1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/blk-mq.h> 4 #include <linux/blk-pm.h> 5 #include <linux/blkdev.h> 6 #include <linux/pm_runtime.h> 7 #include "blk-mq.h" 8 #include "blk-mq-tag.h" 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 { 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 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 92 spin_lock_irq(q->queue_lock); 93 if (ret < 0) 94 pm_runtime_mark_last_busy(q->dev); 95 else 96 q->rpm_status = RPM_SUSPENDING; 97 spin_unlock_irq(q->queue_lock); 98 99 if (ret) 100 blk_clear_pm_only(q); 101 102 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; 123 124 spin_lock_irq(q->queue_lock); 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 } 131 spin_unlock_irq(q->queue_lock); 132 133 if (err) 134 blk_clear_pm_only(q); 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; 153 154 spin_lock_irq(q->queue_lock); 155 q->rpm_status = RPM_RESUMING; 156 spin_unlock_irq(q->queue_lock); 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; 178 179 spin_lock_irq(q->queue_lock); 180 if (!err) { 181 q->rpm_status = RPM_ACTIVE; 182 pm_runtime_mark_last_busy(q->dev); 183 pm_request_autosuspend(q->dev); 184 } else { 185 q->rpm_status = RPM_SUSPENDED; 186 } 187 spin_unlock_irq(q->queue_lock); 188 189 if (!err) 190 blk_clear_pm_only(q); 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 { 210 spin_lock_irq(q->queue_lock); 211 q->rpm_status = RPM_ACTIVE; 212 pm_runtime_mark_last_busy(q->dev); 213 pm_request_autosuspend(q->dev); 214 spin_unlock_irq(q->queue_lock); 215 } 216 EXPORT_SYMBOL(blk_set_runtime_active); 217