PM: Warn if interrupts are enabled during suspend-resume of sysdevs

Sysdevs have to be suspended and resumed with interrupts disabled and
things usually break in a way that's difficult to debug if one of
sysdev drivers enables interrupts by mistake during suspend or
resume.  Add extra checks that will generate warnings in such cases.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/base/sys.c

@@ -343,11 +343,15 @@ static void __sysdev_resume(struct sys_device *dev)
 	/* First, call the class-specific one */
 	if (cls->resume)
 		cls->resume(dev);
+	WARN_ONCE(!irqs_disabled(),
+		"Interrupts enabled after %pF\n", cls->resume);
 
 	/* Call auxillary drivers next. */
 	list_for_each_entry(drv, &cls->drivers, entry) {
 		if (drv->resume)
 			drv->resume(dev);
+		WARN_ONCE(!irqs_disabled(),
+			"Interrupts enabled after %pF\n", drv->resume);
 	}
 }
 
@@ -377,6 +381,9 @@ int sysdev_suspend(pm_message_t state)
 	if (ret)
 		return ret;
 
+	WARN_ONCE(!irqs_disabled(),
+		"Interrupts enabled while suspending system devices\n");
+
 	pr_debug("Suspending System Devices\n");
 
 	list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
@@ -393,6 +400,9 @@ int sysdev_suspend(pm_message_t state)
 					if (ret)
 						goto aux_driver;
 				}
+				WARN_ONCE(!irqs_disabled(),
+					"Interrupts enabled after %pF\n",
+					drv->suspend);
 			}
 
 			/* Now call the generic one */
@@ -400,6 +410,9 @@ int sysdev_suspend(pm_message_t state)
 				ret = cls->suspend(sysdev, state);
 				if (ret)
 					goto cls_driver;
+				WARN_ONCE(!irqs_disabled(),
+					"Interrupts enabled after %pF\n",
+					cls->suspend);
 			}
 		}
 	}
@@ -452,6 +465,9 @@ int sysdev_resume(void)
 {
 	struct sysdev_class *cls;
 
+	WARN_ONCE(!irqs_disabled(),
+		"Interrupts enabled while resuming system devices\n");
+
 	pr_debug("Resuming System Devices\n");
 
 	list_for_each_entry(cls, &system_kset->list, kset.kobj.entry) {