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/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef __LINUX_DEVM_HELPERS_H
#define __LINUX_DEVM_HELPERS_H
/*
* Functions which do automatically cancel operations or release resources upon
* driver detach.
*
* These should be helpful to avoid mixing the manual and devm-based resource
* management which can be source of annoying, rarely occurring,
* hard-to-reproduce bugs.
*
* Please take into account that devm based cancellation may be performed some
* time after the remove() is ran.
*
* Thus mixing devm and manual resource management can easily cause problems
* when unwinding operations with dependencies. IRQ scheduling a work in a queue
* is typical example where IRQs are often devm-managed and WQs are manually
* cleaned at remove(). If IRQs are not manually freed at remove() (and this is
* often the case when we use devm for IRQs) we have a period of time after
* remove() - and before devm managed IRQs are freed - where new IRQ may fire
* and schedule a work item which won't be cancelled because remove() was
* already ran.
*/
#include <linux/device.h>
#include <linux/workqueue.h>
static inline void devm_delayed_work_drop(void *res)
{
cancel_delayed_work_sync(res);
}
/**
* devm_delayed_work_autocancel - Resource-managed delayed work allocation
* @dev: Device which lifetime work is bound to
* @w: Work item to be queued
* @worker: Worker function
*
* Initialize delayed work which is automatically cancelled when driver is
* detached. A few drivers need delayed work which must be cancelled before
* driver is detached to avoid accessing removed resources.
* devm_delayed_work_autocancel() can be used to omit the explicit
* cancellation when driver is detached.
*/
static inline int devm_delayed_work_autocancel(struct device *dev,
struct delayed_work *w,
work_func_t worker)
{
INIT_DELAYED_WORK(w, worker);
return devm_add_action(dev, devm_delayed_work_drop, w);
}
static inline void devm_work_drop(void *res)
{
cancel_work_sync(res);
}
/**
* devm_work_autocancel - Resource-managed work allocation
* @dev: Device which lifetime work is bound to
* @w: Work to be added (and automatically cancelled)
* @worker: Worker function
*
* Initialize work which is automatically cancelled when driver is detached.
* A few drivers need to queue work which must be cancelled before driver
* is detached to avoid accessing removed resources.
* devm_work_autocancel() can be used to omit the explicit
* cancellation when driver is detached.
*/
static inline int devm_work_autocancel(struct device *dev,
struct work_struct *w,
work_func_t worker)
{
INIT_WORK(w, worker);
return devm_add_action(dev, devm_work_drop, w);
}
#endif
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