Commit 1476bb20 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM: runtime: Convert pm_runtime_blocked() to static inline 



The comment in pm_runtime_blocked() is acutally wrong: power.last_status
is not a bit field.  Its data type is an enum and so one can reasonably
assume that partial updates of it will not be observed.

Accordingly, pm_runtime_blocked() can be converted to a static inline
function and the related locking overhead can be eliminated, so long
as it is only used in system suspend/resume code paths because
power.last_status is not expected to be updated concurrently while
that code is running.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/1923449.tdWV9SEqCh@rjwysocki.net
parent cb88c229

drivers/base/power/runtime.c

+0 −17
Original line number Diff line number Diff line
@@ -1560,23 +1560,6 @@ void pm_runtime_enable(struct device *dev) 
}

EXPORT_SYMBOL_GPL(pm_runtime_enable);



bool pm_runtime_blocked(struct device *dev)

{

	bool ret;



	/*

	 * dev->power.last_status is a bit field, so in case it is updated via

	 * RMW, read it under the spin lock.

	 */

	spin_lock_irq(&dev->power.lock);



	ret = dev->power.last_status == RPM_BLOCKED;



	spin_unlock_irq(&dev->power.lock);



	return ret;

}



static void pm_runtime_disable_action(void *data)

{

	pm_runtime_dont_use_autosuspend(data);

include/linux/pm_runtime.h

+11 −1
Original line number Diff line number Diff line
@@ -82,7 +82,6 @@ extern bool pm_runtime_block_if_disabled(struct device *dev); 
extern void pm_runtime_unblock(struct device *dev);

extern void pm_runtime_enable(struct device *dev);

extern void __pm_runtime_disable(struct device *dev, bool check_resume);

extern bool pm_runtime_blocked(struct device *dev);

extern void pm_runtime_allow(struct device *dev);

extern void pm_runtime_forbid(struct device *dev);

extern void pm_runtime_no_callbacks(struct device *dev);
@@ -200,6 +199,17 @@ static inline bool pm_runtime_enabled(struct device *dev) 
	return !dev->power.disable_depth;

}



/**

 * pm_runtime_blocked - Check if runtime PM enabling is blocked.

 * @dev: Target device.

 *

 * Do not call this function outside system suspend/resume code paths.

 */

static inline bool pm_runtime_blocked(struct device *dev)

{

	return dev->power.last_status == RPM_BLOCKED;

}



/**

 * pm_runtime_has_no_callbacks - Check if runtime PM callbacks may be present.

 * @dev: Target device.