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1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
7cedffec | 3 | #include <linux/blk-mq.h> |
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4 | #include <linux/blk-pm.h> |
5 | #include <linux/blkdev.h> | |
6 | #include <linux/pm_runtime.h> | |
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7 | #include "blk-mq.h" |
8 | #include "blk-mq-tag.h" | |
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9 | |
10 | /** | |
11 | * blk_pm_runtime_init - Block layer runtime PM initialization routine | |
12 | * @q: the queue of the device | |
13 | * @dev: the device the queue belongs to | |
14 | * | |
15 | * Description: | |
16 | * Initialize runtime-PM-related fields for @q and start auto suspend for | |
17 | * @dev. Drivers that want to take advantage of request-based runtime PM | |
18 | * should call this function after @dev has been initialized, and its | |
19 | * request queue @q has been allocated, and runtime PM for it can not happen | |
20 | * yet(either due to disabled/forbidden or its usage_count > 0). In most | |
21 | * cases, driver should call this function before any I/O has taken place. | |
22 | * | |
23 | * This function takes care of setting up using auto suspend for the device, | |
24 | * the autosuspend delay is set to -1 to make runtime suspend impossible | |
25 | * until an updated value is either set by user or by driver. Drivers do | |
26 | * not need to touch other autosuspend settings. | |
27 | * | |
28 | * The block layer runtime PM is request based, so only works for drivers | |
29 | * that use request as their IO unit instead of those directly use bio's. | |
30 | */ | |
31 | void blk_pm_runtime_init(struct request_queue *q, struct device *dev) | |
32 | { | |
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33 | q->dev = dev; |
34 | q->rpm_status = RPM_ACTIVE; | |
35 | pm_runtime_set_autosuspend_delay(q->dev, -1); | |
36 | pm_runtime_use_autosuspend(q->dev); | |
37 | } | |
38 | EXPORT_SYMBOL(blk_pm_runtime_init); | |
39 | ||
40 | /** | |
41 | * blk_pre_runtime_suspend - Pre runtime suspend check | |
42 | * @q: the queue of the device | |
43 | * | |
44 | * Description: | |
45 | * This function will check if runtime suspend is allowed for the device | |
46 | * by examining if there are any requests pending in the queue. If there | |
47 | * are requests pending, the device can not be runtime suspended; otherwise, | |
48 | * the queue's status will be updated to SUSPENDING and the driver can | |
49 | * proceed to suspend the device. | |
50 | * | |
51 | * For the not allowed case, we mark last busy for the device so that | |
52 | * runtime PM core will try to autosuspend it some time later. | |
53 | * | |
54 | * This function should be called near the start of the device's | |
55 | * runtime_suspend callback. | |
56 | * | |
57 | * Return: | |
58 | * 0 - OK to runtime suspend the device | |
59 | * -EBUSY - Device should not be runtime suspended | |
60 | */ | |
61 | int blk_pre_runtime_suspend(struct request_queue *q) | |
62 | { | |
63 | int ret = 0; | |
64 | ||
65 | if (!q->dev) | |
66 | return ret; | |
67 | ||
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68 | WARN_ON_ONCE(q->rpm_status != RPM_ACTIVE); |
69 | ||
70 | /* | |
71 | * Increase the pm_only counter before checking whether any | |
72 | * non-PM blk_queue_enter() calls are in progress to avoid that any | |
73 | * new non-PM blk_queue_enter() calls succeed before the pm_only | |
74 | * counter is decreased again. | |
75 | */ | |
76 | blk_set_pm_only(q); | |
77 | ret = -EBUSY; | |
78 | /* Switch q_usage_counter from per-cpu to atomic mode. */ | |
79 | blk_freeze_queue_start(q); | |
80 | /* | |
81 | * Wait until atomic mode has been reached. Since that | |
82 | * involves calling call_rcu(), it is guaranteed that later | |
83 | * blk_queue_enter() calls see the pm-only state. See also | |
84 | * http://lwn.net/Articles/573497/. | |
85 | */ | |
86 | percpu_ref_switch_to_atomic_sync(&q->q_usage_counter); | |
87 | if (percpu_ref_is_zero(&q->q_usage_counter)) | |
88 | ret = 0; | |
89 | /* Switch q_usage_counter back to per-cpu mode. */ | |
90 | blk_mq_unfreeze_queue(q); | |
91 | ||
0d945c1f | 92 | spin_lock_irq(&q->queue_lock); |
7cedffec | 93 | if (ret < 0) |
bca6b067 | 94 | pm_runtime_mark_last_busy(q->dev); |
7cedffec | 95 | else |
bca6b067 | 96 | q->rpm_status = RPM_SUSPENDING; |
0d945c1f | 97 | spin_unlock_irq(&q->queue_lock); |
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98 | |
99 | if (ret) | |
100 | blk_clear_pm_only(q); | |
101 | ||
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102 | return ret; |
103 | } | |
104 | EXPORT_SYMBOL(blk_pre_runtime_suspend); | |
105 | ||
106 | /** | |
107 | * blk_post_runtime_suspend - Post runtime suspend processing | |
108 | * @q: the queue of the device | |
109 | * @err: return value of the device's runtime_suspend function | |
110 | * | |
111 | * Description: | |
112 | * Update the queue's runtime status according to the return value of the | |
113 | * device's runtime suspend function and mark last busy for the device so | |
114 | * that PM core will try to auto suspend the device at a later time. | |
115 | * | |
116 | * This function should be called near the end of the device's | |
117 | * runtime_suspend callback. | |
118 | */ | |
119 | void blk_post_runtime_suspend(struct request_queue *q, int err) | |
120 | { | |
121 | if (!q->dev) | |
122 | return; | |
123 | ||
0d945c1f | 124 | spin_lock_irq(&q->queue_lock); |
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125 | if (!err) { |
126 | q->rpm_status = RPM_SUSPENDED; | |
127 | } else { | |
128 | q->rpm_status = RPM_ACTIVE; | |
129 | pm_runtime_mark_last_busy(q->dev); | |
130 | } | |
0d945c1f | 131 | spin_unlock_irq(&q->queue_lock); |
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132 | |
133 | if (err) | |
134 | blk_clear_pm_only(q); | |
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135 | } |
136 | EXPORT_SYMBOL(blk_post_runtime_suspend); | |
137 | ||
138 | /** | |
139 | * blk_pre_runtime_resume - Pre runtime resume processing | |
140 | * @q: the queue of the device | |
141 | * | |
142 | * Description: | |
143 | * Update the queue's runtime status to RESUMING in preparation for the | |
144 | * runtime resume of the device. | |
145 | * | |
146 | * This function should be called near the start of the device's | |
147 | * runtime_resume callback. | |
148 | */ | |
149 | void blk_pre_runtime_resume(struct request_queue *q) | |
150 | { | |
151 | if (!q->dev) | |
152 | return; | |
153 | ||
0d945c1f | 154 | spin_lock_irq(&q->queue_lock); |
bca6b067 | 155 | q->rpm_status = RPM_RESUMING; |
0d945c1f | 156 | spin_unlock_irq(&q->queue_lock); |
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157 | } |
158 | EXPORT_SYMBOL(blk_pre_runtime_resume); | |
159 | ||
160 | /** | |
161 | * blk_post_runtime_resume - Post runtime resume processing | |
162 | * @q: the queue of the device | |
163 | * @err: return value of the device's runtime_resume function | |
164 | * | |
165 | * Description: | |
166 | * Update the queue's runtime status according to the return value of the | |
167 | * device's runtime_resume function. If it is successfully resumed, process | |
168 | * the requests that are queued into the device's queue when it is resuming | |
169 | * and then mark last busy and initiate autosuspend for it. | |
170 | * | |
171 | * This function should be called near the end of the device's | |
172 | * runtime_resume callback. | |
173 | */ | |
174 | void blk_post_runtime_resume(struct request_queue *q, int err) | |
175 | { | |
176 | if (!q->dev) | |
177 | return; | |
178 | ||
0d945c1f | 179 | spin_lock_irq(&q->queue_lock); |
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180 | if (!err) { |
181 | q->rpm_status = RPM_ACTIVE; | |
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182 | pm_runtime_mark_last_busy(q->dev); |
183 | pm_request_autosuspend(q->dev); | |
184 | } else { | |
185 | q->rpm_status = RPM_SUSPENDED; | |
186 | } | |
0d945c1f | 187 | spin_unlock_irq(&q->queue_lock); |
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188 | |
189 | if (!err) | |
190 | blk_clear_pm_only(q); | |
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191 | } |
192 | EXPORT_SYMBOL(blk_post_runtime_resume); | |
193 | ||
194 | /** | |
195 | * blk_set_runtime_active - Force runtime status of the queue to be active | |
196 | * @q: the queue of the device | |
197 | * | |
198 | * If the device is left runtime suspended during system suspend the resume | |
199 | * hook typically resumes the device and corrects runtime status | |
200 | * accordingly. However, that does not affect the queue runtime PM status | |
201 | * which is still "suspended". This prevents processing requests from the | |
202 | * queue. | |
203 | * | |
204 | * This function can be used in driver's resume hook to correct queue | |
205 | * runtime PM status and re-enable peeking requests from the queue. It | |
206 | * should be called before first request is added to the queue. | |
207 | */ | |
208 | void blk_set_runtime_active(struct request_queue *q) | |
209 | { | |
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210 | if (q->dev) { |
211 | spin_lock_irq(&q->queue_lock); | |
212 | q->rpm_status = RPM_ACTIVE; | |
213 | pm_runtime_mark_last_busy(q->dev); | |
214 | pm_request_autosuspend(q->dev); | |
215 | spin_unlock_irq(&q->queue_lock); | |
216 | } | |
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217 | } |
218 | EXPORT_SYMBOL(blk_set_runtime_active); |