1 /* SPDX-License-Identifier: GPL-2.0-only */ 1 /* SPDX-License-Identifier: GPL-2.0-only */
2 #ifndef __LINUX_DEVM_HELPERS_H 2 #ifndef __LINUX_DEVM_HELPERS_H
3 #define __LINUX_DEVM_HELPERS_H 3 #define __LINUX_DEVM_HELPERS_H
4 4
5 /* 5 /*
6 * Functions which do automatically cancel ope 6 * Functions which do automatically cancel operations or release resources upon
7 * driver detach. 7 * driver detach.
8 * 8 *
9 * These should be helpful to avoid mixing the 9 * These should be helpful to avoid mixing the manual and devm-based resource
10 * management which can be source of annoying, 10 * management which can be source of annoying, rarely occurring,
11 * hard-to-reproduce bugs. 11 * hard-to-reproduce bugs.
12 * 12 *
13 * Please take into account that devm based ca 13 * Please take into account that devm based cancellation may be performed some
14 * time after the remove() is ran. 14 * time after the remove() is ran.
15 * 15 *
16 * Thus mixing devm and manual resource manage 16 * Thus mixing devm and manual resource management can easily cause problems
17 * when unwinding operations with dependencies 17 * when unwinding operations with dependencies. IRQ scheduling a work in a queue
18 * is typical example where IRQs are often dev 18 * is typical example where IRQs are often devm-managed and WQs are manually
19 * cleaned at remove(). If IRQs are not manual 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) w 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 21 * remove() - and before devm managed IRQs are freed - where new IRQ may fire
22 * and schedule a work item which won't be can 22 * and schedule a work item which won't be cancelled because remove() was
23 * already ran. 23 * already ran.
24 */ 24 */
25 25
26 #include <linux/device.h> 26 #include <linux/device.h>
27 #include <linux/workqueue.h> 27 #include <linux/workqueue.h>
28 28
29 static inline void devm_delayed_work_drop(void 29 static inline void devm_delayed_work_drop(void *res)
30 { 30 {
31 cancel_delayed_work_sync(res); 31 cancel_delayed_work_sync(res);
32 } 32 }
33 33
34 /** 34 /**
35 * devm_delayed_work_autocancel - Resource-man 35 * devm_delayed_work_autocancel - Resource-managed delayed work allocation
36 * @dev: Device which lifetime work is 36 * @dev: Device which lifetime work is bound to
37 * @w: Work item to be queued 37 * @w: Work item to be queued
38 * @worker: Worker function 38 * @worker: Worker function
39 * 39 *
40 * Initialize delayed work which is automatica 40 * Initialize delayed work which is automatically cancelled when driver is
41 * detached. A few drivers need delayed work w 41 * detached. A few drivers need delayed work which must be cancelled before
42 * driver is detached to avoid accessing remov 42 * driver is detached to avoid accessing removed resources.
43 * devm_delayed_work_autocancel() can be used 43 * devm_delayed_work_autocancel() can be used to omit the explicit
44 * cancellation when driver is detached. !! 44 * cancelleation when driver is detached.
45 */ 45 */
46 static inline int devm_delayed_work_autocancel 46 static inline int devm_delayed_work_autocancel(struct device *dev,
47 47 struct delayed_work *w,
48 48 work_func_t worker)
49 { 49 {
50 INIT_DELAYED_WORK(w, worker); 50 INIT_DELAYED_WORK(w, worker);
51 return devm_add_action(dev, devm_delay 51 return devm_add_action(dev, devm_delayed_work_drop, w);
52 } <<
53 <<
54 static inline void devm_work_drop(void *res) <<
55 { <<
56 cancel_work_sync(res); <<
57 } <<
58 <<
59 /** <<
60 * devm_work_autocancel - Resource-managed wor <<
61 * @dev: Device which lifetime work is <<
62 * @w: Work to be added (and automati <<
63 * @worker: Worker function <<
64 * <<
65 * Initialize work which is automatically canc <<
66 * A few drivers need to queue work which must <<
67 * is detached to avoid accessing removed reso <<
68 * devm_work_autocancel() can be used to omit <<
69 * cancellation when driver is detached. <<
70 */ <<
71 static inline int devm_work_autocancel(struct <<
72 struct <<
73 work_fu <<
74 { <<
75 INIT_WORK(w, worker); <<
76 return devm_add_action(dev, devm_work_ <<
77 } 52 }
78 53
79 #endif 54 #endif
80 55
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