@@ -580,6 +580,19 @@ static void pm_wakeup_update_hit_counts(void)
rcu_read_unlock();
}
+
+bool pm_wakeup_in_progress(void)
+{
+ unsigned int cnt, inpr;
+ unsigned long flags;
+
+ spin_lock_irqsave(&events_lock, flags);
+ split_counters(&cnt, &inpr);
+ spin_unlock_irqrestore(&events_lock, flags);
+
+ return (inpr != 0);
+}
+
/**
* pm_wakeup_pending - Check if power transition in progress should be aborted.
*
@@ -294,6 +294,7 @@ extern int unregister_pm_notifier(struct notifier_block *nb);
extern bool events_check_enabled;
extern bool pm_wakeup_pending(void);
+extern bool pm_wakeup_in_progress(void);
extern bool pm_get_wakeup_count(unsigned int *count);
extern bool pm_save_wakeup_count(unsigned int count);
#else /* !CONFIG_PM_SLEEP */
@@ -311,6 +312,8 @@ static inline int unregister_pm_notifier(struct notifier_block *nb)
#define pm_notifier(fn, pri) do { (void)(fn); } while (0)
static inline bool pm_wakeup_pending(void) { return false; }
+static inline bool pm_wakeup_in_progress(void) { return false; }
+
#endif /* !CONFIG_PM_SLEEP */
extern struct mutex pm_mutex;
@@ -611,6 +611,11 @@ int hibernate(void)
goto Unlock;
}
+ if (pm_wakeup_in_progress()) {
+ error = -EBUSY;
+ goto Unlock;
+ }
+
pm_prepare_console();
error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
if (error)
@@ -281,6 +281,11 @@ int enter_state(suspend_state_t state)
if (!mutex_trylock(&pm_mutex))
return -EBUSY;
+ if (pm_wakeup_in_progress()) {
+ error = -EBUSY;
+ goto Unlock;
+ }
+
printk(KERN_INFO "PM: Syncing filesystems ... ");
sys_sync();
printk("done.\n");
With the current pm_stay_awake/pm_relax api, reads to /sys/power/wakeup_count will block when pm_stay_awake() has been called. Then once pm_relax() returns, the read will unblock and return the wakeup_count value. This value can be echo'ed back into wakeup_count, and if no other wakeup events have occured, the system can be suspended by calling "echo mem > /sys/power/state". This method is somewhat advisory, as if a wakeup event has occured between the reading of /sys/power/wakeup_count and the attempt to suspend, that attempt to suspend will fail. However, if a second attmept to suspend is tried, without checking /sys/power/wakeup_count, the suspend will succeed. Similarly, if pm_stay_awake() has been called, and then a suspend is attepted wihtout checking /sys/power/wakeup_count, the suspend will succeed, despite the pm_relax() call not having been made. This patch tries to make the pm_stay_awake() call a bit more enforcing, such that any attempt to suspend that occurs while a wakeup is in progress will fail. Once the matching pm_relax() has been called, suspend will succeed. This does not change the blocking behavior of /sys/power/wakeup_count, or the suspend failure if a stale wakeup count has been echo'ed into the /sys/power/wakeup_count. Also modified the hibernate path in the same way. Signed-off-by: John Stultz <john.stultz@linaro.org> --- drivers/base/power/wakeup.c | 13 +++++++++++++ include/linux/suspend.h | 3 +++ kernel/power/hibernate.c | 5 +++++ kernel/power/suspend.c | 5 +++++ 4 files changed, 26 insertions(+), 0 deletions(-)