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Calling device_add causes an inital uevent for that device to be generated. The power_supply uevent function calls the drivers get_property function, which might causes the driver to update its state, which again might causes the driver to call power_supply_changed(). Since the power_supplys changed_work has not been initialized at this point the behavior is undefined and can result in an OOPS. This patch fixes the issue by initializing the power_supplys changed_work prior to adding the power_supplys device to the device tree. Reported-by: Grazvydas Ignotas <notasas@gmail.com> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Tested-by: Grazvydas Ignotas <notasas@gmail.com>
236 lines
5.4 KiB
C
236 lines
5.4 KiB
C
/*
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* Universal power supply monitor class
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*
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* Copyright © 2007 Anton Vorontsov <cbou@mail.ru>
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* Copyright © 2004 Szabolcs Gyurko
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* Copyright © 2003 Ian Molton <spyro@f2s.com>
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*
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* Modified: 2004, Oct Szabolcs Gyurko
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*
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* You may use this code as per GPL version 2
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/power_supply.h>
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#include "power_supply.h"
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/* exported for the APM Power driver, APM emulation */
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struct class *power_supply_class;
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EXPORT_SYMBOL_GPL(power_supply_class);
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static struct device_type power_supply_dev_type;
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static int __power_supply_changed_work(struct device *dev, void *data)
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{
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struct power_supply *psy = (struct power_supply *)data;
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struct power_supply *pst = dev_get_drvdata(dev);
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int i;
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for (i = 0; i < psy->num_supplicants; i++)
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if (!strcmp(psy->supplied_to[i], pst->name)) {
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if (pst->external_power_changed)
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pst->external_power_changed(pst);
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}
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return 0;
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}
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static void power_supply_changed_work(struct work_struct *work)
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{
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struct power_supply *psy = container_of(work, struct power_supply,
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changed_work);
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dev_dbg(psy->dev, "%s\n", __func__);
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class_for_each_device(power_supply_class, NULL, psy,
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__power_supply_changed_work);
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power_supply_update_leds(psy);
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kobject_uevent(&psy->dev->kobj, KOBJ_CHANGE);
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}
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void power_supply_changed(struct power_supply *psy)
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{
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dev_dbg(psy->dev, "%s\n", __func__);
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schedule_work(&psy->changed_work);
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}
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EXPORT_SYMBOL_GPL(power_supply_changed);
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static int __power_supply_am_i_supplied(struct device *dev, void *data)
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{
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union power_supply_propval ret = {0,};
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struct power_supply *psy = (struct power_supply *)data;
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struct power_supply *epsy = dev_get_drvdata(dev);
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int i;
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for (i = 0; i < epsy->num_supplicants; i++) {
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if (!strcmp(epsy->supplied_to[i], psy->name)) {
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if (epsy->get_property(epsy,
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POWER_SUPPLY_PROP_ONLINE, &ret))
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continue;
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if (ret.intval)
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return ret.intval;
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}
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}
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return 0;
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}
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int power_supply_am_i_supplied(struct power_supply *psy)
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{
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int error;
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error = class_for_each_device(power_supply_class, NULL, psy,
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__power_supply_am_i_supplied);
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dev_dbg(psy->dev, "%s %d\n", __func__, error);
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return error;
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}
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EXPORT_SYMBOL_GPL(power_supply_am_i_supplied);
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static int __power_supply_is_system_supplied(struct device *dev, void *data)
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{
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union power_supply_propval ret = {0,};
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struct power_supply *psy = dev_get_drvdata(dev);
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if (psy->type != POWER_SUPPLY_TYPE_BATTERY) {
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if (psy->get_property(psy, POWER_SUPPLY_PROP_ONLINE, &ret))
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return 0;
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if (ret.intval)
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return ret.intval;
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}
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return 0;
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}
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int power_supply_is_system_supplied(void)
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{
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int error;
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error = class_for_each_device(power_supply_class, NULL, NULL,
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__power_supply_is_system_supplied);
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return error;
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}
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EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);
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int power_supply_set_battery_charged(struct power_supply *psy)
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{
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if (psy->type == POWER_SUPPLY_TYPE_BATTERY && psy->set_charged) {
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psy->set_charged(psy);
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return 0;
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}
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return -EINVAL;
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}
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EXPORT_SYMBOL_GPL(power_supply_set_battery_charged);
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static int power_supply_match_device_by_name(struct device *dev, void *data)
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{
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const char *name = data;
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struct power_supply *psy = dev_get_drvdata(dev);
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return strcmp(psy->name, name) == 0;
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}
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struct power_supply *power_supply_get_by_name(char *name)
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{
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struct device *dev = class_find_device(power_supply_class, NULL, name,
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power_supply_match_device_by_name);
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return dev ? dev_get_drvdata(dev) : NULL;
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}
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EXPORT_SYMBOL_GPL(power_supply_get_by_name);
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static void power_supply_dev_release(struct device *dev)
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{
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pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
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kfree(dev);
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}
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int power_supply_register(struct device *parent, struct power_supply *psy)
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{
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struct device *dev;
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int rc;
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dev = kzalloc(sizeof(*dev), GFP_KERNEL);
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if (!dev)
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return -ENOMEM;
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device_initialize(dev);
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dev->class = power_supply_class;
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dev->type = &power_supply_dev_type;
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dev->parent = parent;
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dev->release = power_supply_dev_release;
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dev_set_drvdata(dev, psy);
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psy->dev = dev;
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INIT_WORK(&psy->changed_work, power_supply_changed_work);
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rc = kobject_set_name(&dev->kobj, "%s", psy->name);
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if (rc)
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goto kobject_set_name_failed;
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rc = device_add(dev);
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if (rc)
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goto device_add_failed;
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rc = power_supply_create_triggers(psy);
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if (rc)
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goto create_triggers_failed;
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power_supply_changed(psy);
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goto success;
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create_triggers_failed:
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device_del(dev);
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kobject_set_name_failed:
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device_add_failed:
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put_device(dev);
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success:
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return rc;
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}
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EXPORT_SYMBOL_GPL(power_supply_register);
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void power_supply_unregister(struct power_supply *psy)
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{
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cancel_work_sync(&psy->changed_work);
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power_supply_remove_triggers(psy);
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device_unregister(psy->dev);
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}
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EXPORT_SYMBOL_GPL(power_supply_unregister);
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static int __init power_supply_class_init(void)
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{
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power_supply_class = class_create(THIS_MODULE, "power_supply");
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if (IS_ERR(power_supply_class))
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return PTR_ERR(power_supply_class);
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power_supply_class->dev_uevent = power_supply_uevent;
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power_supply_init_attrs(&power_supply_dev_type);
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return 0;
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}
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static void __exit power_supply_class_exit(void)
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{
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class_destroy(power_supply_class);
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}
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subsys_initcall(power_supply_class_init);
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module_exit(power_supply_class_exit);
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MODULE_DESCRIPTION("Universal power supply monitor class");
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MODULE_AUTHOR("Ian Molton <spyro@f2s.com>, "
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"Szabolcs Gyurko, "
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"Anton Vorontsov <cbou@mail.ru>");
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MODULE_LICENSE("GPL");
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