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, 4 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index f06ad6eff37a..6b12a0cf4d9f 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -237,18 +237,18 @@ static ssize_t wakeup_count_show(struct kobject *kobj,
                                 struct kobj_attribute *attr,
                                 char *buf)
 {
-        unsigned long val;
+        unsigned int val;
 
-        return pm_get_wakeup_count(&val) ? sprintf(buf, "%lu\n", val) : -EINTR;
+        return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
 }
 
 static ssize_t wakeup_count_store(struct kobject *kobj,
                                 struct kobj_attribute *attr,
                                 const char *buf, size_t n)
 {
-        unsigned long val;
+        unsigned int val;
 
-        if (sscanf(buf, "%lu", &val) == 1) {
+        if (sscanf(buf, "%u", &val) == 1) {
                 if (pm_save_wakeup_count(val))
                         return n;
         }