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3fcfab16 AM |
1 | |
2 | #include <linux/wait.h> | |
3 | #include <linux/backing-dev.h> | |
4 | #include <linux/fs.h> | |
5 | #include <linux/sched.h> | |
6 | #include <linux/module.h> | |
7 | ||
8 | static wait_queue_head_t congestion_wqh[2] = { | |
9 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), | |
10 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) | |
11 | }; | |
12 | ||
13 | ||
14 | void clear_bdi_congested(struct backing_dev_info *bdi, int rw) | |
15 | { | |
16 | enum bdi_state bit; | |
17 | wait_queue_head_t *wqh = &congestion_wqh[rw]; | |
18 | ||
19 | bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; | |
20 | clear_bit(bit, &bdi->state); | |
21 | smp_mb__after_clear_bit(); | |
22 | if (waitqueue_active(wqh)) | |
23 | wake_up(wqh); | |
24 | } | |
25 | EXPORT_SYMBOL(clear_bdi_congested); | |
26 | ||
27 | void set_bdi_congested(struct backing_dev_info *bdi, int rw) | |
28 | { | |
29 | enum bdi_state bit; | |
30 | ||
31 | bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; | |
32 | set_bit(bit, &bdi->state); | |
33 | } | |
34 | EXPORT_SYMBOL(set_bdi_congested); | |
35 | ||
36 | /** | |
37 | * congestion_wait - wait for a backing_dev to become uncongested | |
38 | * @rw: READ or WRITE | |
39 | * @timeout: timeout in jiffies | |
40 | * | |
41 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit | |
42 | * write congestion. If no backing_devs are congested then just wait for the | |
43 | * next write to be completed. | |
44 | */ | |
45 | long congestion_wait(int rw, long timeout) | |
46 | { | |
47 | long ret; | |
48 | DEFINE_WAIT(wait); | |
49 | wait_queue_head_t *wqh = &congestion_wqh[rw]; | |
50 | ||
51 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
52 | ret = io_schedule_timeout(timeout); | |
53 | finish_wait(wqh, &wait); | |
54 | return ret; | |
55 | } | |
56 | EXPORT_SYMBOL(congestion_wait); | |
57 | ||
89a09141 PZ |
58 | long congestion_wait_interruptible(int rw, long timeout) |
59 | { | |
60 | long ret; | |
61 | DEFINE_WAIT(wait); | |
62 | wait_queue_head_t *wqh = &congestion_wqh[rw]; | |
63 | ||
64 | prepare_to_wait(wqh, &wait, TASK_INTERRUPTIBLE); | |
65 | if (signal_pending(current)) | |
66 | ret = -ERESTARTSYS; | |
67 | else | |
68 | ret = io_schedule_timeout(timeout); | |
69 | finish_wait(wqh, &wait); | |
70 | return ret; | |
71 | } | |
72 | EXPORT_SYMBOL(congestion_wait_interruptible); | |
73 | ||
3fcfab16 AM |
74 | /** |
75 | * congestion_end - wake up sleepers on a congested backing_dev_info | |
76 | * @rw: READ or WRITE | |
77 | */ | |
78 | void congestion_end(int rw) | |
79 | { | |
80 | wait_queue_head_t *wqh = &congestion_wqh[rw]; | |
81 | ||
82 | if (waitqueue_active(wqh)) | |
83 | wake_up(wqh); | |
84 | } | |
85 | EXPORT_SYMBOL(congestion_end); |