linux-kernel - Re: [PATCH 3/4][RFC v2] PM / hibernate: introduce a flag to indicate resuming from hibernation

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Date:	Sat, 25 Jun 2016 18:53:02 +0200
From:	Pavel Machek <pavel@....cz>
To:	Chen Yu <yu.c.chen@...el.com>
Cc:	linux-pm@...r.kernel.org, x86@...nel.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	"H. Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...e.de>,
	Brian Gerst <brgerst@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	Varun Koyyalagunta <cpudebug@...ttech.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4][RFC v2] PM / hibernate: introduce a flag to indicate
 resuming from hibernation

On Sun 2016-06-26 00:18:52, Chen Yu wrote:
> Sometime we need to do some operations before resuming from
> hibernation, so introduce a flag to indicate this stage.
> 
> Signed-off-by: Chen Yu <yu.c.chen@...el.com>
> ---
>  include/linux/suspend.h  | 7 +++++++
>  kernel/power/hibernate.c | 3 +++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> index 8b6ec7e..422e87a 100644
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -384,6 +384,12 @@ extern bool system_entering_hibernation(void);
>  extern bool hibernation_available(void);
>  asmlinkage int swsusp_save(void);
>  extern struct pbe *restore_pblist;
> +extern bool in_resume_hibernate;

in_resume_hibernation? But it is pretty sad if we need another such
state function...
								Pavel

> +static inline bool hibernation_in_resume(void)
> +{
> +	return in_resume_hibernate;
> +}
>  #else /* CONFIG_HIBERNATION */
>  static inline void register_nosave_region(unsigned long b, unsigned long e) {}
>  static inline void register_nosave_region_late(unsigned long b, unsigned long e) {}
> @@ -395,6 +401,7 @@ static inline void hibernation_set_ops(const struct platform_hibernation_ops *op
>  static inline int hibernate(void) { return -ENOSYS; }
>  static inline bool system_entering_hibernation(void) { return false; }
>  static inline bool hibernation_available(void) { return false; }
> +static inline bool hibernation_in_resume(void) { return false; }
>  #endif /* CONFIG_HIBERNATION */
>  
>  /* Hibernation and suspend events */
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index fca9254..41be909 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -43,6 +43,7 @@ static char resume_file[256] = CONFIG_PM_STD_PARTITION;
>  dev_t swsusp_resume_device;
>  sector_t swsusp_resume_block;
>  __visible int in_suspend __nosavedata;
> +bool in_resume_hibernate;
>  
>  enum {
>  	HIBERNATION_INVALID,
> @@ -433,6 +434,7 @@ static int resume_target_kernel(bool platform_mode)
>  	if (error)
>  		goto Cleanup;
>  
> +	in_resume_hibernate = true;
>  	error = disable_nonboot_cpus();
>  	if (error)
>  		goto Enable_cpus;
> @@ -474,6 +476,7 @@ static int resume_target_kernel(bool platform_mode)
>  	local_irq_enable();
>  
>   Enable_cpus:
> +	in_resume_hibernate = false;
>  	enable_nonboot_cpus();
>  
>   Cleanup:

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html