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linux-next/include/linux/pm_runtime.h
Rafael J. Wysocki 36003d4cf5 driver core: Fix PM-runtime for links added during consumer probe 
Commit 4c06c4e6cf ("driver core: Fix possible supplier PM-usage
counter imbalance") introduced a regression that causes suppliers
to be suspended prematurely for device links added during consumer
driver probe if the initial PM-runtime status of the consumer is
"suspended" and the consumer is resumed after adding the link and
before pm_runtime_put_suppliers() is called.  In that case,
pm_runtime_put_suppliers() will drop the rpm_active refcount for
the link by one and (since rpm_active is equal to two after the
preceding consumer resume) the supplier's PM-runtime usage counter
will be decremented, which may cause the supplier to suspend even
though the consumer's PM-runtime status is "active".

For this reason, partially revert commit 4c06c4e6cf as the problem
it tried to fix needs to be addressed somewhat differently, and
change pm_runtime_get_suppliers() and pm_runtime_put_suppliers() so
that the latter only drops rpm_active references acquired by the
former.  [This requires adding a new field to struct device_link,
but I coulnd't find a cleaner way to address the issue that would
work in all cases.]

This causes pm_runtime_put_suppliers() to effectively ignore device
links added during consumer probe, so device_link_add() doesn't need
to worry about ensuring that suppliers will remain active after
pm_runtime_put_suppliers() for links created with DL_FLAG_RPM_ACTIVE
set and it only needs to bump up rpm_active by one for those links,
so pm_runtime_active_link() is not necessary any more.

Fixes: 4c06c4e6cf ("driver core: Fix possible supplier PM-usage counter imbalance")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-20 11:18:07 +01:00

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/*
* pm_runtime.h - Device run-time power management helper functions.
*
* Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>
*
* This file is released under the GPLv2.
*/
#ifndef _LINUX_PM_RUNTIME_H
#define _LINUX_PM_RUNTIME_H
#include <linux/device.h>
#include <linux/notifier.h>
#include <linux/pm.h>
#include <linux/jiffies.h>
/* Runtime PM flag argument bits */
#define RPM_ASYNC 0x01 /* Request is asynchronous */
#define RPM_NOWAIT 0x02 /* Don't wait for concurrent
state change */
#define RPM_GET_PUT 0x04 /* Increment/decrement the
usage_count */
#define RPM_AUTO 0x08 /* Use autosuspend_delay */
#ifdef CONFIG_PM
extern struct workqueue_struct *pm_wq;
static inline bool queue_pm_work(struct work_struct *work)
{
return queue_work(pm_wq, work);
}
extern int pm_generic_runtime_suspend(struct device *dev);
extern int pm_generic_runtime_resume(struct device *dev);
extern int pm_runtime_force_suspend(struct device *dev);
extern int pm_runtime_force_resume(struct device *dev);
extern int __pm_runtime_idle(struct device *dev, int rpmflags);
extern int __pm_runtime_suspend(struct device *dev, int rpmflags);
extern int __pm_runtime_resume(struct device *dev, int rpmflags);
extern int pm_runtime_get_if_in_use(struct device *dev);
extern int pm_schedule_suspend(struct device *dev, unsigned int delay);
extern int __pm_runtime_set_status(struct device *dev, unsigned int status);
extern int pm_runtime_barrier(struct device *dev);
extern void pm_runtime_enable(struct device *dev);
extern void __pm_runtime_disable(struct device *dev, bool check_resume);
extern void pm_runtime_allow(struct device *dev);
extern void pm_runtime_forbid(struct device *dev);
extern void pm_runtime_no_callbacks(struct device *dev);
extern void pm_runtime_irq_safe(struct device *dev);
extern void __pm_runtime_use_autosuspend(struct device *dev, bool use);
extern void pm_runtime_set_autosuspend_delay(struct device *dev, int delay);
extern u64 pm_runtime_autosuspend_expiration(struct device *dev);
extern void pm_runtime_update_max_time_suspended(struct device *dev,
s64 delta_ns);
extern void pm_runtime_set_memalloc_noio(struct device *dev, bool enable);
extern void pm_runtime_clean_up_links(struct device *dev);
extern void pm_runtime_get_suppliers(struct device *dev);
extern void pm_runtime_put_suppliers(struct device *dev);
extern void pm_runtime_new_link(struct device *dev);
extern void pm_runtime_drop_link(struct device *dev);
static inline void pm_suspend_ignore_children(struct device *dev, bool enable)
{
dev->power.ignore_children = enable;
}
static inline void pm_runtime_get_noresume(struct device *dev)
{
atomic_inc(&dev->power.usage_count);
}
static inline void pm_runtime_put_noidle(struct device *dev)
{
atomic_add_unless(&dev->power.usage_count, -1, 0);
}
static inline bool pm_runtime_suspended(struct device *dev)
{
return dev->power.runtime_status == RPM_SUSPENDED
&& !dev->power.disable_depth;
}
static inline bool pm_runtime_active(struct device *dev)
{
return dev->power.runtime_status == RPM_ACTIVE
|| dev->power.disable_depth;
}
static inline bool pm_runtime_status_suspended(struct device *dev)
{
return dev->power.runtime_status == RPM_SUSPENDED;
}
static inline bool pm_runtime_enabled(struct device *dev)
{
return !dev->power.disable_depth;
}
static inline bool pm_runtime_callbacks_present(struct device *dev)
{
return !dev->power.no_callbacks;
}
static inline void pm_runtime_mark_last_busy(struct device *dev)
{
WRITE_ONCE(dev->power.last_busy, ktime_get_mono_fast_ns());
}
static inline bool pm_runtime_is_irq_safe(struct device *dev)
{
return dev->power.irq_safe;
}
extern u64 pm_runtime_suspended_time(struct device *dev);
#else /* !CONFIG_PM */
static inline bool queue_pm_work(struct work_struct *work) { return false; }
static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
static inline int pm_runtime_force_suspend(struct device *dev) { return 0; }
static inline int pm_runtime_force_resume(struct device *dev) { return 0; }
static inline int __pm_runtime_idle(struct device *dev, int rpmflags)
{
return -ENOSYS;
}
static inline int __pm_runtime_suspend(struct device *dev, int rpmflags)
{
return -ENOSYS;
}
static inline int __pm_runtime_resume(struct device *dev, int rpmflags)
{
return 1;
}
static inline int pm_schedule_suspend(struct device *dev, unsigned int delay)
{
return -ENOSYS;
}
static inline int pm_runtime_get_if_in_use(struct device *dev)
{
return -EINVAL;
}
static inline int __pm_runtime_set_status(struct device *dev,
unsigned int status) { return 0; }
static inline int pm_runtime_barrier(struct device *dev) { return 0; }
static inline void pm_runtime_enable(struct device *dev) {}
static inline void __pm_runtime_disable(struct device *dev, bool c) {}
static inline void pm_runtime_allow(struct device *dev) {}
static inline void pm_runtime_forbid(struct device *dev) {}
static inline void pm_suspend_ignore_children(struct device *dev, bool enable) {}
static inline void pm_runtime_get_noresume(struct device *dev) {}
static inline void pm_runtime_put_noidle(struct device *dev) {}
static inline bool pm_runtime_suspended(struct device *dev) { return false; }
static inline bool pm_runtime_active(struct device *dev) { return true; }
static inline bool pm_runtime_status_suspended(struct device *dev) { return false; }
static inline bool pm_runtime_enabled(struct device *dev) { return false; }
static inline void pm_runtime_no_callbacks(struct device *dev) {}
static inline void pm_runtime_irq_safe(struct device *dev) {}
static inline bool pm_runtime_is_irq_safe(struct device *dev) { return false; }
static inline bool pm_runtime_callbacks_present(struct device *dev) { return false; }
static inline void pm_runtime_mark_last_busy(struct device *dev) {}
static inline void __pm_runtime_use_autosuspend(struct device *dev,
bool use) {}
static inline void pm_runtime_set_autosuspend_delay(struct device *dev,
int delay) {}
static inline u64 pm_runtime_autosuspend_expiration(
struct device *dev) { return 0; }
static inline void pm_runtime_set_memalloc_noio(struct device *dev,
bool enable){}
static inline void pm_runtime_clean_up_links(struct device *dev) {}
static inline void pm_runtime_get_suppliers(struct device *dev) {}
static inline void pm_runtime_put_suppliers(struct device *dev) {}
static inline void pm_runtime_new_link(struct device *dev) {}
static inline void pm_runtime_drop_link(struct device *dev) {}
#endif /* !CONFIG_PM */
static inline int pm_runtime_idle(struct device *dev)
{
return __pm_runtime_idle(dev, 0);
}
static inline int pm_runtime_suspend(struct device *dev)
{
return __pm_runtime_suspend(dev, 0);
}
static inline int pm_runtime_autosuspend(struct device *dev)
{
return __pm_runtime_suspend(dev, RPM_AUTO);
}
static inline int pm_runtime_resume(struct device *dev)
{
return __pm_runtime_resume(dev, 0);
}
static inline int pm_request_idle(struct device *dev)
{
return __pm_runtime_idle(dev, RPM_ASYNC);
}
static inline int pm_request_resume(struct device *dev)
{
return __pm_runtime_resume(dev, RPM_ASYNC);
}
static inline int pm_request_autosuspend(struct device *dev)
{
return __pm_runtime_suspend(dev, RPM_ASYNC | RPM_AUTO);
}
static inline int pm_runtime_get(struct device *dev)
{
return __pm_runtime_resume(dev, RPM_GET_PUT | RPM_ASYNC);
}
static inline int pm_runtime_get_sync(struct device *dev)
{
return __pm_runtime_resume(dev, RPM_GET_PUT);
}
static inline int pm_runtime_put(struct device *dev)
{
return __pm_runtime_idle(dev, RPM_GET_PUT | RPM_ASYNC);
}
static inline int pm_runtime_put_autosuspend(struct device *dev)
{
return __pm_runtime_suspend(dev,
RPM_GET_PUT | RPM_ASYNC | RPM_AUTO);
}
static inline int pm_runtime_put_sync(struct device *dev)
{
return __pm_runtime_idle(dev, RPM_GET_PUT);
}
static inline int pm_runtime_put_sync_suspend(struct device *dev)
{
return __pm_runtime_suspend(dev, RPM_GET_PUT);
}
static inline int pm_runtime_put_sync_autosuspend(struct device *dev)
{
return __pm_runtime_suspend(dev, RPM_GET_PUT | RPM_AUTO);
}
static inline int pm_runtime_set_active(struct device *dev)
{
return __pm_runtime_set_status(dev, RPM_ACTIVE);
}
static inline int pm_runtime_set_suspended(struct device *dev)
{
return __pm_runtime_set_status(dev, RPM_SUSPENDED);
}
static inline void pm_runtime_disable(struct device *dev)
{
__pm_runtime_disable(dev, true);
}
static inline void pm_runtime_use_autosuspend(struct device *dev)
{
__pm_runtime_use_autosuspend(dev, true);
}
static inline void pm_runtime_dont_use_autosuspend(struct device *dev)
{
__pm_runtime_use_autosuspend(dev, false);
}
#endif
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