On 2025/1/11 04:41, Rob Herring wrote:
>> From: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
>>
>> __of_add_property_sysfs() hard codes string "security-" length as 9, but
>> that is not obvious for readers.
>>
>> Improve its readability by using strlen().
> Does the compiler optimize the strlen call away? Maybe, maybe not. If
> not, that's N calls to strlen() where N is the number of properties in
> your DT. That's in the 1000s easily.
>
> Do you really want to go test enough compiler versions we support to
> feel confident this is optimized away. I don't.
i understand your concern about performance.
what about below solution ?
int __of_add_property_sysfs(struct device_node *np, struct property *pp)
{
+#define SECURITY_PREFIX "security-"
int rc;
/* Important: Don't leak passwords */
- bool secure = strncmp(pp->name, "security-", 9) == 0;
+ bool secure = strncmp(pp->name, SECURITY_PREFIX,
sizeof(SECURITY_PREFIX) - 1) == 0;
if (!IS_ENABLED(CONFIG_SYSFS))
return 0;
