linux-kernel - Re: [PATCH] leds/trigger/cpu: move from CPU

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Date:	Thu, 21 Jul 2016 08:48:49 +0200
From:	Jacek Anaszewski <j.anaszewski@...sung.com>
To:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:	linux-kernel@...r.kernel.org, mingo@...nel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Richard Purdie <rpurdie@...ys.net>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-leds@...r.kernel.org, rt@...utronix.de
Subject: Re: [PATCH] leds/trigger/cpu: move from CPU_STARTING to ONLINE level

Hi Sebastian,

On 07/20/2016 05:24 PM, Sebastian Andrzej Siewior wrote:
> There is no need the ledtriger to be called *that* early in the hotplug
> process (+ with disabled interrupts). As explained by Jacek Anaszewski [0]
> there is no need for it.
> Therefore this patch moves it to the ONLINE/PREPARE_DOWN level using the
> dynamic registration for the id.
>
> [0] https://lkml.kernel.org/r/578C92BC.2070603@samsung.com
>
> Cc: Jacek Anaszewski <j.anaszewski@...sung.com>
> Cc: Linus Torvalds <torvalds@...ux-foundation.org>
> Cc: Linus Walleij <linus.walleij@...aro.org>
> Cc: Paul Gortmaker <paul.gortmaker@...driver.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Richard Purdie <rpurdie@...ys.net>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: linux-leds@...r.kernel.org
> Cc: rt@...utronix.de
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> ---
>   drivers/leds/trigger/ledtrig-cpu.c | 16 ++++++++--------
>   include/linux/cpuhotplug.h         |  1 -
>   2 files changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/leds/trigger/ledtrig-cpu.c b/drivers/leds/trigger/ledtrig-cpu.c
> index 4a6a182d0a88..22f0634dd3fa 100644
> --- a/drivers/leds/trigger/ledtrig-cpu.c
> +++ b/drivers/leds/trigger/ledtrig-cpu.c
> @@ -92,13 +92,13 @@ static struct syscore_ops ledtrig_cpu_syscore_ops = {
>   	.resume		= ledtrig_cpu_syscore_resume,
>   };
>
> -static int ledtrig_starting_cpu(unsigned int cpu)
> +static int ledtrig_online_cpu(unsigned int cpu)
>   {
>   	ledtrig_cpu(CPU_LED_START);
>   	return 0;
>   }
>
> -static int ledtrig_dying_cpu(unsigned int cpu)
> +static int ledtrig_prepare_down_cpu(unsigned int cpu)
>   {
>   	ledtrig_cpu(CPU_LED_STOP);
>   	return 0;
> @@ -107,6 +107,7 @@ static int ledtrig_dying_cpu(unsigned int cpu)
>   static int __init ledtrig_cpu_init(void)
>   {
>   	int cpu;
> +	int ret;
>
>   	/* Supports up to 9999 cpu cores */
>   	BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);
> @@ -126,12 +127,11 @@ static int __init ledtrig_cpu_init(void)
>
>   	register_syscore_ops(&ledtrig_cpu_syscore_ops);
>
> -	/*
> -	 * FIXME: Why needs this to happen in the interrupt disabled
> -	 * low level bringup phase of a cpu?
> -	 */
> -	cpuhp_setup_state(CPUHP_AP_LEDTRIG_STARTING, "AP_LEDTRIG_STARTING",
> -			  ledtrig_starting_cpu, ledtrig_dying_cpu);
> +	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_LEDTRIG_STARTING",
> +				ledtrig_online_cpu, ledtrig_prepare_down_cpu);
> +	if (ret < 0)
> +		pr_err("CPU hotplug notifier for ledtrig-cpu could not be registered: %d\n",
> +		       ret);
>
>   	pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n");
>
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index 09ef54bcba39..282800b42627 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -65,7 +65,6 @@ enum cpuhp_state {
>   	CPUHP_AP_ARM_CORESIGHT_STARTING,
>   	CPUHP_AP_ARM_CORESIGHT4_STARTING,
>   	CPUHP_AP_ARM64_ISNDEP_STARTING,
> -	CPUHP_AP_LEDTRIG_STARTING,
>   	CPUHP_AP_SMPCFD_DYING,
>   	CPUHP_AP_X86_TBOOT_DYING,
>   	CPUHP_AP_NOTIFY_STARTING,
>

Acked-by: Jacek Anaszewski <j.anaszewski@...sung.com>

-- 
Best regards,
Jacek Anaszewski