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

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

Hi Andy,

thanks for the patch,

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..

Could you try

: int sysrq_toggle_seq_len = ARRAY_SIZE(sysrq_toggle_seq);
:
: if (sysrq_toggle_seq_len <= 1)
:     return false;
: /* ... */
: port->sysrq_seq++;
: if (port->sysrq_seq + 1 < sysrq_toggle_seq_len) {

if this will shut the warning instead?
BTW, is this gcc 10 you see the warning with?
I have gcc (GCC) 9.2.0 and I don't see a warning with/without the config
string.

Thanks,
          Dmitry