PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

Introduce struct wakeup_source for representing system wakeup sources
within the kernel and for collecting statistics related to them.
Make the recently introduced helper functions pm_wakeup_event(),
pm_stay_awake() and pm_relax() use struct wakeup_source objects
internally, so that wakeup statistics associated with wakeup devices
can be collected and reported in a consistent way (the definition of
pm_relax() is changed, which is harmless, because this function is
not called directly by anyone yet).  Introduce new wakeup-related
sysfs device attributes in /sys/devices/.../power for reporting the
device wakeup statistics.

Change the global wakeup events counters event_count and
events_in_progress into atomic variables, so that it is not necessary
to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake()
and pm_relax(), which should allow us to avoid lock contention in
these functions on SMP systems with many wakeup devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 12 deletions

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 52e8c55ff314..a84118911ced 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -448,23 +448,24 @@ enum rpm_request {
         RPM_REQ_RESUME,
 };
 
+struct wakeup_source;
+
 struct dev_pm_info {
         pm_message_t            power_state;
         unsigned int            can_wakeup:1;
-        unsigned int            should_wakeup:1;
         unsigned                async_suspend:1;
         enum dpm_state          status;         /* Owned by the PM core */
+        spinlock_t              lock;
 #ifdef CONFIG_PM_SLEEP
         struct list_head        entry;
         struct completion       completion;
-        unsigned long           wakeup_count;
+        struct wakeup_source    *wakeup;
 #endif
 #ifdef CONFIG_PM_RUNTIME
         struct timer_list       suspend_timer;
         unsigned long           timer_expires;
         struct work_struct      work;
         wait_queue_head_t       wait_queue;
-        spinlock_t              lock;
         atomic_t                usage_count;
         atomic_t                child_count;
         unsigned int            disable_depth:3;
@@ -559,11 +560,6 @@ extern void __suspend_report_result(const char *function, void *fn, int ret);
         } while (0)
 
 extern void device_pm_wait_for_dev(struct device *sub, struct device *dev);
-
-/* drivers/base/power/wakeup.c */
-extern void pm_wakeup_event(struct device *dev, unsigned int msec);
-extern void pm_stay_awake(struct device *dev);
-extern void pm_relax(void);
 #else /* !CONFIG_PM_SLEEP */
 
 #define device_pm_lock() do {} while (0)
@@ -577,10 +573,6 @@ static inline int dpm_suspend_start(pm_message_t state)
 #define suspend_report_result(fn, ret)          do {} while (0)
 
 static inline void device_pm_wait_for_dev(struct device *a, struct device *b) {}
-
-static inline void pm_wakeup_event(struct device *dev, unsigned int msec) {}
-static inline void pm_stay_awake(struct device *dev) {}
-static inline void pm_relax(void) {}
 #endif /* !CONFIG_PM_SLEEP */
 
 /* How to reorder dpm_list after device_move() */