Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | |
| 3 | #include <linux/blk-pm.h> |
| 4 | #include <linux/blkdev.h> |
| 5 | #include <linux/pm_runtime.h> |
Bart Van Assche | 7cedffe | 2018-09-26 14:01:09 -0700 | [diff] [blame] | 6 | #include "blk-mq.h" |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 7 | |
| 8 | /** |
| 9 | * blk_pm_runtime_init - Block layer runtime PM initialization routine |
| 10 | * @q: the queue of the device |
| 11 | * @dev: the device the queue belongs to |
| 12 | * |
| 13 | * Description: |
| 14 | * Initialize runtime-PM-related fields for @q and start auto suspend for |
| 15 | * @dev. Drivers that want to take advantage of request-based runtime PM |
| 16 | * should call this function after @dev has been initialized, and its |
| 17 | * request queue @q has been allocated, and runtime PM for it can not happen |
| 18 | * yet(either due to disabled/forbidden or its usage_count > 0). In most |
| 19 | * cases, driver should call this function before any I/O has taken place. |
| 20 | * |
| 21 | * This function takes care of setting up using auto suspend for the device, |
| 22 | * the autosuspend delay is set to -1 to make runtime suspend impossible |
| 23 | * until an updated value is either set by user or by driver. Drivers do |
| 24 | * not need to touch other autosuspend settings. |
| 25 | * |
| 26 | * The block layer runtime PM is request based, so only works for drivers |
| 27 | * that use request as their IO unit instead of those directly use bio's. |
| 28 | */ |
| 29 | void blk_pm_runtime_init(struct request_queue *q, struct device *dev) |
| 30 | { |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 31 | q->dev = dev; |
| 32 | q->rpm_status = RPM_ACTIVE; |
| 33 | pm_runtime_set_autosuspend_delay(q->dev, -1); |
| 34 | pm_runtime_use_autosuspend(q->dev); |
| 35 | } |
| 36 | EXPORT_SYMBOL(blk_pm_runtime_init); |
| 37 | |
| 38 | /** |
| 39 | * blk_pre_runtime_suspend - Pre runtime suspend check |
| 40 | * @q: the queue of the device |
| 41 | * |
| 42 | * Description: |
| 43 | * This function will check if runtime suspend is allowed for the device |
| 44 | * by examining if there are any requests pending in the queue. If there |
| 45 | * are requests pending, the device can not be runtime suspended; otherwise, |
| 46 | * the queue's status will be updated to SUSPENDING and the driver can |
| 47 | * proceed to suspend the device. |
| 48 | * |
| 49 | * For the not allowed case, we mark last busy for the device so that |
| 50 | * runtime PM core will try to autosuspend it some time later. |
| 51 | * |
| 52 | * This function should be called near the start of the device's |
| 53 | * runtime_suspend callback. |
| 54 | * |
| 55 | * Return: |
| 56 | * 0 - OK to runtime suspend the device |
| 57 | * -EBUSY - Device should not be runtime suspended |
| 58 | */ |
| 59 | int blk_pre_runtime_suspend(struct request_queue *q) |
| 60 | { |
| 61 | int ret = 0; |
| 62 | |
| 63 | if (!q->dev) |
| 64 | return ret; |
| 65 | |
Bart Van Assche | 7cedffe | 2018-09-26 14:01:09 -0700 | [diff] [blame] | 66 | WARN_ON_ONCE(q->rpm_status != RPM_ACTIVE); |
| 67 | |
Bart Van Assche | fa4d0f1 | 2020-12-08 21:29:44 -0800 | [diff] [blame] | 68 | spin_lock_irq(&q->queue_lock); |
| 69 | q->rpm_status = RPM_SUSPENDING; |
| 70 | spin_unlock_irq(&q->queue_lock); |
| 71 | |
Bart Van Assche | 7cedffe | 2018-09-26 14:01:09 -0700 | [diff] [blame] | 72 | /* |
| 73 | * Increase the pm_only counter before checking whether any |
| 74 | * non-PM blk_queue_enter() calls are in progress to avoid that any |
| 75 | * new non-PM blk_queue_enter() calls succeed before the pm_only |
| 76 | * counter is decreased again. |
| 77 | */ |
| 78 | blk_set_pm_only(q); |
| 79 | ret = -EBUSY; |
| 80 | /* Switch q_usage_counter from per-cpu to atomic mode. */ |
| 81 | blk_freeze_queue_start(q); |
| 82 | /* |
| 83 | * Wait until atomic mode has been reached. Since that |
| 84 | * involves calling call_rcu(), it is guaranteed that later |
| 85 | * blk_queue_enter() calls see the pm-only state. See also |
| 86 | * http://lwn.net/Articles/573497/. |
| 87 | */ |
| 88 | percpu_ref_switch_to_atomic_sync(&q->q_usage_counter); |
| 89 | if (percpu_ref_is_zero(&q->q_usage_counter)) |
| 90 | ret = 0; |
| 91 | /* Switch q_usage_counter back to per-cpu mode. */ |
| 92 | blk_mq_unfreeze_queue(q); |
| 93 | |
Bart Van Assche | fa4d0f1 | 2020-12-08 21:29:44 -0800 | [diff] [blame] | 94 | if (ret < 0) { |
| 95 | spin_lock_irq(&q->queue_lock); |
| 96 | q->rpm_status = RPM_ACTIVE; |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 97 | pm_runtime_mark_last_busy(q->dev); |
Bart Van Assche | fa4d0f1 | 2020-12-08 21:29:44 -0800 | [diff] [blame] | 98 | spin_unlock_irq(&q->queue_lock); |
Bart Van Assche | 7cedffe | 2018-09-26 14:01:09 -0700 | [diff] [blame] | 99 | |
Bart Van Assche | 7cedffe | 2018-09-26 14:01:09 -0700 | [diff] [blame] | 100 | blk_clear_pm_only(q); |
Bart Van Assche | fa4d0f1 | 2020-12-08 21:29:44 -0800 | [diff] [blame] | 101 | } |
Bart Van Assche | 7cedffe | 2018-09-26 14:01:09 -0700 | [diff] [blame] | 102 | |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 103 | return ret; |
| 104 | } |
| 105 | EXPORT_SYMBOL(blk_pre_runtime_suspend); |
| 106 | |
| 107 | /** |
| 108 | * blk_post_runtime_suspend - Post runtime suspend processing |
| 109 | * @q: the queue of the device |
| 110 | * @err: return value of the device's runtime_suspend function |
| 111 | * |
| 112 | * Description: |
| 113 | * Update the queue's runtime status according to the return value of the |
| 114 | * device's runtime suspend function and mark last busy for the device so |
| 115 | * that PM core will try to auto suspend the device at a later time. |
| 116 | * |
| 117 | * This function should be called near the end of the device's |
| 118 | * runtime_suspend callback. |
| 119 | */ |
| 120 | void blk_post_runtime_suspend(struct request_queue *q, int err) |
| 121 | { |
| 122 | if (!q->dev) |
| 123 | return; |
| 124 | |
Christoph Hellwig | 0d945c1 | 2018-11-15 12:17:28 -0700 | [diff] [blame] | 125 | spin_lock_irq(&q->queue_lock); |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 126 | if (!err) { |
| 127 | q->rpm_status = RPM_SUSPENDED; |
| 128 | } else { |
| 129 | q->rpm_status = RPM_ACTIVE; |
| 130 | pm_runtime_mark_last_busy(q->dev); |
| 131 | } |
Christoph Hellwig | 0d945c1 | 2018-11-15 12:17:28 -0700 | [diff] [blame] | 132 | spin_unlock_irq(&q->queue_lock); |
Bart Van Assche | 7cedffe | 2018-09-26 14:01:09 -0700 | [diff] [blame] | 133 | |
| 134 | if (err) |
| 135 | blk_clear_pm_only(q); |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 136 | } |
| 137 | EXPORT_SYMBOL(blk_post_runtime_suspend); |
| 138 | |
| 139 | /** |
| 140 | * blk_pre_runtime_resume - Pre runtime resume processing |
| 141 | * @q: the queue of the device |
| 142 | * |
| 143 | * Description: |
| 144 | * Update the queue's runtime status to RESUMING in preparation for the |
| 145 | * runtime resume of the device. |
| 146 | * |
| 147 | * This function should be called near the start of the device's |
| 148 | * runtime_resume callback. |
| 149 | */ |
| 150 | void blk_pre_runtime_resume(struct request_queue *q) |
| 151 | { |
| 152 | if (!q->dev) |
| 153 | return; |
| 154 | |
Christoph Hellwig | 0d945c1 | 2018-11-15 12:17:28 -0700 | [diff] [blame] | 155 | spin_lock_irq(&q->queue_lock); |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 156 | q->rpm_status = RPM_RESUMING; |
Christoph Hellwig | 0d945c1 | 2018-11-15 12:17:28 -0700 | [diff] [blame] | 157 | spin_unlock_irq(&q->queue_lock); |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 158 | } |
| 159 | EXPORT_SYMBOL(blk_pre_runtime_resume); |
| 160 | |
| 161 | /** |
| 162 | * blk_post_runtime_resume - Post runtime resume processing |
| 163 | * @q: the queue of the device |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 164 | * |
| 165 | * Description: |
Damien Le Moal | c96b817 | 2023-11-20 16:06:11 +0900 | [diff] [blame] | 166 | * Restart the queue of a runtime suspended device. It does this regardless |
| 167 | * of whether the device's runtime-resume succeeded; even if it failed the |
Alan Stern | 6e1fcab | 2021-12-20 19:21:26 +0800 | [diff] [blame] | 168 | * driver or error handler will need to communicate with the device. |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 169 | * |
| 170 | * This function should be called near the end of the device's |
Damien Le Moal | c96b817 | 2023-11-20 16:06:11 +0900 | [diff] [blame] | 171 | * runtime_resume callback to correct queue runtime PM status and re-enable |
| 172 | * peeking requests from the queue. |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 173 | */ |
Alan Stern | 6e1fcab | 2021-12-20 19:21:26 +0800 | [diff] [blame] | 174 | void blk_post_runtime_resume(struct request_queue *q) |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 175 | { |
Alan Stern | 8f38f8e | 2020-07-06 11:14:36 -0400 | [diff] [blame] | 176 | int old_status; |
| 177 | |
| 178 | if (!q->dev) |
| 179 | return; |
| 180 | |
| 181 | spin_lock_irq(&q->queue_lock); |
| 182 | old_status = q->rpm_status; |
| 183 | q->rpm_status = RPM_ACTIVE; |
| 184 | pm_runtime_mark_last_busy(q->dev); |
| 185 | pm_request_autosuspend(q->dev); |
| 186 | spin_unlock_irq(&q->queue_lock); |
| 187 | |
| 188 | if (old_status != RPM_ACTIVE) |
| 189 | blk_clear_pm_only(q); |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 190 | } |
Damien Le Moal | c96b817 | 2023-11-20 16:06:11 +0900 | [diff] [blame] | 191 | EXPORT_SYMBOL(blk_post_runtime_resume); |