else {
  1010			esw_qos_tc_arbiter_scheduling_teardown(vport_node, NULL);
  1011		}
  1012		return err;
  1013	}
  1014	

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