Commit | Line | Data |
---|---|---|
13b35686 PZI |
1 | #include <linux/sched.h> |
2 | #include <linux/swait.h> | |
3 | ||
4 | void __init_swait_queue_head(struct swait_queue_head *q, const char *name, | |
5 | struct lock_class_key *key) | |
6 | { | |
7 | raw_spin_lock_init(&q->lock); | |
8 | lockdep_set_class_and_name(&q->lock, key, name); | |
9 | INIT_LIST_HEAD(&q->task_list); | |
10 | } | |
11 | EXPORT_SYMBOL(__init_swait_queue_head); | |
12 | ||
13 | /* | |
14 | * The thing about the wake_up_state() return value; I think we can ignore it. | |
15 | * | |
16 | * If for some reason it would return 0, that means the previously waiting | |
17 | * task is already running, so it will observe condition true (or has already). | |
18 | */ | |
19 | void swake_up_locked(struct swait_queue_head *q) | |
20 | { | |
21 | struct swait_queue *curr; | |
22 | ||
23 | if (list_empty(&q->task_list)) | |
24 | return; | |
25 | ||
26 | curr = list_first_entry(&q->task_list, typeof(*curr), task_list); | |
27 | wake_up_process(curr->task); | |
28 | list_del_init(&curr->task_list); | |
29 | } | |
30 | EXPORT_SYMBOL(swake_up_locked); | |
31 | ||
32 | void swake_up(struct swait_queue_head *q) | |
33 | { | |
34 | unsigned long flags; | |
35 | ||
36 | if (!swait_active(q)) | |
37 | return; | |
38 | ||
39 | raw_spin_lock_irqsave(&q->lock, flags); | |
40 | swake_up_locked(q); | |
41 | raw_spin_unlock_irqrestore(&q->lock, flags); | |
42 | } | |
43 | EXPORT_SYMBOL(swake_up); | |
44 | ||
45 | /* | |
46 | * Does not allow usage from IRQ disabled, since we must be able to | |
47 | * release IRQs to guarantee bounded hold time. | |
48 | */ | |
49 | void swake_up_all(struct swait_queue_head *q) | |
50 | { | |
51 | struct swait_queue *curr; | |
52 | LIST_HEAD(tmp); | |
53 | ||
54 | if (!swait_active(q)) | |
55 | return; | |
56 | ||
57 | raw_spin_lock_irq(&q->lock); | |
58 | list_splice_init(&q->task_list, &tmp); | |
59 | while (!list_empty(&tmp)) { | |
60 | curr = list_first_entry(&tmp, typeof(*curr), task_list); | |
61 | ||
62 | wake_up_state(curr->task, TASK_NORMAL); | |
63 | list_del_init(&curr->task_list); | |
64 | ||
65 | if (list_empty(&tmp)) | |
66 | break; | |
67 | ||
68 | raw_spin_unlock_irq(&q->lock); | |
69 | raw_spin_lock_irq(&q->lock); | |
70 | } | |
71 | raw_spin_unlock_irq(&q->lock); | |
72 | } | |
73 | EXPORT_SYMBOL(swake_up_all); | |
74 | ||
75 | void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait) | |
76 | { | |
77 | wait->task = current; | |
78 | if (list_empty(&wait->task_list)) | |
79 | list_add(&wait->task_list, &q->task_list); | |
80 | } | |
81 | ||
82 | void prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait, int state) | |
83 | { | |
84 | unsigned long flags; | |
85 | ||
86 | raw_spin_lock_irqsave(&q->lock, flags); | |
87 | __prepare_to_swait(q, wait); | |
88 | set_current_state(state); | |
89 | raw_spin_unlock_irqrestore(&q->lock, flags); | |
90 | } | |
91 | EXPORT_SYMBOL(prepare_to_swait); | |
92 | ||
93 | long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state) | |
94 | { | |
95 | if (signal_pending_state(state, current)) | |
96 | return -ERESTARTSYS; | |
97 | ||
98 | prepare_to_swait(q, wait, state); | |
99 | ||
100 | return 0; | |
101 | } | |
102 | EXPORT_SYMBOL(prepare_to_swait_event); | |
103 | ||
104 | void __finish_swait(struct swait_queue_head *q, struct swait_queue *wait) | |
105 | { | |
106 | __set_current_state(TASK_RUNNING); | |
107 | if (!list_empty(&wait->task_list)) | |
108 | list_del_init(&wait->task_list); | |
109 | } | |
110 | ||
111 | void finish_swait(struct swait_queue_head *q, struct swait_queue *wait) | |
112 | { | |
113 | unsigned long flags; | |
114 | ||
115 | __set_current_state(TASK_RUNNING); | |
116 | ||
117 | if (!list_empty_careful(&wait->task_list)) { | |
118 | raw_spin_lock_irqsave(&q->lock, flags); | |
119 | list_del_init(&wait->task_list); | |
120 | raw_spin_unlock_irqrestore(&q->lock, flags); | |
121 | } | |
122 | } | |
123 | EXPORT_SYMBOL(finish_swait); |