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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 | ||
29 | static inline void devm_delayed_work_drop(void *res) | |
30 | { | |
31 | cancel_delayed_work_sync(res); | |
32 | } | |
33 | ||
34 | /** | |
a943d763 MV |
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 | |
0341ce54 | 39 | * |
a943d763 MV |
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. | |
0341ce54 MV |
43 | * devm_delayed_work_autocancel() can be used to omit the explicit |
44 | * cancelleation when driver is detached. | |
45 | */ | |
46 | static 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 | ||
7a2c4cc5 MV |
54 | static 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 | */ | |
71 | static 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 | ||
0341ce54 | 79 | #endif |