Commit 7a8d37a3 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Greg Kroah-Hartman
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PM: Do not acquire device semaphores upfront during suspend

Remove the code that acquires all device semaphores from the suspend
code path as it causes multiple problems to appear (most notably,
http://bugzilla.kernel.org/show_bug.cgi?id=10030) and revert the
change introduced by commit 4145ed6d
depending on the code being removed.

Remove pm_sleep_lock()/pm_sleep_unlock() from device_add() to avoid
the issue reported at http://bugzilla.kernel.org/show_bug.cgi?id=9874.

It should fix the regreesions reported at:
	http://bugzilla.kernel.org/show_bug.cgi?id=9874
	http://bugzilla.kernel.org/show_bug.cgi?id=10030

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent a4573c48
......@@ -770,13 +770,6 @@ int device_add(struct device *dev)
struct class_interface *class_intf;
int error;
error = pm_sleep_lock();
if (error) {
dev_warn(dev, "Suspicious %s during suspend\n", __FUNCTION__);
dump_stack();
return error;
}
dev = get_device(dev);
if (!dev || !strlen(dev->bus_id)) {
error = -EINVAL;
......@@ -843,7 +836,6 @@ int device_add(struct device *dev)
}
Done:
put_device(dev);
pm_sleep_unlock();
return error;
BusError:
device_pm_remove(dev);
......
......@@ -48,7 +48,6 @@
*/
LIST_HEAD(dpm_active);
static LIST_HEAD(dpm_locked);
static LIST_HEAD(dpm_off);
static LIST_HEAD(dpm_off_irq);
static LIST_HEAD(dpm_destroy);
......@@ -81,28 +80,6 @@ void device_pm_add(struct device *dev)
*/
void device_pm_remove(struct device *dev)
{
/*
* If this function is called during a suspend, it will be blocked,
* because we're holding the device's semaphore at that time, which may
* lead to a deadlock. In that case we want to print a warning.
* However, it may also be called by unregister_dropped_devices() with
* the device's semaphore released, in which case the warning should
* not be printed.
*/
if (down_trylock(&dev->sem)) {
if (down_read_trylock(&pm_sleep_rwsem)) {
/* No suspend in progress, wait on dev->sem */
down(&dev->sem);
up_read(&pm_sleep_rwsem);
} else {
/* Suspend in progress, we may deadlock */
dev_warn(dev, "Suspicious %s during suspend\n",
__FUNCTION__);
dump_stack();
/* The user has been warned ... */
down(&dev->sem);
}
}
pr_debug("PM: Removing info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
......@@ -110,7 +87,6 @@ void device_pm_remove(struct device *dev)
dpm_sysfs_remove(dev);
list_del_init(&dev->power.entry);
mutex_unlock(&dpm_list_mtx);
up(&dev->sem);
}
/**
......@@ -230,6 +206,8 @@ static int resume_device(struct device *dev)
TRACE_DEVICE(dev);
TRACE_RESUME(0);
down(&dev->sem);
if (dev->bus && dev->bus->resume) {
dev_dbg(dev,"resuming\n");
error = dev->bus->resume(dev);
......@@ -245,6 +223,8 @@ static int resume_device(struct device *dev)
error = dev->class->resume(dev);
}
up(&dev->sem);
TRACE_RESUME(error);
return error;
}
......@@ -266,7 +246,7 @@ static void dpm_resume(void)
struct list_head *entry = dpm_off.next;
struct device *dev = to_device(entry);
list_move_tail(entry, &dpm_locked);
list_move_tail(entry, &dpm_active);
mutex_unlock(&dpm_list_mtx);
resume_device(dev);
mutex_lock(&dpm_list_mtx);
......@@ -274,25 +254,6 @@ static void dpm_resume(void)
mutex_unlock(&dpm_list_mtx);
}
/**
* unlock_all_devices - Release each device's semaphore
*
* Go through the dpm_off list. Put each device on the dpm_active
* list and unlock it.
*/
static void unlock_all_devices(void)
{
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_locked)) {
struct list_head *entry = dpm_locked.prev;
struct device *dev = to_device(entry);
list_move(entry, &dpm_active);
up(&dev->sem);
}
mutex_unlock(&dpm_list_mtx);
}
/**
* unregister_dropped_devices - Unregister devices scheduled for removal
*
......@@ -305,7 +266,6 @@ static void unregister_dropped_devices(void)
struct list_head *entry = dpm_destroy.next;
struct device *dev = to_device(entry);
up(&dev->sem);
mutex_unlock(&dpm_list_mtx);
/* This also removes the device from the list */
device_unregister(dev);
......@@ -324,7 +284,6 @@ void device_resume(void)
{
might_sleep();
dpm_resume();
unlock_all_devices();
unregister_dropped_devices();
up_write(&pm_sleep_rwsem);
}
......@@ -388,18 +347,15 @@ int device_power_down(pm_message_t state)
struct list_head *entry = dpm_off.prev;
struct device *dev = to_device(entry);
list_del_init(&dev->power.entry);
error = suspend_device_late(dev, state);
if (error) {
printk(KERN_ERR "Could not power down device %s: "
"error %d\n",
kobject_name(&dev->kobj), error);
if (list_empty(&dev->power.entry))
list_add(&dev->power.entry, &dpm_off);
break;
}
if (list_empty(&dev->power.entry))
list_add(&dev->power.entry, &dpm_off_irq);
if (!list_empty(&dev->power.entry))
list_move(&dev->power.entry, &dpm_off_irq);
}
if (!error)
......@@ -419,6 +375,8 @@ static int suspend_device(struct device *dev, pm_message_t state)
{
int error = 0;
down(&dev->sem);
if (dev->power.power_state.event) {
dev_dbg(dev, "PM: suspend %d-->%d\n",
dev->power.power_state.event, state.event);
......@@ -441,6 +399,9 @@ static int suspend_device(struct device *dev, pm_message_t state)
error = dev->bus->suspend(dev, state);
suspend_report_result(dev->bus->suspend, error);
}
up(&dev->sem);
return error;
}
......@@ -461,11 +422,10 @@ static int dpm_suspend(pm_message_t state)
int error = 0;
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_locked)) {
struct list_head *entry = dpm_locked.prev;
while (!list_empty(&dpm_active)) {
struct list_head *entry = dpm_active.prev;
struct device *dev = to_device(entry);
list_del_init(&dev->power.entry);
mutex_unlock(&dpm_list_mtx);
error = suspend_device(dev, state);
if (error) {
......@@ -476,50 +436,17 @@ static int dpm_suspend(pm_message_t state)
(error == -EAGAIN ?
" (please convert to suspend_late)" :
""));
mutex_lock(&dpm_list_mtx);
if (list_empty(&dev->power.entry))
list_add(&dev->power.entry, &dpm_locked);
break;
}
mutex_lock(&dpm_list_mtx);
if (list_empty(&dev->power.entry))
list_add(&dev->power.entry, &dpm_off);
if (!list_empty(&dev->power.entry))
list_move(&dev->power.entry, &dpm_off);
}
mutex_unlock(&dpm_list_mtx);
return error;
}
/**
* lock_all_devices - Acquire every device's semaphore
*
* Go through the dpm_active list. Carefully lock each device's
* semaphore and put it in on the dpm_locked list.
*/
static void lock_all_devices(void)
{
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_active)) {
struct list_head *entry = dpm_active.next;
struct device *dev = to_device(entry);
/* Required locking order is dev->sem first,
* then dpm_list_mutex. Hence this awkward code.
*/
get_device(dev);
mutex_unlock(&dpm_list_mtx);
down(&dev->sem);
mutex_lock(&dpm_list_mtx);
if (list_empty(entry))
up(&dev->sem); /* Device was removed */
else
list_move_tail(entry, &dpm_locked);
put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
}
/**
* device_suspend - Save state and stop all devices in system.
* @state: new power management state
......@@ -533,7 +460,6 @@ int device_suspend(pm_message_t state)
might_sleep();
down_write(&pm_sleep_rwsem);
lock_all_devices();
error = dpm_suspend(state);
if (error)
device_resume();
......
......@@ -233,7 +233,7 @@ static int ksuspend_usb_init(void)
* singlethreaded. Its job doesn't justify running on more
* than one CPU.
*/
ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd");
ksuspend_usb_wq = create_freezeable_workqueue("ksuspend_usbd");
if (!ksuspend_usb_wq)
return -ENOMEM;
return 0;
......
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