1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
// SPDX-License-Identifier: GPL-2.0
#include <linux/blk-pm.h>
#include <linux/blkdev.h>
#include <linux/pm_runtime.h>
#include "blk-mq.h"
/**
* blk_pm_runtime_init - Block layer runtime PM initialization routine
* @q: the queue of the device
* @dev: the device the queue belongs to
*
* Description:
* Initialize runtime-PM-related fields for @q and start auto suspend for
* @dev. Drivers that want to take advantage of request-based runtime PM
* should call this function after @dev has been initialized, and its
* request queue @q has been allocated, and runtime PM for it can not happen
* yet(either due to disabled/forbidden or its usage_count > 0). In most
* cases, driver should call this function before any I/O has taken place.
*
* This function takes care of setting up using auto suspend for the device,
* the autosuspend delay is set to -1 to make runtime suspend impossible
* until an updated value is either set by user or by driver. Drivers do
* not need to touch other autosuspend settings.
*
* The block layer runtime PM is request based, so only works for drivers
* that use request as their IO unit instead of those directly use bio's.
*/
void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
{
q->dev = dev;
q->rpm_status = RPM_ACTIVE;
pm_runtime_set_autosuspend_delay(q->dev, -1);
pm_runtime_use_autosuspend(q->dev);
}
EXPORT_SYMBOL(blk_pm_runtime_init);
/**
* blk_pre_runtime_suspend - Pre runtime suspend check
* @q: the queue of the device
*
* Description:
* This function will check if runtime suspend is allowed for the device
* by examining if there are any requests pending in the queue. If there
* are requests pending, the device can not be runtime suspended; otherwise,
* the queue's status will be updated to SUSPENDING and the driver can
* proceed to suspend the device.
*
* For the not allowed case, we mark last busy for the device so that
* runtime PM core will try to autosuspend it some time later.
*
* This function should be called near the start of the device's
* runtime_suspend callback.
*
* Return:
* 0 - OK to runtime suspend the device
* -EBUSY - Device should not be runtime suspended
*/
int blk_pre_runtime_suspend(struct request_queue *q)
{
int ret = 0;
if (!q->dev)
return ret;
WARN_ON_ONCE(q->rpm_status != RPM_ACTIVE);
spin_lock_irq(&q->queue_lock);
q->rpm_status = RPM_SUSPENDING;
spin_unlock_irq(&q->queue_lock);
/*
* Increase the pm_only counter before checking whether any
* non-PM blk_queue_enter() calls are in progress to avoid that any
* new non-PM blk_queue_enter() calls succeed before the pm_only
* counter is decreased again.
*/
blk_set_pm_only(q);
ret = -EBUSY;
/* Switch q_usage_counter from per-cpu to atomic mode. */
blk_freeze_queue_start(q);
/*
* Wait until atomic mode has been reached. Since that
* involves calling call_rcu(), it is guaranteed that later
* blk_queue_enter() calls see the pm-only state. See also
* http://lwn.net/Articles/573497/.
*/
percpu_ref_switch_to_atomic_sync(&q->q_usage_counter);
if (percpu_ref_is_zero(&q->q_usage_counter))
ret = 0;
/* Switch q_usage_counter back to per-cpu mode. */
blk_mq_unfreeze_queue(q);
if (ret < 0) {
spin_lock_irq(&q->queue_lock);
q->rpm_status = RPM_ACTIVE;
pm_runtime_mark_last_busy(q->dev);
spin_unlock_irq(&q->queue_lock);
blk_clear_pm_only(q);
}
return ret;
}
EXPORT_SYMBOL(blk_pre_runtime_suspend);
/**
* blk_post_runtime_suspend - Post runtime suspend processing
* @q: the queue of the device
* @err: return value of the device's runtime_suspend function
*
* Description:
* Update the queue's runtime status according to the return value of the
* device's runtime suspend function and mark last busy for the device so
* that PM core will try to auto suspend the device at a later time.
*
* This function should be called near the end of the device's
* runtime_suspend callback.
*/
void blk_post_runtime_suspend(struct request_queue *q, int err)
{
if (!q->dev)
return;
spin_lock_irq(&q->queue_lock);
if (!err) {
q->rpm_status = RPM_SUSPENDED;
} else {
q->rpm_status = RPM_ACTIVE;
pm_runtime_mark_last_busy(q->dev);
}
spin_unlock_irq(&q->queue_lock);
if (err)
blk_clear_pm_only(q);
}
EXPORT_SYMBOL(blk_post_runtime_suspend);
/**
* blk_pre_runtime_resume - Pre runtime resume processing
* @q: the queue of the device
*
* Description:
* Update the queue's runtime status to RESUMING in preparation for the
* runtime resume of the device.
*
* This function should be called near the start of the device's
* runtime_resume callback.
*/
void blk_pre_runtime_resume(struct request_queue *q)
{
if (!q->dev)
return;
spin_lock_irq(&q->queue_lock);
q->rpm_status = RPM_RESUMING;
spin_unlock_irq(&q->queue_lock);
}
EXPORT_SYMBOL(blk_pre_runtime_resume);
/**
* blk_post_runtime_resume - Post runtime resume processing
* @q: the queue of the device
*
* Description:
* Restart the queue of a runtime suspended device. It does this regardless
* of whether the device's runtime-resume succeeded; even if it failed the
* driver or error handler will need to communicate with the device.
*
* This function should be called near the end of the device's
* runtime_resume callback to correct queue runtime PM status and re-enable
* peeking requests from the queue.
*/
void blk_post_runtime_resume(struct request_queue *q)
{
int old_status;
if (!q->dev)
return;
spin_lock_irq(&q->queue_lock);
old_status = q->rpm_status;
q->rpm_status = RPM_ACTIVE;
pm_runtime_mark_last_busy(q->dev);
pm_request_autosuspend(q->dev);
spin_unlock_irq(&q->queue_lock);
if (old_status != RPM_ACTIVE)
blk_clear_pm_only(q);
}
EXPORT_SYMBOL(blk_post_runtime_resume);
|
