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13b35686 PZI |
1 | #ifndef _LINUX_SWAIT_H |
2 | #define _LINUX_SWAIT_H | |
3 | ||
4 | #include <linux/list.h> | |
5 | #include <linux/stddef.h> | |
6 | #include <linux/spinlock.h> | |
7 | #include <asm/current.h> | |
8 | ||
9 | /* | |
10 | * Simple wait queues | |
11 | * | |
12 | * While these are very similar to the other/complex wait queues (wait.h) the | |
13 | * most important difference is that the simple waitqueue allows for | |
14 | * deterministic behaviour -- IOW it has strictly bounded IRQ and lock hold | |
15 | * times. | |
16 | * | |
17 | * In order to make this so, we had to drop a fair number of features of the | |
18 | * other waitqueue code; notably: | |
19 | * | |
20 | * - mixing INTERRUPTIBLE and UNINTERRUPTIBLE sleeps on the same waitqueue; | |
21 | * all wakeups are TASK_NORMAL in order to avoid O(n) lookups for the right | |
22 | * sleeper state. | |
23 | * | |
24 | * - the exclusive mode; because this requires preserving the list order | |
25 | * and this is hard. | |
26 | * | |
27 | * - custom wake functions; because you cannot give any guarantees about | |
28 | * random code. | |
29 | * | |
30 | * As a side effect of this; the data structures are slimmer. | |
31 | * | |
32 | * One would recommend using this wait queue where possible. | |
33 | */ | |
34 | ||
35 | struct task_struct; | |
36 | ||
37 | struct swait_queue_head { | |
38 | raw_spinlock_t lock; | |
39 | struct list_head task_list; | |
40 | }; | |
41 | ||
42 | struct swait_queue { | |
43 | struct task_struct *task; | |
44 | struct list_head task_list; | |
45 | }; | |
46 | ||
47 | #define __SWAITQUEUE_INITIALIZER(name) { \ | |
48 | .task = current, \ | |
49 | .task_list = LIST_HEAD_INIT((name).task_list), \ | |
50 | } | |
51 | ||
52 | #define DECLARE_SWAITQUEUE(name) \ | |
53 | struct swait_queue name = __SWAITQUEUE_INITIALIZER(name) | |
54 | ||
55 | #define __SWAIT_QUEUE_HEAD_INITIALIZER(name) { \ | |
56 | .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \ | |
57 | .task_list = LIST_HEAD_INIT((name).task_list), \ | |
58 | } | |
59 | ||
60 | #define DECLARE_SWAIT_QUEUE_HEAD(name) \ | |
61 | struct swait_queue_head name = __SWAIT_QUEUE_HEAD_INITIALIZER(name) | |
62 | ||
63 | extern void __init_swait_queue_head(struct swait_queue_head *q, const char *name, | |
64 | struct lock_class_key *key); | |
65 | ||
66 | #define init_swait_queue_head(q) \ | |
67 | do { \ | |
68 | static struct lock_class_key __key; \ | |
69 | __init_swait_queue_head((q), #q, &__key); \ | |
70 | } while (0) | |
71 | ||
72 | #ifdef CONFIG_LOCKDEP | |
73 | # define __SWAIT_QUEUE_HEAD_INIT_ONSTACK(name) \ | |
74 | ({ init_swait_queue_head(&name); name; }) | |
75 | # define DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(name) \ | |
76 | struct swait_queue_head name = __SWAIT_QUEUE_HEAD_INIT_ONSTACK(name) | |
77 | #else | |
78 | # define DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(name) \ | |
79 | DECLARE_SWAIT_QUEUE_HEAD(name) | |
80 | #endif | |
81 | ||
82 | static inline int swait_active(struct swait_queue_head *q) | |
83 | { | |
84 | return !list_empty(&q->task_list); | |
85 | } | |
86 | ||
87 | extern void swake_up(struct swait_queue_head *q); | |
88 | extern void swake_up_all(struct swait_queue_head *q); | |
89 | extern void swake_up_locked(struct swait_queue_head *q); | |
90 | ||
91 | extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait); | |
92 | extern void prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait, int state); | |
93 | extern long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state); | |
94 | ||
95 | extern void __finish_swait(struct swait_queue_head *q, struct swait_queue *wait); | |
96 | extern void finish_swait(struct swait_queue_head *q, struct swait_queue *wait); | |
97 | ||
98 | /* as per ___wait_event() but for swait, therefore "exclusive == 0" */ | |
99 | #define ___swait_event(wq, condition, state, ret, cmd) \ | |
100 | ({ \ | |
101 | struct swait_queue __wait; \ | |
102 | long __ret = ret; \ | |
103 | \ | |
104 | INIT_LIST_HEAD(&__wait.task_list); \ | |
105 | for (;;) { \ | |
106 | long __int = prepare_to_swait_event(&wq, &__wait, state);\ | |
107 | \ | |
108 | if (condition) \ | |
109 | break; \ | |
110 | \ | |
111 | if (___wait_is_interruptible(state) && __int) { \ | |
112 | __ret = __int; \ | |
113 | break; \ | |
114 | } \ | |
115 | \ | |
116 | cmd; \ | |
117 | } \ | |
118 | finish_swait(&wq, &__wait); \ | |
119 | __ret; \ | |
120 | }) | |
121 | ||
122 | #define __swait_event(wq, condition) \ | |
123 | (void)___swait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, \ | |
124 | schedule()) | |
125 | ||
126 | #define swait_event(wq, condition) \ | |
127 | do { \ | |
128 | if (condition) \ | |
129 | break; \ | |
130 | __swait_event(wq, condition); \ | |
131 | } while (0) | |
132 | ||
133 | #define __swait_event_timeout(wq, condition, timeout) \ | |
134 | ___swait_event(wq, ___wait_cond_timeout(condition), \ | |
135 | TASK_UNINTERRUPTIBLE, timeout, \ | |
136 | __ret = schedule_timeout(__ret)) | |
137 | ||
138 | #define swait_event_timeout(wq, condition, timeout) \ | |
139 | ({ \ | |
140 | long __ret = timeout; \ | |
141 | if (!___wait_cond_timeout(condition)) \ | |
142 | __ret = __swait_event_timeout(wq, condition, timeout); \ | |
143 | __ret; \ | |
144 | }) | |
145 | ||
146 | #define __swait_event_interruptible(wq, condition) \ | |
147 | ___swait_event(wq, condition, TASK_INTERRUPTIBLE, 0, \ | |
148 | schedule()) | |
149 | ||
150 | #define swait_event_interruptible(wq, condition) \ | |
151 | ({ \ | |
152 | int __ret = 0; \ | |
153 | if (!(condition)) \ | |
154 | __ret = __swait_event_interruptible(wq, condition); \ | |
155 | __ret; \ | |
156 | }) | |
157 | ||
158 | #define __swait_event_interruptible_timeout(wq, condition, timeout) \ | |
159 | ___swait_event(wq, ___wait_cond_timeout(condition), \ | |
160 | TASK_INTERRUPTIBLE, timeout, \ | |
161 | __ret = schedule_timeout(__ret)) | |
162 | ||
163 | #define swait_event_interruptible_timeout(wq, condition, timeout) \ | |
164 | ({ \ | |
165 | long __ret = timeout; \ | |
166 | if (!___wait_cond_timeout(condition)) \ | |
167 | __ret = __swait_event_interruptible_timeout(wq, \ | |
168 | condition, timeout); \ | |
169 | __ret; \ | |
170 | }) | |
171 | ||
172 | #endif /* _LINUX_SWAIT_H */ |