Commit 4bf236a3 authored by Bart Van Assche's avatar Bart Van Assche Committed by Rafael J. Wysocki
Browse files

PM / sleep: Make lock/unlock_system_sleep() available to kernel modules 



Since pm_mutex is not exported using lock/unlock_system_sleep() from
inside a kernel module causes a "pm_mutex undefined" linker error.
Hence move lock/unlock_system_sleep() into kernel/power/main.c and
export these.

Signed-off-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent bdbc98ab

include/linux/suspend.h

+2 −26
Original line number Diff line number Diff line
@@ -443,32 +443,8 @@ extern bool pm_save_wakeup_count(unsigned int count); 
extern void pm_wakep_autosleep_enabled(bool set);

extern void pm_print_active_wakeup_sources(void);



static inline void lock_system_sleep(void)

{

	current->flags |= PF_FREEZER_SKIP;

	mutex_lock(&pm_mutex);

}



static inline void unlock_system_sleep(void)

{

	/*

	 * Don't use freezer_count() because we don't want the call to

	 * try_to_freeze() here.

	 *

	 * Reason:

	 * Fundamentally, we just don't need it, because freezing condition

	 * doesn't come into effect until we release the pm_mutex lock,

	 * since the freezer always works with pm_mutex held.

	 *

	 * More importantly, in the case of hibernation,

	 * unlock_system_sleep() gets called in snapshot_read() and

	 * snapshot_write() when the freezing condition is still in effect.

	 * Which means, if we use try_to_freeze() here, it would make them

	 * enter the refrigerator, thus causing hibernation to lockup.

	 */

	current->flags &= ~PF_FREEZER_SKIP;

	mutex_unlock(&pm_mutex);

}

extern void lock_system_sleep(void);

extern void unlock_system_sleep(void);



#else /* !CONFIG_PM_SLEEP */

kernel/power/main.c

+29 −0
Original line number Diff line number Diff line
@@ -22,6 +22,35 @@ DEFINE_MUTEX(pm_mutex); 


#ifdef CONFIG_PM_SLEEP



void lock_system_sleep(void)

{

	current->flags |= PF_FREEZER_SKIP;

	mutex_lock(&pm_mutex);

}

EXPORT_SYMBOL_GPL(lock_system_sleep);



void unlock_system_sleep(void)

{

	/*

	 * Don't use freezer_count() because we don't want the call to

	 * try_to_freeze() here.

	 *

	 * Reason:

	 * Fundamentally, we just don't need it, because freezing condition

	 * doesn't come into effect until we release the pm_mutex lock,

	 * since the freezer always works with pm_mutex held.

	 *

	 * More importantly, in the case of hibernation,

	 * unlock_system_sleep() gets called in snapshot_read() and

	 * snapshot_write() when the freezing condition is still in effect.

	 * Which means, if we use try_to_freeze() here, it would make them

	 * enter the refrigerator, thus causing hibernation to lockup.

	 */

	current->flags &= ~PF_FREEZER_SKIP;

	mutex_unlock(&pm_mutex);

}

EXPORT_SYMBOL_GPL(unlock_system_sleep);



/* Routines for PM-transition notifications */



static BLOCKING_NOTIFIER_HEAD(pm_chain_head);