[PATCH 06/61] Power Management: use mutexes instead of semaphores

Greg Kroah-Hartman
2007-07-11T23:35:21Z

From: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>

The Power Management code uses semaphores as mutexes. Use the mutex API
instead of the (binary) semaphores.

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/power/main.c | 14 ++++++++------
drivers/base/power/power.h | 4 ++--
drivers/base/power/resume.c | 12 ++++++------
drivers/base/power/runtime.c | 12 ++++++------
drivers/base/power/suspend.c | 14 +++++++-------
5 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 05dc876..7b3cc3c 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -20,14 +20,16 @@
*/

#include <linux/device.h>
+#include <linux/mutex.h>
+
#include "power.h"

LIST_HEAD(dpm_active);
LIST_HEAD(dpm_off);
LIST_HEAD(dpm_off_irq);

-DECLARE_MUTEX(dpm_sem);
-DECLARE_MUTEX(dpm_list_sem);
+DEFINE_MUTEX(dpm_mtx);
+DEFINE_MUTEX(dpm_list_mtx);

int (*platform_enable_wakeup)(struct device *dev, int is_on);

@@ -59,12 +61,12 @@ int device_pm_add(struct device * dev)
pr_debug("PM: Adding info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
- down(&dpm_list_sem);
+ mutex_lock(&dpm_list_mtx);
list_add_tail(&dev->power.entry, &dpm_active);
device_pm_set_parent(dev, dev->parent);
if ((error = dpm_sysfs_add(dev)))
list_del(&dev->power.entry);
- up(&dpm_list_sem);
+ mutex_unlock(&dpm_list_mtx);
return error;
}

@@ -73,11 +75,11 @@ void device_pm_remove(struct device * dev)
pr_debug("PM: Removing info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
- down(&dpm_list_sem);
+ mutex_lock(&dpm_list_mtx);
dpm_sysfs_remove(dev);
put_device(dev->power.pm_parent);
list_del_init(&dev->power.entry);
- up(&dpm_list_sem);
+ mutex_unlock(&dpm_list_mtx);
}

diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index fb3d35a..2760f25 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -14,12 +14,12 @@ extern void device_shutdown(void);
/*
* Used to synchronize global power management operations.
*/
-extern struct semaphore dpm_sem;
+extern struct mutex dpm_mtx;

/*
* Used to serialize changes to the dpm_* lists.
*/
-extern struct semaphore dpm_list_sem;
+extern struct mutex dpm_list_mtx;

/*
* The PM lists.
diff --git a/drivers/base/power/resume.c b/drivers/base/power/resume.c
index a2c6418..f6cfea4 100644
--- a/drivers/base/power/resume.c
+++ b/drivers/base/power/resume.c
@@ -80,7 +80,7 @@ static int resume_device_early(struct device * dev)
*/
void dpm_resume(void)
{
- down(&dpm_list_sem);
+ mutex_lock(&dpm_list_mtx);
while(!list_empty(&dpm_off)) {
struct list_head * entry = dpm_off.next;
struct device * dev = to_device(entry);
@@ -88,13 +88,13 @@ void dpm_resume(void)
get_device(dev);
list_move_tail(entry, &dpm_active);

- up(&dpm_list_sem);
+ mutex_unlock(&dpm_list_mtx);
if (!dev->power.prev_state.event)
resume_device(dev);
- down(&dpm_list_sem);
+ mutex_lock(&dpm_list_mtx);
put_device(dev);
}
- up(&dpm_list_sem);
+ mutex_unlock(&dpm_list_mtx);
}

@@ -108,9 +108,9 @@ void dpm_resume(void)
void device_resume(void)
{
might_sleep();
- down(&dpm_sem);
+ mutex_lock(&dpm_mtx);
dpm_resume();
- up(&dpm_sem);
+ mutex_unlock(&dpm_mtx);
}

EXPORT_SYMBOL_GPL(device_resume);
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 96370ec..df6174d 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -32,9 +32,9 @@ static void runtime_resume(struct device * dev)

void dpm_runtime_resume(struct device * dev)
{
- down(&dpm_sem);
+ mutex_lock(&dpm_mtx);
runtime_resume(dev);
- up(&dpm_sem);
+ mutex_unlock(&dpm_mtx);
}
EXPORT_SYMBOL(dpm_runtime_resume);

@@ -49,7 +49,7 @@ int dpm_runtime_suspend(struct device * dev, pm_message_t state)
{
int error = 0;

- down(&dpm_sem);
+ mutex_lock(&dpm_mtx);
if (dev->power.power_state.event == state.event)
goto Done;

@@ -59,7 +59,7 @@ int dpm_runtime_suspend(struct device * dev, pm_message_t state)
if (!(error = suspend_device(dev, state)))
dev->power.power_state = state;
Done:
- up(&dpm_sem);
+ mutex_unlock(&dpm_mtx);
return error;
}
EXPORT_SYMBOL(dpm_runtime_suspend);
@@ -78,8 +78,8 @@ EXPORT_SYMBOL(dpm_runtime_suspend);
*/
void dpm_set_power_state(struct device * dev, pm_message_t state)
{
- down(&dpm_sem);
+ mutex_lock(&dpm_mtx);
dev->power.power_state = state;
- up(&dpm_sem);
+ mutex_unlock(&dpm_mtx);
}
#endif /* 0 */
diff --git a/drivers/base/power/suspend.c b/drivers/base/power/suspend.c
index 42d2b86..9d6701c 100644
--- a/drivers/base/power/suspend.c
+++ b/drivers/base/power/suspend.c
@@ -108,7 +108,7 @@ int suspend_device(struct device * dev, pm_message_t state)

/*
* This is called with interrupts off, only a single CPU
- * running. We can't do down() on a semaphore (and we don't
+ * running. We can't acquire a mutex or semaphore (and we don't
* need the protection)
*/
static int suspend_device_late(struct device *dev, pm_message_t state)
@@ -153,18 +153,18 @@ int device_suspend(pm_message_t state)
int error = 0;

might_sleep();
- down(&dpm_sem);
- down(&dpm_list_sem);
+ mutex_lock(&dpm_mtx);
+ mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_active) && error == 0) {
struct list_head * entry = dpm_active.prev;
struct device * dev = to_device(entry);

get_device(dev);
- up(&dpm_list_sem);
+ mutex_unlock(&dpm_list_mtx);

error = suspend_device(dev, state);

- down(&dpm_list_sem);
+ mutex_lock(&dpm_list_mtx);

/* Check if the device got removed */
if (!list_empty(&dev->power.entry)) {
@@ -179,11 +179,11 @@ int device_suspend(pm_message_t state)
error == -EAGAIN ? " (please convert to suspend_late)" : "");
put_device(dev);
}
- up(&dpm_list_sem);
+ mutex_unlock(&dpm_list_mtx);
if (error)
dpm_resume();

- up(&dpm_sem);
+ mutex_unlock(&dpm_mtx);
return error;
}

--
1.5.2.2