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

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
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_RUNTIME) += runtime.o
obj-$(CONFIG_PM_TRACE_RTC) += trace.o
......
......@@ -140,12 +140,8 @@ void pm_clk_remove(struct device *dev, const char *con_id)
void pm_clk_init(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
if (!psd)
return;
INIT_LIST_HEAD(&psd->clock_list);
spin_lock_init(&psd->lock);
if (psd)
INIT_LIST_HEAD(&psd->clock_list);
}
/**
......@@ -157,16 +153,8 @@ void pm_clk_init(struct device *dev)
*/
int pm_clk_create(struct device *dev)
{
struct pm_subsys_data *psd;
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;
int ret = dev_pm_get_subsys_data(dev);
return ret < 0 ? ret : 0;
}
/**
......@@ -185,8 +173,6 @@ void pm_clk_destroy(struct device *dev)
if (!psd)
return;
dev->power.subsys_data = NULL;
spin_lock_irq(&psd->lock);
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);
kfree(psd);
dev_pm_put_subsys_data(dev);
}
#endif /* CONFIG_PM */
......
/*
* 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);
......@@ -423,6 +423,7 @@ struct wakeup_source;
struct pm_subsys_data {
spinlock_t lock;
unsigned int refcount;
#ifdef CONFIG_PM_CLK
struct list_head clock_list;
#endif
......@@ -473,6 +474,8 @@ struct dev_pm_info {
};
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,
......
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