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Commit 72f8da32 authored by Richard Purdie's avatar Richard Purdie
Browse files

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: default avatarRichard Purdie <rpurdie@rpsys.net>
parent e697789d

drivers/leds/led-class.c

+4 −4
Original line number Diff line number Diff line
@@ -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

+2 −2
Original line number Diff line number Diff line
@@ -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

+4 −4
Original line number Diff line number Diff line
@@ -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

+2 −1
Original line number Diff line number Diff line
@@ -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