leds: Fix leds_list_lock locking issues

Covert leds_list_lock to a rw_sempahore to match previous LED trigger
locking fixes, fixing lock ordering.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

drivers/leds/led-class.c

@@ -106,9 +106,9 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 		goto err_out;
 
 	/* add to the list of leds */
-	write_lock(&leds_list_lock);
+	down_write(&leds_list_lock);
 	list_add_tail(&led_cdev->node, &leds_list);
-	write_unlock(&leds_list_lock);
+	up_write(&leds_list_lock);
 
 #ifdef CONFIG_LEDS_TRIGGERS
 	init_rwsem(&led_cdev->trigger_lock);
@@ -155,9 +155,9 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
 
 	device_unregister(led_cdev->dev);
 
-	write_lock(&leds_list_lock);
+	down_write(&leds_list_lock);
 	list_del(&led_cdev->node);
-	write_unlock(&leds_list_lock);
+	up_write(&leds_list_lock);
 }
 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 

drivers/leds/led-core.c

@@ -14,11 +14,11 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
-#include <linux/spinlock.h>
+#include <linux/rwsem.h>
 #include <linux/leds.h>
 #include "leds.h"
 
-DEFINE_RWLOCK(leds_list_lock);
+DECLARE_RWSEM(leds_list_lock);
 LIST_HEAD(leds_list);
 
 EXPORT_SYMBOL_GPL(leds_list);

drivers/leds/led-triggers.c

@@ -169,7 +169,7 @@ int led_trigger_register(struct led_trigger *trigger)
 	up_write(&triggers_list_lock);
 
 	/* Register with any LEDs that have this as a default trigger */
-	read_lock(&leds_list_lock);
+	down_read(&leds_list_lock);
 	list_for_each_entry(led_cdev, &leds_list, node) {
 		down_write(&led_cdev->trigger_lock);
 		if (!led_cdev->trigger && led_cdev->default_trigger &&
@@ -177,7 +177,7 @@ int led_trigger_register(struct led_trigger *trigger)
 			led_trigger_set(led_cdev, trigger);
 		up_write(&led_cdev->trigger_lock);
 	}
-	read_unlock(&leds_list_lock);
+	up_read(&leds_list_lock);
 
 	return 0;
 }
@@ -212,14 +212,14 @@ void led_trigger_unregister(struct led_trigger *trigger)
 	up_write(&triggers_list_lock);
 
 	/* Remove anyone actively using this trigger */
-	read_lock(&leds_list_lock);
+	down_read(&leds_list_lock);
 	list_for_each_entry(led_cdev, &leds_list, node) {
 		down_write(&led_cdev->trigger_lock);
 		if (led_cdev->trigger == trigger)
 			led_trigger_set(led_cdev, NULL);
 		up_write(&led_cdev->trigger_lock);
 	}
-	read_unlock(&leds_list_lock);
+	up_read(&leds_list_lock);
 }
 
 void led_trigger_unregister_simple(struct led_trigger *trigger)

drivers/leds/leds.h

@@ -14,6 +14,7 @@
 #define __LEDS_H_INCLUDED
 
 #include <linux/device.h>
+#include <linux/rwsem.h>
 #include <linux/leds.h>
 
 static inline void led_set_brightness(struct led_classdev *led_cdev,
@@ -26,7 +27,7 @@ static inline void led_set_brightness(struct led_classdev *led_cdev,
 		led_cdev->brightness_set(led_cdev, value);
 }
 
-extern rwlock_t leds_list_lock;
+extern struct rw_semaphore leds_list_lock;
 extern struct list_head leds_list;
 
 #ifdef CONFIG_LEDS_TRIGGERS