Re: [PATCH v1 1/4] serial: core: Use string length for SysRq magic sequence

[Dmitry Safonov <0x7f454c46@gmail.com>]

Hi Andy,

On 3/10/20 2:57 PM, Andy Shevchenko wrote:
> On Tue, Mar 10, 2020 at 02:38:48PM +0000, Dmitry Safonov wrote:
>> On 3/10/20 1:20 PM, Andy Shevchenko wrote:
>> [..]> @@ -3209,7 +3209,9 @@ static DECLARE_WORK(sysrq_enable_work,
>> uart_sysrq_on);
>>>   */
>>>  static bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
>>>  {
>>> -	if (ARRAY_SIZE(sysrq_toggle_seq) <= 1)
>>> +	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
>>> +
>>> +	if (!sysrq_toggle_seq_len)
>>>  		return false;
>>
>> Eh, I wanted to avoid the strlen() call in runtime for every time sysrq
>> is pressed. It's not very frequent moment surely, but..
> 
> I really don't like ARRAY_SIZE() against plain strings.
> This will use \0 inclusively and confuse the understanding the code.

I still feel a bit awkward that handler will run strlen() for something
that could be done compile-time, but I won't insist.

Thanks again for looking into warning,
          Dmitry