On Sun, Nov 29, 2015 at 12:49 PM, Jiri Pirko [off-list ref] wrote:

Sun, Nov 29, 2015 at 10:04:07AM CET, gerlitz.or@gmail.com wrote:

quoted

[..]

quoted

+enum mlxsw_hwmon_attr_type {
+       MLXSW_HWMON_ATTR_TYPE_TEMP,
+       MLXSW_HWMON_ATTR_TYPE_TEMP_MAX,
+};
+
+static void mlxsw_hwmon_attr_add(struct mlxsw_hwmon *mlxsw_hwmon,
+                                enum mlxsw_hwmon_attr_type attr_type,
+                                unsigned int type_index, unsigned int num) {
+       struct mlxsw_hwmon_attr *mlxsw_hwmon_attr;
+       unsigned int attr_index;
+
+       attr_index = mlxsw_hwmon->attrs_count;
+       mlxsw_hwmon_attr = &mlxsw_hwmon->hwmon_attrs[attr_index];
+
+       switch (attr_type) {
+       case MLXSW_HWMON_ATTR_TYPE_TEMP:
+               mlxsw_hwmon_attr->dev_attr.show = mlxsw_hwmon_temp_show;
+               mlxsw_hwmon_attr->dev_attr.attr.mode = S_IRUGO;
+               snprintf(mlxsw_hwmon_attr->name, sizeof(mlxsw_hwmon_attr->name),
+                        "temp%u_input", num + 1);
+               break;
+       case MLXSW_HWMON_ATTR_TYPE_TEMP_MAX:
+               mlxsw_hwmon_attr->dev_attr.show = mlxsw_hwmon_temp_max_show;
+               mlxsw_hwmon_attr->dev_attr.attr.mode = S_IRUGO;
+               snprintf(mlxsw_hwmon_attr->name, sizeof(mlxsw_hwmon_attr->name),
+                        "temp%u_highest", num + 1);
+               break;
+       default:
+               BUG();

Guys, do we really have to crash the whole system just b/c somehow an
unknown value propagated here during **init** time?

I don't think so.

"default" case simply *cannot* happen. If it happens, it is a stack
corruption or some other fatal problem. I believe that BUG is
appropriate at these cases.

Jiri, as Dave commented today on the LAG series,  BUG_ON() is bad and
is only to ever be used when the kernel's continued operation is
absolutely impossible, can we change here to WARN_ON() or a like?

Or.

quoted

quoted

+
+       mlxsw_hwmon_attr->type_index = type_index;
+       mlxsw_hwmon_attr->hwmon = mlxsw_hwmon;
+       mlxsw_hwmon_attr->dev_attr.attr.name = mlxsw_hwmon_attr->name;
+       sysfs_attr_init(&mlxsw_hwmon_attr->dev_attr.attr);
+
+       mlxsw_hwmon->attrs[attr_index] = &mlxsw_hwmon_attr->dev_attr.attr;
+       mlxsw_hwmon->attrs_count++;
+}
+

[...]

quoted

+int mlxsw_hwmon_init(struct mlxsw_core *mlxsw_core,
+                    const struct mlxsw_bus_info *mlxsw_bus_info,
+                    struct mlxsw_hwmon **p_hwmon)
+{
+       struct mlxsw_hwmon *mlxsw_hwmon;
+       struct device *hwmon_dev;
+       int err;
+
+       mlxsw_hwmon = kzalloc(sizeof(*mlxsw_hwmon), GFP_KERNEL);
+       if (!mlxsw_hwmon)
+               return -ENOMEM;
+       mlxsw_hwmon->core = mlxsw_core;
+       mlxsw_hwmon->bus_info = mlxsw_bus_info;
+
+       err = mlxsw_hwmon_temp_init(mlxsw_hwmon);
+       if (err)
+               goto err_temp_init;
+
+       mlxsw_hwmon->groups[0] = &mlxsw_hwmon->group;
+       mlxsw_hwmon->group.attrs = mlxsw_hwmon->attrs;
+
+       hwmon_dev = devm_hwmon_device_register_with_groups(mlxsw_bus_info->dev,
+                                                          "mlxsw",
+                                                          mlxsw_hwmon,
+                                                          mlxsw_hwmon->groups);
+       if (IS_ERR(hwmon_dev)) {
+               err = PTR_ERR(hwmon_dev);
+               goto err_hwmon_register;
+       }
+
+       mlxsw_hwmon->hwmon_dev = hwmon_dev;
+       *p_hwmon = mlxsw_hwmon;
+       return 0;
+
+err_hwmon_register:
+err_temp_init:
+       kfree(mlxsw_hwmon);
+       return err;
+}
+