From dc47206e552c0850ad11f7e9a1fca0a3c92f5d65 Mon Sep 17 00:00:00 2001 From: Richard Purdie Date: Sat, 10 Nov 2007 13:29:04 +0000 Subject: [PATCH] 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 --- drivers/leds/led-class.c | 6 ++--- drivers/leds/led-triggers.c | 49 +++++++++++++++++++------------------ include/linux/leds.h | 3 ++- 3 files changed, 30 insertions(+), 28 deletions(-) diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 4211293ce8..ba8b04b03b 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -111,7 +111,7 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) write_unlock(&leds_list_lock); #ifdef CONFIG_LEDS_TRIGGERS - rwlock_init(&led_cdev->trigger_lock); + init_rwsem(&led_cdev->trigger_lock); rc = device_create_file(led_cdev->dev, &dev_attr_trigger); if (rc) @@ -147,10 +147,10 @@ void led_classdev_unregister(struct led_classdev *led_cdev) device_remove_file(led_cdev->dev, &dev_attr_brightness); #ifdef CONFIG_LEDS_TRIGGERS device_remove_file(led_cdev->dev, &dev_attr_trigger); - write_lock(&led_cdev->trigger_lock); + down_write(&led_cdev->trigger_lock); if (led_cdev->trigger) led_trigger_set(led_cdev, NULL); - write_unlock(&led_cdev->trigger_lock); + up_write(&led_cdev->trigger_lock); #endif device_unregister(led_cdev->dev); diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 575368c2b1..0bdb786210 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -19,13 +19,14 @@ #include #include #include +#include #include #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 @@ ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, 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 @@ ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, 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 @@ ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, 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 @@ void led_trigger_set_default(struct led_classdev *led_cdev) 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 @@ int led_trigger_register(struct led_trigger *trigger) 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 @@ void led_trigger_unregister(struct led_trigger *trigger) 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); } diff --git a/include/linux/leds.h b/include/linux/leds.h index dc1178f618..b4130ff58d 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -14,6 +14,7 @@ #include #include +#include struct device; /* @@ -43,7 +44,7 @@ struct led_classdev { #ifdef CONFIG_LEDS_TRIGGERS /* Protects the trigger data below */ - rwlock_t trigger_lock; + struct rw_semaphore trigger_lock; struct led_trigger *trigger; struct list_head trig_list; -- 2.39.5