On Thu, 30 May 2013 15:58:04 +0800 liguang <lig.f...@cn.fujitsu.com> wrote:
> kernel_shutdown_prepare's parameter can be removed
> by checking global 'system_state', so, maybe we
> can save a register to be used :-).
>
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -382,11 +382,10 @@ void kernel_restart(char *cmd)
> }
> EXPORT_SYMBOL_GPL(kernel_restart);
>
> -static void kernel_shutdown_prepare(enum system_states state)
> +static void kernel_shutdown_prepare(void)
> {
> blocking_notifier_call_chain(&reboot_notifier_list,
> - (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
> - system_state = state;
> + (system_state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
> usermodehelper_disable();
> device_shutdown();
> }
> @@ -397,7 +396,7 @@ static void kernel_shutdown_prepare(enum system_states
> state)
> */
> void kernel_halt(void)
> {
> - kernel_shutdown_prepare(SYSTEM_HALT);
> + kernel_shutdown_prepare();
> disable_nonboot_cpus();
> syscore_shutdown();
> printk(KERN_EMERG "System halted.\n");
> @@ -414,7 +413,7 @@ EXPORT_SYMBOL_GPL(kernel_halt);
> */
> void kernel_power_off(void)
> {
> - kernel_shutdown_prepare(SYSTEM_POWER_OFF);
> + kernel_shutdown_prepare();
> if (pm_power_off_prepare)
> pm_power_off_prepare();
> disable_nonboot_cpus();
> @@ -484,11 +483,13 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2,
> unsigned int, cmd,
> break;
>
> case LINUX_REBOOT_CMD_HALT:
> + system_state = SYSTEM_HALT;
> kernel_halt();
> do_exit(0);
> panic("cannot halt");
>
> case LINUX_REBOOT_CMD_POWER_OFF:
> + system_state = SYSTEM_POWER_OFF;
> kernel_power_off();
> do_exit(0);
> break;
No, this changes behavior for all other callers of kernel_halt() and
kernel_power_off(): system_state will no longer be updated for those
callers.
And passing an argument via a global variable is not nice :(
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