Re: [PATCH v3 3/3] reboot: refactor and comment the cpu selection code

[Petr Mladek]

On Tue 2020-11-03 22:40:25, Matteo Croce wrote:
> From: Matteo Croce <mcroce@xxxxxxxxxxxxx>
> 
> Small improvements to the code, without changing the way it works:
> - use a local variable, to avoid a small time lapse where reboot_cpu
>   can have an invalid value
> - comment the code which is not easy to understand at a glance
> - merge two identical code blocks into one
> - replace pointer arithmetics with equivalent array syntax
> 
> Signed-off-by: Matteo Croce <mcroce@xxxxxxxxxxxxx>
> ---
>  kernel/reboot.c | 30 +++++++++++++++++-------------
>  1 file changed, 17 insertions(+), 13 deletions(-)
> 
> diff --git a/kernel/reboot.c b/kernel/reboot.c
> index af6f23d8bea1..dd483bde932b 100644
> --- a/kernel/reboot.c
> +++ b/kernel/reboot.c
> @@ -551,20 +551,24 @@ static int __init reboot_setup(char *str)
>  			break;
>  
>  		case 's':
> -			if (isdigit(*(str+1)))
> -				reboot_cpu = simple_strtoul(str+1, NULL, 0);
> -			else if (str[1] == 'm' && str[2] == 'p' &&
> -							isdigit(*(str+3)))
> -				reboot_cpu = simple_strtoul(str+3, NULL, 0);
> -			else
> +			/*
> +			 * reboot_cpu is s[mp]#### with #### being the processor
> +			 * to be used for rebooting. Skip 's' or 'smp' prefix.
> +			 */
> +			str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
> +
> +			if (isdigit(str[0])) {
> +				int cpu = simple_strtoul(str, NULL, 0);
> +
> +				if (cpu >= num_possible_cpus()) {
> +					pr_err("Ignoring the CPU number in reboot= option. "
> +					"CPU %d exceeds possible cpu number %d\n",

Same here. I am not sure if Andrew would like to get this on a single
line.

In both cases:

Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>

Best Regards,
Petr