[RFC][PATCH 1/4] PM: Use a different list of devices for each stage of device suspend

Rafael J. Wysocki
2010-12-13T00:33:42Z

From: Rafael J. Wysocki <rjw@sisk.pl>

Instead of keeping all devices in the same list during system suspend
and resume, regardless of what suspend-resume callbacks have been
executed for them already, use separate lists of devices that have
had their ->prepare(), ->suspend() and ->suspend_noirq() callbacks
executed. This will allow us to simplify the core device suspend and
resume routines.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/base/power/main.c | 53 ++++++++++++++++------------------------------
1 file changed, 19 insertions(+), 34 deletions(-)

Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -42,6 +42,9 @@
*/

LIST_HEAD(dpm_list);
+LIST_HEAD(dpm_prepared_list);
+LIST_HEAD(dpm_suspended_list);
+LIST_HEAD(dpm_noirq_list);

static DEFINE_MUTEX(dpm_list_mtx);
static pm_message_t pm_transition;
@@ -476,14 +479,12 @@ End:
*/
void dpm_resume_noirq(pm_message_t state)
{
- struct list_head list;
ktime_t starttime = ktime_get();

- INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
transition_started = false;
- while (!list_empty(&dpm_list)) {
- struct device *dev = to_device(dpm_list.next);
+ while (!list_empty(&dpm_noirq_list)) {
+ struct device *dev = to_device(dpm_noirq_list.next);

get_device(dev);
if (dev->power.status > DPM_OFF) {
@@ -499,10 +500,9 @@ void dpm_resume_noirq(pm_message_t state
pm_dev_err(dev, state, " early", error);
}
if (!list_empty(&dev->power.entry))
- list_move_tail(&dev->power.entry, &list);
+ list_move_tail(&dev->power.entry, &dpm_suspended_list);
put_device(dev);
}
- list_splice(&list, &dpm_list);
mutex_unlock(&dpm_list_mtx);
dpm_show_time(starttime, state, "early");
resume_device_irqs();
@@ -611,16 +611,14 @@ static bool is_async(struct device *dev)
*/
static void dpm_resume(pm_message_t state)
{
- struct list_head list;
struct device *dev;
ktime_t starttime = ktime_get();

- INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
pm_transition = state;
async_error = 0;

- list_for_each_entry(dev, &dpm_list, power.entry) {
+ list_for_each_entry(dev, &dpm_suspended_list, power.entry) {
if (dev->power.status < DPM_OFF)
continue;

@@ -631,8 +629,8 @@ static void dpm_resume(pm_message_t stat
}
}

- while (!list_empty(&dpm_list)) {
- dev = to_device(dpm_list.next);
+ while (!list_empty(&dpm_suspended_list)) {
+ dev = to_device(dpm_suspended_list.next);
get_device(dev);
if (dev->power.status >= DPM_OFF && !is_async(dev)) {
int error;
@@ -644,15 +642,11 @@ static void dpm_resume(pm_message_t stat
mutex_lock(&dpm_list_mtx);
if (error)
pm_dev_err(dev, state, "", error);
- } else if (dev->power.status == DPM_SUSPENDING) {
- /* Allow new children of the device to be registered */
- dev->power.status = DPM_RESUMING;
}
if (!list_empty(&dev->power.entry))
- list_move_tail(&dev->power.entry, &list);
+ list_move_tail(&dev->power.entry, &dpm_prepared_list);
put_device(dev);
}
- list_splice(&list, &dpm_list);
mutex_unlock(&dpm_list_mtx);
async_synchronize_full();
dpm_show_time(starttime, state, NULL);
@@ -699,8 +693,8 @@ static void dpm_complete(pm_message_t st
INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
transition_started = false;
- while (!list_empty(&dpm_list)) {
- struct device *dev = to_device(dpm_list.prev);
+ while (!list_empty(&dpm_prepared_list)) {
+ struct device *dev = to_device(dpm_prepared_list.prev);

get_device(dev);
if (dev->power.status > DPM_ON) {
@@ -803,15 +797,13 @@ End:
*/
int dpm_suspend_noirq(pm_message_t state)
{
- struct list_head list;
ktime_t starttime = ktime_get();
int error = 0;

- INIT_LIST_HEAD(&list);
suspend_device_irqs();
mutex_lock(&dpm_list_mtx);
- while (!list_empty(&dpm_list)) {
- struct device *dev = to_device(dpm_list.prev);
+ while (!list_empty(&dpm_suspended_list)) {
+ struct device *dev = to_device(dpm_suspended_list.prev);

get_device(dev);
mutex_unlock(&dpm_list_mtx);
@@ -826,10 +818,9 @@ int dpm_suspend_noirq(pm_message_t state
}
dev->power.status = DPM_OFF_IRQ;
if (!list_empty(&dev->power.entry))
- list_move(&dev->power.entry, &list);
+ list_move(&dev->power.entry, &dpm_noirq_list);
put_device(dev);
}
- list_splice_tail(&list, &dpm_list);
mutex_unlock(&dpm_list_mtx);
if (error)
dpm_resume_noirq(resume_event(state));
@@ -957,16 +948,14 @@ static int device_suspend(struct device
*/
static int dpm_suspend(pm_message_t state)
{
- struct list_head list;
ktime_t starttime = ktime_get();
int error = 0;

- INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
pm_transition = state;
async_error = 0;
- while (!list_empty(&dpm_list)) {
- struct device *dev = to_device(dpm_list.prev);
+ while (!list_empty(&dpm_prepared_list)) {
+ struct device *dev = to_device(dpm_prepared_list.prev);

get_device(dev);
mutex_unlock(&dpm_list_mtx);
@@ -980,12 +969,11 @@ static int dpm_suspend(pm_message_t stat
break;
}
if (!list_empty(&dev->power.entry))
- list_move(&dev->power.entry, &list);
+ list_move(&dev->power.entry, &dpm_suspended_list);
put_device(dev);
if (async_error)
break;
}
- list_splice(&list, dpm_list.prev);
mutex_unlock(&dpm_list_mtx);
async_synchronize_full();
if (!error)
@@ -1044,10 +1032,8 @@ static int device_prepare(struct device
*/
static int dpm_prepare(pm_message_t state)
{
- struct list_head list;
int error = 0;

- INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
transition_started = true;
while (!list_empty(&dpm_list)) {
@@ -1084,10 +1070,9 @@ static int dpm_prepare(pm_message_t stat
}
dev->power.status = DPM_SUSPENDING;
if (!list_empty(&dev->power.entry))
- list_move_tail(&dev->power.entry, &list);
+ list_move_tail(&dev->power.entry, &dpm_prepared_list);
put_device(dev);
}
- list_splice(&list, &dpm_list);
mutex_unlock(&dpm_list_mtx);
return error;
}