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07fe7cb7 DH |
1 | /* Worker thread pool for slow items, such as filesystem lookups or mkdirs |
2 | * | |
3 | * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public Licence | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the Licence, or (at your option) any later version. | |
8f0aa2f2 DH |
10 | * |
11 | * See Documentation/slow-work.txt | |
07fe7cb7 DH |
12 | */ |
13 | ||
14 | #ifndef _LINUX_SLOW_WORK_H | |
15 | #define _LINUX_SLOW_WORK_H | |
16 | ||
17 | #ifdef CONFIG_SLOW_WORK | |
18 | ||
12e22c5e | 19 | #include <linux/sysctl.h> |
6b8268b1 | 20 | #include <linux/timer.h> |
12e22c5e | 21 | |
07fe7cb7 | 22 | struct slow_work; |
f13a48bd | 23 | #ifdef CONFIG_SLOW_WORK_DEBUG |
8fba10a4 DH |
24 | struct seq_file; |
25 | #endif | |
07fe7cb7 DH |
26 | |
27 | /* | |
28 | * The operations used to support slow work items | |
29 | */ | |
30 | struct slow_work_ops { | |
3d7a641e DH |
31 | /* owner */ |
32 | struct module *owner; | |
33 | ||
07fe7cb7 DH |
34 | /* get a ref on a work item |
35 | * - return 0 if successful, -ve if not | |
36 | */ | |
37 | int (*get_ref)(struct slow_work *work); | |
38 | ||
39 | /* discard a ref to a work item */ | |
40 | void (*put_ref)(struct slow_work *work); | |
41 | ||
42 | /* execute a work item */ | |
43 | void (*execute)(struct slow_work *work); | |
8fba10a4 | 44 | |
f13a48bd DH |
45 | #ifdef CONFIG_SLOW_WORK_DEBUG |
46 | /* describe a work item for debugfs */ | |
8fba10a4 DH |
47 | void (*desc)(struct slow_work *work, struct seq_file *m); |
48 | #endif | |
07fe7cb7 DH |
49 | }; |
50 | ||
51 | /* | |
52 | * A slow work item | |
53 | * - A reference is held on the parent object by the thread pool when it is | |
54 | * queued | |
55 | */ | |
56 | struct slow_work { | |
3d7a641e | 57 | struct module *owner; /* the owning module */ |
07fe7cb7 DH |
58 | unsigned long flags; |
59 | #define SLOW_WORK_PENDING 0 /* item pending (further) execution */ | |
60 | #define SLOW_WORK_EXECUTING 1 /* item currently executing */ | |
61 | #define SLOW_WORK_ENQ_DEFERRED 2 /* item enqueue deferred */ | |
62 | #define SLOW_WORK_VERY_SLOW 3 /* item is very slow */ | |
01609502 | 63 | #define SLOW_WORK_CANCELLING 4 /* item is being cancelled, don't enqueue */ |
6b8268b1 | 64 | #define SLOW_WORK_DELAYED 5 /* item is struct delayed_slow_work with active timer */ |
07fe7cb7 DH |
65 | const struct slow_work_ops *ops; /* operations table for this item */ |
66 | struct list_head link; /* link in queue */ | |
f13a48bd | 67 | #ifdef CONFIG_SLOW_WORK_DEBUG |
8fba10a4 DH |
68 | struct timespec mark; /* jiffies at which queued or exec begun */ |
69 | #endif | |
07fe7cb7 DH |
70 | }; |
71 | ||
6b8268b1 JA |
72 | struct delayed_slow_work { |
73 | struct slow_work work; | |
74 | struct timer_list timer; | |
75 | }; | |
76 | ||
07fe7cb7 DH |
77 | /** |
78 | * slow_work_init - Initialise a slow work item | |
79 | * @work: The work item to initialise | |
80 | * @ops: The operations to use to handle the slow work item | |
81 | * | |
82 | * Initialise a slow work item. | |
83 | */ | |
84 | static inline void slow_work_init(struct slow_work *work, | |
85 | const struct slow_work_ops *ops) | |
86 | { | |
87 | work->flags = 0; | |
88 | work->ops = ops; | |
89 | INIT_LIST_HEAD(&work->link); | |
90 | } | |
91 | ||
6b8268b1 JA |
92 | /** |
93 | * slow_work_init - Initialise a delayed slow work item | |
94 | * @work: The work item to initialise | |
95 | * @ops: The operations to use to handle the slow work item | |
96 | * | |
97 | * Initialise a delayed slow work item. | |
98 | */ | |
99 | static inline void delayed_slow_work_init(struct delayed_slow_work *dwork, | |
100 | const struct slow_work_ops *ops) | |
101 | { | |
102 | init_timer(&dwork->timer); | |
103 | slow_work_init(&dwork->work, ops); | |
104 | } | |
105 | ||
07fe7cb7 | 106 | /** |
5dd559f0 | 107 | * vslow_work_init - Initialise a very slow work item |
07fe7cb7 DH |
108 | * @work: The work item to initialise |
109 | * @ops: The operations to use to handle the slow work item | |
110 | * | |
111 | * Initialise a very slow work item. This item will be restricted such that | |
112 | * only a certain number of the pool threads will be able to execute items of | |
113 | * this type. | |
114 | */ | |
115 | static inline void vslow_work_init(struct slow_work *work, | |
116 | const struct slow_work_ops *ops) | |
117 | { | |
118 | work->flags = 1 << SLOW_WORK_VERY_SLOW; | |
119 | work->ops = ops; | |
120 | INIT_LIST_HEAD(&work->link); | |
121 | } | |
122 | ||
31ba99d3 DH |
123 | /** |
124 | * slow_work_is_queued - Determine if a slow work item is on the work queue | |
125 | * work: The work item to test | |
126 | * | |
127 | * Determine if the specified slow-work item is on the work queue. This | |
128 | * returns true if it is actually on the queue. | |
129 | * | |
130 | * If the item is executing and has been marked for requeue when execution | |
131 | * finishes, then false will be returned. | |
132 | * | |
133 | * Anyone wishing to wait for completion of execution can wait on the | |
134 | * SLOW_WORK_EXECUTING bit. | |
135 | */ | |
136 | static inline bool slow_work_is_queued(struct slow_work *work) | |
137 | { | |
138 | unsigned long flags = work->flags; | |
139 | return flags & SLOW_WORK_PENDING && !(flags & SLOW_WORK_EXECUTING); | |
140 | } | |
141 | ||
07fe7cb7 | 142 | extern int slow_work_enqueue(struct slow_work *work); |
01609502 | 143 | extern void slow_work_cancel(struct slow_work *work); |
3d7a641e DH |
144 | extern int slow_work_register_user(struct module *owner); |
145 | extern void slow_work_unregister_user(struct module *owner); | |
07fe7cb7 | 146 | |
6b8268b1 JA |
147 | extern int delayed_slow_work_enqueue(struct delayed_slow_work *dwork, |
148 | unsigned long delay); | |
149 | ||
150 | static inline void delayed_slow_work_cancel(struct delayed_slow_work *dwork) | |
151 | { | |
152 | slow_work_cancel(&dwork->work); | |
153 | } | |
154 | ||
3bde31a4 DH |
155 | extern bool slow_work_sleep_till_thread_needed(struct slow_work *work, |
156 | signed long *_timeout); | |
157 | ||
12e22c5e DH |
158 | #ifdef CONFIG_SYSCTL |
159 | extern ctl_table slow_work_sysctls[]; | |
160 | #endif | |
07fe7cb7 DH |
161 | |
162 | #endif /* CONFIG_SLOW_WORK */ | |
163 | #endif /* _LINUX_SLOW_WORK_H */ |