leds: Fix led trigger locking bugs
Convert part of the led trigger core from rw spinlocks to rw
semaphores. We're calling functions which can sleep from invalid
contexts otherwise. Fixes bug #9264.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 575368c..0bdb786 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -19,13 +19,14 @@
#include <linux/device.h>
#include <linux/sysdev.h>
#include <linux/timer.h>
+#include <linux/rwsem.h>
#include <linux/leds.h>
#include "leds.h"
/*
* Nests outside led_cdev->trigger_lock
*/
-static DEFINE_RWLOCK(triggers_list_lock);
+static DECLARE_RWSEM(triggers_list_lock);
static LIST_HEAD(trigger_list);
ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
@@ -44,24 +45,24 @@
trigger_name[len - 1] = '\0';
if (!strcmp(trigger_name, "none")) {
- write_lock(&led_cdev->trigger_lock);
+ down_write(&led_cdev->trigger_lock);
led_trigger_set(led_cdev, NULL);
- write_unlock(&led_cdev->trigger_lock);
+ up_write(&led_cdev->trigger_lock);
return count;
}
- read_lock(&triggers_list_lock);
+ down_read(&triggers_list_lock);
list_for_each_entry(trig, &trigger_list, next_trig) {
if (!strcmp(trigger_name, trig->name)) {
- write_lock(&led_cdev->trigger_lock);
+ down_write(&led_cdev->trigger_lock);
led_trigger_set(led_cdev, trig);
- write_unlock(&led_cdev->trigger_lock);
+ up_write(&led_cdev->trigger_lock);
- read_unlock(&triggers_list_lock);
+ up_read(&triggers_list_lock);
return count;
}
}
- read_unlock(&triggers_list_lock);
+ up_read(&triggers_list_lock);
return -EINVAL;
}
@@ -74,8 +75,8 @@
struct led_trigger *trig;
int len = 0;
- read_lock(&triggers_list_lock);
- read_lock(&led_cdev->trigger_lock);
+ down_read(&triggers_list_lock);
+ down_read(&led_cdev->trigger_lock);
if (!led_cdev->trigger)
len += sprintf(buf+len, "[none] ");
@@ -89,8 +90,8 @@
else
len += sprintf(buf+len, "%s ", trig->name);
}
- read_unlock(&led_cdev->trigger_lock);
- read_unlock(&triggers_list_lock);
+ up_read(&led_cdev->trigger_lock);
+ up_read(&triggers_list_lock);
len += sprintf(len+buf, "\n");
return len;
@@ -145,14 +146,14 @@
if (!led_cdev->default_trigger)
return;
- read_lock(&triggers_list_lock);
- write_lock(&led_cdev->trigger_lock);
+ down_read(&triggers_list_lock);
+ down_write(&led_cdev->trigger_lock);
list_for_each_entry(trig, &trigger_list, next_trig) {
if (!strcmp(led_cdev->default_trigger, trig->name))
led_trigger_set(led_cdev, trig);
}
- write_unlock(&led_cdev->trigger_lock);
- read_unlock(&triggers_list_lock);
+ up_write(&led_cdev->trigger_lock);
+ up_read(&triggers_list_lock);
}
int led_trigger_register(struct led_trigger *trigger)
@@ -163,18 +164,18 @@
INIT_LIST_HEAD(&trigger->led_cdevs);
/* Add to the list of led triggers */
- write_lock(&triggers_list_lock);
+ down_write(&triggers_list_lock);
list_add_tail(&trigger->next_trig, &trigger_list);
- write_unlock(&triggers_list_lock);
+ up_write(&triggers_list_lock);
/* Register with any LEDs that have this as a default trigger */
read_lock(&leds_list_lock);
list_for_each_entry(led_cdev, &leds_list, node) {
- write_lock(&led_cdev->trigger_lock);
+ down_write(&led_cdev->trigger_lock);
if (!led_cdev->trigger && led_cdev->default_trigger &&
!strcmp(led_cdev->default_trigger, trigger->name))
led_trigger_set(led_cdev, trigger);
- write_unlock(&led_cdev->trigger_lock);
+ up_write(&led_cdev->trigger_lock);
}
read_unlock(&leds_list_lock);
@@ -206,17 +207,17 @@
struct led_classdev *led_cdev;
/* Remove from the list of led triggers */
- write_lock(&triggers_list_lock);
+ down_write(&triggers_list_lock);
list_del(&trigger->next_trig);
- write_unlock(&triggers_list_lock);
+ up_write(&triggers_list_lock);
/* Remove anyone actively using this trigger */
read_lock(&leds_list_lock);
list_for_each_entry(led_cdev, &leds_list, node) {
- write_lock(&led_cdev->trigger_lock);
+ down_write(&led_cdev->trigger_lock);
if (led_cdev->trigger == trigger)
led_trigger_set(led_cdev, NULL);
- write_unlock(&led_cdev->trigger_lock);
+ up_write(&led_cdev->trigger_lock);
}
read_unlock(&leds_list_lock);
}