cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

devm-helpers.h (2740B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2#ifndef __LINUX_DEVM_HELPERS_H
      3#define __LINUX_DEVM_HELPERS_H
      4
      5/*
      6 * Functions which do automatically cancel operations or release resources upon
      7 * driver detach.
      8 *
      9 * These should be helpful to avoid mixing the manual and devm-based resource
     10 * management which can be source of annoying, rarely occurring,
     11 * hard-to-reproduce bugs.
     12 *
     13 * Please take into account that devm based cancellation may be performed some
     14 * time after the remove() is ran.
     15 *
     16 * Thus mixing devm and manual resource management can easily cause problems
     17 * when unwinding operations with dependencies. IRQ scheduling a work in a queue
     18 * is typical example where IRQs are often devm-managed and WQs are manually
     19 * cleaned at remove(). If IRQs are not manually freed at remove() (and this is
     20 * often the case when we use devm for IRQs) we have a period of time after
     21 * remove() - and before devm managed IRQs are freed - where new IRQ may fire
     22 * and schedule a work item which won't be cancelled because remove() was
     23 * already ran.
     24 */
     25
     26#include <linux/device.h>
     27#include <linux/workqueue.h>
     28
     29static inline void devm_delayed_work_drop(void *res)
     30{
     31	cancel_delayed_work_sync(res);
     32}
     33
     34/**
     35 * devm_delayed_work_autocancel - Resource-managed delayed work allocation
     36 * @dev:	Device which lifetime work is bound to
     37 * @w:		Work item to be queued
     38 * @worker:	Worker function
     39 *
     40 * Initialize delayed work which is automatically cancelled when driver is
     41 * detached. A few drivers need delayed work which must be cancelled before
     42 * driver is detached to avoid accessing removed resources.
     43 * devm_delayed_work_autocancel() can be used to omit the explicit
     44 * cancelleation when driver is detached.
     45 */
     46static inline int devm_delayed_work_autocancel(struct device *dev,
     47					       struct delayed_work *w,
     48					       work_func_t worker)
     49{
     50	INIT_DELAYED_WORK(w, worker);
     51	return devm_add_action(dev, devm_delayed_work_drop, w);
     52}
     53
     54static inline void devm_work_drop(void *res)
     55{
     56	cancel_work_sync(res);
     57}
     58
     59/**
     60 * devm_work_autocancel - Resource-managed work allocation
     61 * @dev:	Device which lifetime work is bound to
     62 * @w:		Work to be added (and automatically cancelled)
     63 * @worker:	Worker function
     64 *
     65 * Initialize work which is automatically cancelled when driver is detached.
     66 * A few drivers need to queue work which must be cancelled before driver
     67 * is detached to avoid accessing removed resources.
     68 * devm_work_autocancel() can be used to omit the explicit
     69 * cancelleation when driver is detached.
     70 */
     71static inline int devm_work_autocancel(struct device *dev,
     72				       struct work_struct *w,
     73				       work_func_t worker)
     74{
     75	INIT_WORK(w, worker);
     76	return devm_add_action(dev, devm_work_drop, w);
     77}
     78
     79#endif