// 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_nomemrestore(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);
