PM: Improve error code of pm_notifier_call_chain()

This enables pm_notifier_call_chain() to get the actual error code
in the callback rather than always assume -EINVAL by converting all
PM notifier calls to return encapsulate error code with
notifier_from_errno().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/char/apm-emulation.c

@@ -606,7 +606,7 @@ static int apm_suspend_notifier(struct notifier_block *nb,
 			return NOTIFY_OK;
 
 		/* interrupted by signal */
-		return NOTIFY_BAD;
+		return notifier_from_errno(err);
 
 	case PM_POST_SUSPEND:
 		/*

drivers/s390/char/vmwatchdog.c

@@ -258,13 +258,13 @@ static int vmwdt_suspend(void)
 	if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open)) {
 		pr_err("The system cannot be suspended while the watchdog"
 			" is in use\n");
-		return NOTIFY_BAD;
+		return notifier_from_errno(-EBUSY);
 	}
 	if (test_bit(VMWDT_RUNNING, &vmwdt_is_open)) {
 		clear_bit(VMWDT_OPEN, &vmwdt_is_open);
 		pr_err("The system cannot be suspended while the watchdog"
 			" is running\n");
-		return NOTIFY_BAD;
+		return notifier_from_errno(-EBUSY);
 	}
 	return NOTIFY_DONE;
 }

drivers/s390/cio/css.c

@@ -814,8 +814,8 @@ static int css_power_event(struct notifier_block *this, unsigned long event,
 				mutex_unlock(&css->mutex);
 				continue;
 			}
-			if (__chsc_do_secm(css, 0))
-				ret = NOTIFY_BAD;
+			ret = __chsc_do_secm(css, 0);
+			ret = notifier_from_errno(ret);
 			mutex_unlock(&css->mutex);
 		}
 		break;
@@ -831,8 +831,8 @@ static int css_power_event(struct notifier_block *this, unsigned long event,
 				mutex_unlock(&css->mutex);
 				continue;
 			}
-			if (__chsc_do_secm(css, 1))
-				ret = NOTIFY_BAD;
+			ret = __chsc_do_secm(css, 1);
+			ret = notifier_from_errno(ret);
 			mutex_unlock(&css->mutex);
 		}
 		/* search for subchannels, which appeared during hibernation */

kernel/power/main.c

@@ -37,8 +37,9 @@ EXPORT_SYMBOL_GPL(unregister_pm_notifier);
 
 int pm_notifier_call_chain(unsigned long val)
 {
-	return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
-			== NOTIFY_BAD) ? -EINVAL : 0;
+	int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
+
+	return notifier_to_errno(ret);
 }
 
 /* If set, devices may be suspended and resumed asynchronously. */