ACPI: thinkpad-acpi: keep track of module state

Keep track of module state (init, running, exit).  This makes it trivially
easy to avoid running any interrupt handlers, threads, or any other async
activity before we are ready, or when we want to go away.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 0ced9d6..2155139 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -117,6 +117,12 @@
 
 #define __unused __attribute__ ((unused))
 
+static enum {
+	TPACPI_LIFE_INIT = 0,
+	TPACPI_LIFE_RUNNING,
+	TPACPI_LIFE_EXITING,
+} tpacpi_lifecycle;
+
 /****************************************************************************
  ****************************************************************************
  *
@@ -342,6 +348,9 @@
 {
 	struct ibm_struct *ibm = data;
 
+	if (tpacpi_lifecycle != TPACPI_LIFE_RUNNING)
+		return;
+
 	if (!ibm || !ibm->acpi || !ibm->acpi->notify)
 		return;
 
@@ -3899,6 +3908,9 @@
 {
 	int rc;
 
+	if (tpacpi_lifecycle != TPACPI_LIFE_RUNNING)
+		return;
+
 	printk(IBM_NOTICE "fan watchdog: enabling fan\n");
 	rc = fan_set_enable();
 	if (rc < 0) {
@@ -3919,7 +3931,8 @@
 	if (fan_watchdog_active)
 		cancel_delayed_work(&fan_watchdog_task);
 
-	if (fan_watchdog_maxinterval > 0) {
+	if (fan_watchdog_maxinterval > 0 &&
+	    tpacpi_lifecycle != TPACPI_LIFE_EXITING) {
 		fan_watchdog_active = 1;
 		if (!schedule_delayed_work(&fan_watchdog_task,
 				msecs_to_jiffies(fan_watchdog_maxinterval
@@ -4685,6 +4698,8 @@
 {
 	int ret, i;
 
+	tpacpi_lifecycle = TPACPI_LIFE_INIT;
+
 	/* Parameter checking */
 	if (hotkey_report_mode > 2)
 		return -EINVAL;
@@ -4781,6 +4796,7 @@
 		tp_features.input_device_registered = 1;
 	}
 
+	tpacpi_lifecycle = TPACPI_LIFE_RUNNING;
 	return 0;
 }
 
@@ -4788,6 +4804,8 @@
 {
 	struct ibm_struct *ibm, *itmp;
 
+	tpacpi_lifecycle = TPACPI_LIFE_EXITING;
+
 	list_for_each_entry_safe_reverse(ibm, itmp,
 					 &tpacpi_all_drivers,
 					 all_drivers) {