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![Oleh Kravchenko](/assets/img/avatar_default.png)
Error was detected by PVS-Studio:
V522 Dereferencing of the null pointer 'led_cdev->trigger' might take place.
Fixes: 2282e125a4
("leds: triggers: let struct led_trigger::activate() return an error code")
Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
401 lines
9.7 KiB
C
401 lines
9.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* LED Triggers Core
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*
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* Copyright 2005-2007 Openedhand Ltd.
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*
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* Author: Richard Purdie <rpurdie@openedhand.com>
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*/
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/device.h>
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#include <linux/timer.h>
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#include <linux/rwsem.h>
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#include <linux/leds.h>
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#include <linux/slab.h>
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#include "leds.h"
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/*
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* Nests outside led_cdev->trigger_lock
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*/
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static DECLARE_RWSEM(triggers_list_lock);
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LIST_HEAD(trigger_list);
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/* Used by LED Class */
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ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct led_trigger *trig;
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int ret = count;
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mutex_lock(&led_cdev->led_access);
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if (led_sysfs_is_disabled(led_cdev)) {
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ret = -EBUSY;
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goto unlock;
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}
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if (sysfs_streq(buf, "none")) {
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led_trigger_remove(led_cdev);
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goto unlock;
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}
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down_read(&triggers_list_lock);
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list_for_each_entry(trig, &trigger_list, next_trig) {
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if (sysfs_streq(buf, trig->name)) {
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down_write(&led_cdev->trigger_lock);
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led_trigger_set(led_cdev, trig);
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up_write(&led_cdev->trigger_lock);
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up_read(&triggers_list_lock);
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goto unlock;
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}
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}
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/* we come here only if buf matches no trigger */
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ret = -EINVAL;
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up_read(&triggers_list_lock);
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unlock:
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mutex_unlock(&led_cdev->led_access);
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return ret;
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}
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EXPORT_SYMBOL_GPL(led_trigger_store);
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ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct led_trigger *trig;
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int len = 0;
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down_read(&triggers_list_lock);
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down_read(&led_cdev->trigger_lock);
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if (!led_cdev->trigger)
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len += scnprintf(buf+len, PAGE_SIZE - len, "[none] ");
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else
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len += scnprintf(buf+len, PAGE_SIZE - len, "none ");
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list_for_each_entry(trig, &trigger_list, next_trig) {
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if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
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trig->name))
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len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ",
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trig->name);
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else
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len += scnprintf(buf+len, PAGE_SIZE - len, "%s ",
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trig->name);
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}
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up_read(&led_cdev->trigger_lock);
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up_read(&triggers_list_lock);
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len += scnprintf(len+buf, PAGE_SIZE - len, "\n");
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return len;
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}
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EXPORT_SYMBOL_GPL(led_trigger_show);
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/* Caller must ensure led_cdev->trigger_lock held */
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int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
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{
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unsigned long flags;
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char *event = NULL;
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char *envp[2];
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const char *name;
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int ret;
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if (!led_cdev->trigger && !trig)
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return 0;
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name = trig ? trig->name : "none";
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event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
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/* Remove any existing trigger */
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if (led_cdev->trigger) {
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write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
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list_del(&led_cdev->trig_list);
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write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
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flags);
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cancel_work_sync(&led_cdev->set_brightness_work);
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led_stop_software_blink(led_cdev);
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if (led_cdev->trigger->deactivate)
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led_cdev->trigger->deactivate(led_cdev);
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device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
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led_cdev->trigger = NULL;
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led_cdev->trigger_data = NULL;
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led_cdev->activated = false;
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led_set_brightness(led_cdev, LED_OFF);
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}
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if (trig) {
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write_lock_irqsave(&trig->leddev_list_lock, flags);
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list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
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write_unlock_irqrestore(&trig->leddev_list_lock, flags);
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led_cdev->trigger = trig;
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if (trig->activate)
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ret = trig->activate(led_cdev);
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else
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ret = 0;
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if (ret)
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goto err_activate;
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ret = device_add_groups(led_cdev->dev, trig->groups);
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if (ret) {
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dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
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goto err_add_groups;
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}
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}
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if (event) {
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envp[0] = event;
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envp[1] = NULL;
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if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
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dev_err(led_cdev->dev,
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"%s: Error sending uevent\n", __func__);
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kfree(event);
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}
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return 0;
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err_add_groups:
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if (trig->deactivate)
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trig->deactivate(led_cdev);
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err_activate:
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write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
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list_del(&led_cdev->trig_list);
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write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
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led_cdev->trigger = NULL;
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led_cdev->trigger_data = NULL;
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led_set_brightness(led_cdev, LED_OFF);
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kfree(event);
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return ret;
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}
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EXPORT_SYMBOL_GPL(led_trigger_set);
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void led_trigger_remove(struct led_classdev *led_cdev)
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{
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down_write(&led_cdev->trigger_lock);
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led_trigger_set(led_cdev, NULL);
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up_write(&led_cdev->trigger_lock);
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}
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EXPORT_SYMBOL_GPL(led_trigger_remove);
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void led_trigger_set_default(struct led_classdev *led_cdev)
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{
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struct led_trigger *trig;
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if (!led_cdev->default_trigger)
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return;
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down_read(&triggers_list_lock);
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down_write(&led_cdev->trigger_lock);
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list_for_each_entry(trig, &trigger_list, next_trig) {
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if (!strcmp(led_cdev->default_trigger, trig->name)) {
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led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
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led_trigger_set(led_cdev, trig);
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break;
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}
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}
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up_write(&led_cdev->trigger_lock);
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up_read(&triggers_list_lock);
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}
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EXPORT_SYMBOL_GPL(led_trigger_set_default);
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void led_trigger_rename_static(const char *name, struct led_trigger *trig)
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{
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/* new name must be on a temporary string to prevent races */
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BUG_ON(name == trig->name);
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down_write(&triggers_list_lock);
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/* this assumes that trig->name was originaly allocated to
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* non constant storage */
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strcpy((char *)trig->name, name);
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up_write(&triggers_list_lock);
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}
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EXPORT_SYMBOL_GPL(led_trigger_rename_static);
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/* LED Trigger Interface */
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int led_trigger_register(struct led_trigger *trig)
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{
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struct led_classdev *led_cdev;
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struct led_trigger *_trig;
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rwlock_init(&trig->leddev_list_lock);
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INIT_LIST_HEAD(&trig->led_cdevs);
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down_write(&triggers_list_lock);
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/* Make sure the trigger's name isn't already in use */
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list_for_each_entry(_trig, &trigger_list, next_trig) {
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if (!strcmp(_trig->name, trig->name)) {
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up_write(&triggers_list_lock);
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return -EEXIST;
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}
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}
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/* Add to the list of led triggers */
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list_add_tail(&trig->next_trig, &trigger_list);
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up_write(&triggers_list_lock);
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/* Register with any LEDs that have this as a default trigger */
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down_read(&leds_list_lock);
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list_for_each_entry(led_cdev, &leds_list, node) {
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down_write(&led_cdev->trigger_lock);
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if (!led_cdev->trigger && led_cdev->default_trigger &&
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!strcmp(led_cdev->default_trigger, trig->name)) {
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led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
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led_trigger_set(led_cdev, trig);
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}
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up_write(&led_cdev->trigger_lock);
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}
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up_read(&leds_list_lock);
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return 0;
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}
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EXPORT_SYMBOL_GPL(led_trigger_register);
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void led_trigger_unregister(struct led_trigger *trig)
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{
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struct led_classdev *led_cdev;
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if (list_empty_careful(&trig->next_trig))
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return;
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/* Remove from the list of led triggers */
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down_write(&triggers_list_lock);
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list_del_init(&trig->next_trig);
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up_write(&triggers_list_lock);
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/* Remove anyone actively using this trigger */
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down_read(&leds_list_lock);
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list_for_each_entry(led_cdev, &leds_list, node) {
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down_write(&led_cdev->trigger_lock);
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if (led_cdev->trigger == trig)
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led_trigger_set(led_cdev, NULL);
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up_write(&led_cdev->trigger_lock);
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}
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up_read(&leds_list_lock);
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}
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EXPORT_SYMBOL_GPL(led_trigger_unregister);
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static void devm_led_trigger_release(struct device *dev, void *res)
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{
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led_trigger_unregister(*(struct led_trigger **)res);
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}
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int devm_led_trigger_register(struct device *dev,
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struct led_trigger *trig)
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{
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struct led_trigger **dr;
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int rc;
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dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
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GFP_KERNEL);
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if (!dr)
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return -ENOMEM;
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*dr = trig;
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rc = led_trigger_register(trig);
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if (rc)
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devres_free(dr);
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else
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devres_add(dev, dr);
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return rc;
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}
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EXPORT_SYMBOL_GPL(devm_led_trigger_register);
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/* Simple LED Tigger Interface */
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void led_trigger_event(struct led_trigger *trig,
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enum led_brightness brightness)
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{
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struct led_classdev *led_cdev;
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if (!trig)
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return;
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read_lock(&trig->leddev_list_lock);
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list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
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led_set_brightness(led_cdev, brightness);
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read_unlock(&trig->leddev_list_lock);
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}
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EXPORT_SYMBOL_GPL(led_trigger_event);
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static void led_trigger_blink_setup(struct led_trigger *trig,
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unsigned long *delay_on,
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unsigned long *delay_off,
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int oneshot,
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int invert)
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{
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struct led_classdev *led_cdev;
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if (!trig)
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return;
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read_lock(&trig->leddev_list_lock);
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list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
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if (oneshot)
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led_blink_set_oneshot(led_cdev, delay_on, delay_off,
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invert);
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else
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led_blink_set(led_cdev, delay_on, delay_off);
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}
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read_unlock(&trig->leddev_list_lock);
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}
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void led_trigger_blink(struct led_trigger *trig,
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unsigned long *delay_on,
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unsigned long *delay_off)
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{
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led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
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}
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EXPORT_SYMBOL_GPL(led_trigger_blink);
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void led_trigger_blink_oneshot(struct led_trigger *trig,
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unsigned long *delay_on,
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unsigned long *delay_off,
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int invert)
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{
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led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
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}
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EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
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void led_trigger_register_simple(const char *name, struct led_trigger **tp)
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{
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struct led_trigger *trig;
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int err;
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trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
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if (trig) {
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trig->name = name;
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err = led_trigger_register(trig);
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if (err < 0) {
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kfree(trig);
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trig = NULL;
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pr_warn("LED trigger %s failed to register (%d)\n",
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name, err);
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}
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} else {
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pr_warn("LED trigger %s failed to register (no memory)\n",
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name);
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}
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*tp = trig;
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}
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EXPORT_SYMBOL_GPL(led_trigger_register_simple);
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void led_trigger_unregister_simple(struct led_trigger *trig)
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{
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if (trig)
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led_trigger_unregister(trig);
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kfree(trig);
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}
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EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
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