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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 | ||
b2e8fb6e PZ |
8 | int bdi_init(struct backing_dev_info *bdi) |
9 | { | |
4b01a0b1 | 10 | int i; |
b2e8fb6e PZ |
11 | int err; |
12 | ||
13 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { | |
14 | err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0); | |
04fbfdc1 PZ |
15 | if (err) |
16 | goto err; | |
17 | } | |
18 | ||
19 | bdi->dirty_exceeded = 0; | |
20 | err = prop_local_init_percpu(&bdi->completions); | |
21 | ||
22 | if (err) { | |
23 | err: | |
4b01a0b1 | 24 | while (i--) |
04fbfdc1 | 25 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
b2e8fb6e PZ |
26 | } |
27 | ||
28 | return err; | |
29 | } | |
30 | EXPORT_SYMBOL(bdi_init); | |
31 | ||
32 | void bdi_destroy(struct backing_dev_info *bdi) | |
33 | { | |
34 | int i; | |
35 | ||
36 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) | |
37 | percpu_counter_destroy(&bdi->bdi_stat[i]); | |
04fbfdc1 PZ |
38 | |
39 | prop_local_destroy_percpu(&bdi->completions); | |
b2e8fb6e PZ |
40 | } |
41 | EXPORT_SYMBOL(bdi_destroy); | |
42 | ||
3fcfab16 AM |
43 | static wait_queue_head_t congestion_wqh[2] = { |
44 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), | |
45 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) | |
46 | }; | |
47 | ||
48 | ||
49 | void clear_bdi_congested(struct backing_dev_info *bdi, int rw) | |
50 | { | |
51 | enum bdi_state bit; | |
52 | wait_queue_head_t *wqh = &congestion_wqh[rw]; | |
53 | ||
54 | bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; | |
55 | clear_bit(bit, &bdi->state); | |
56 | smp_mb__after_clear_bit(); | |
57 | if (waitqueue_active(wqh)) | |
58 | wake_up(wqh); | |
59 | } | |
60 | EXPORT_SYMBOL(clear_bdi_congested); | |
61 | ||
62 | void set_bdi_congested(struct backing_dev_info *bdi, int rw) | |
63 | { | |
64 | enum bdi_state bit; | |
65 | ||
66 | bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; | |
67 | set_bit(bit, &bdi->state); | |
68 | } | |
69 | EXPORT_SYMBOL(set_bdi_congested); | |
70 | ||
71 | /** | |
72 | * congestion_wait - wait for a backing_dev to become uncongested | |
73 | * @rw: READ or WRITE | |
74 | * @timeout: timeout in jiffies | |
75 | * | |
76 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit | |
77 | * write congestion. If no backing_devs are congested then just wait for the | |
78 | * next write to be completed. | |
79 | */ | |
80 | long congestion_wait(int rw, long timeout) | |
81 | { | |
82 | long ret; | |
83 | DEFINE_WAIT(wait); | |
84 | wait_queue_head_t *wqh = &congestion_wqh[rw]; | |
85 | ||
86 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
87 | ret = io_schedule_timeout(timeout); | |
88 | finish_wait(wqh, &wait); | |
89 | return ret; | |
90 | } | |
91 | EXPORT_SYMBOL(congestion_wait); | |
04fbfdc1 | 92 |