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Commit ef27bed1 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM: Reference counting of power.subsys_data 



Since the power.subsys_data device field will be used by multiple
filesystems, introduce a reference counting mechanism for it to avoid
freeing it prematurely or changing its value at a wrong time.

Make the PM clocks management code that currently is the only user of
power.subsys_data use the new reference counting.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 5c095a0e

drivers/base/power/Makefile

+1 −1
Original line number Original line Diff line number Diff line 
obj-$(CONFIG_PM)	+= sysfs.o generic_ops.o

obj-$(CONFIG_PM)	+= sysfs.o generic_ops.o common.o

obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o

obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o

obj-$(CONFIG_PM_RUNTIME)	+= runtime.o

obj-$(CONFIG_PM_RUNTIME)	+= runtime.o

obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o

obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o

drivers/base/power/clock_ops.c

+5 −19
Original line number Original line Diff line number Diff line
@@ -140,12 +140,8 @@ void pm_clk_remove(struct device *dev, const char *con_id) 
void pm_clk_init(struct device *dev)

void pm_clk_init(struct device *dev)

{

{

	struct pm_subsys_data *psd = dev_to_psd(dev);

	struct pm_subsys_data *psd = dev_to_psd(dev);



	if (psd)

	if (!psd)

		return;



		INIT_LIST_HEAD(&psd->clock_list);

		INIT_LIST_HEAD(&psd->clock_list);

	spin_lock_init(&psd->lock);

}

}





/**

/**
@@ -157,16 +153,8 @@ void pm_clk_init(struct device *dev) 
 */

 */

int pm_clk_create(struct device *dev)

int pm_clk_create(struct device *dev)

{

{

	struct pm_subsys_data *psd;

	int ret = dev_pm_get_subsys_data(dev);



	return ret < 0 ? ret : 0;

	psd = kzalloc(sizeof(*psd), GFP_KERNEL);

	if (!psd) {

		dev_err(dev, "Not enough memory for PM clock data.\n");

		return -ENOMEM;

	}

	dev->power.subsys_data = psd;

	pm_clk_init(dev);

	return 0;

}

}





/**

/**
@@ -185,8 +173,6 @@ void pm_clk_destroy(struct device *dev) 
	if (!psd)

	if (!psd)

		return;

		return;





	dev->power.subsys_data = NULL;



	spin_lock_irq(&psd->lock);

	spin_lock_irq(&psd->lock);





	list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)

	list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
@@ -194,7 +180,7 @@ void pm_clk_destroy(struct device *dev) 




	spin_unlock_irq(&psd->lock);

	spin_unlock_irq(&psd->lock);





	kfree(psd);

	dev_pm_put_subsys_data(dev);

}

}





#endif /* CONFIG_PM */

#endif /* CONFIG_PM */

drivers/base/power/common.c

0 → 100644
+87 −0
Original line number Original line Diff line number Diff line 
/*

 * drivers/base/power/common.c - Common device power management code.

 *

 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.

 *

 * This file is released under the GPLv2.

 */



#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/device.h>

#include <linux/pm_runtime.h>



/**

 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.

 * @dev: Device to handle.

 *

 * If power.subsys_data is NULL, point it to a new object, otherwise increment

 * its reference counter.  Return 1 if a new object has been created, otherwise

 * return 0 or error code.

 */

int dev_pm_get_subsys_data(struct device *dev)

{

	struct pm_subsys_data *psd;

	int ret = 0;



	psd = kzalloc(sizeof(*psd), GFP_KERNEL);

	if (!psd)

		return -ENOMEM;



	spin_lock_irq(&dev->power.lock);



	if (dev->power.subsys_data) {

		dev->power.subsys_data->refcount++;

	} else {

		spin_lock_init(&psd->lock);

		psd->refcount = 1;

		dev->power.subsys_data = psd;

		pm_clk_init(dev);

		psd = NULL;

		ret = 1;

	}



	spin_unlock_irq(&dev->power.lock);



	/* kfree() verifies that its argument is nonzero. */

	kfree(psd);



	return ret;

}

EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);



/**

 * dev_pm_put_subsys_data - Drop reference to power.subsys_data.

 * @dev: Device to handle.

 *

 * If the reference counter of power.subsys_data is zero after dropping the

 * reference, power.subsys_data is removed.  Return 1 if that happens or 0

 * otherwise.

 */

int dev_pm_put_subsys_data(struct device *dev)

{

	struct pm_subsys_data *psd;

	int ret = 0;



	spin_lock_irq(&dev->power.lock);



	psd = dev_to_psd(dev);

	if (!psd) {

		ret = -EINVAL;

		goto out;

	}



	if (--psd->refcount == 0) {

		dev->power.subsys_data = NULL;

		kfree(psd);

		ret = 1;

	}



 out:

	spin_unlock_irq(&dev->power.lock);



	return ret;

}

EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);

include/linux/pm.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -423,6 +423,7 @@ struct wakeup_source; 




struct pm_subsys_data {

struct pm_subsys_data {

	spinlock_t lock;

	spinlock_t lock;

	unsigned int refcount;

#ifdef CONFIG_PM_CLK

#ifdef CONFIG_PM_CLK

	struct list_head clock_list;

	struct list_head clock_list;

#endif

#endif
@@ -473,6 +474,8 @@ struct dev_pm_info { 
};

};





extern void update_pm_runtime_accounting(struct device *dev);

extern void update_pm_runtime_accounting(struct device *dev);

extern int dev_pm_get_subsys_data(struct device *dev);

extern int dev_pm_put_subsys_data(struct device *dev);





/*

/*

 * Power domains provide callbacks that are executed during system suspend,

 * Power domains provide callbacks that are executed during system suspend,