217 lines
6.6 KiB
C
217 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/blk-mq.h>
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#include <linux/blk-pm.h>
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#include <linux/blkdev.h>
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#include <linux/pm_runtime.h>
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#include "blk-mq.h"
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#include "blk-mq-tag.h"
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/**
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* blk_pm_runtime_init - Block layer runtime PM initialization routine
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* @q: the queue of the device
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* @dev: the device the queue belongs to
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*
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* Description:
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* Initialize runtime-PM-related fields for @q and start auto suspend for
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* @dev. Drivers that want to take advantage of request-based runtime PM
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* should call this function after @dev has been initialized, and its
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* request queue @q has been allocated, and runtime PM for it can not happen
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* yet(either due to disabled/forbidden or its usage_count > 0). In most
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* cases, driver should call this function before any I/O has taken place.
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*
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* This function takes care of setting up using auto suspend for the device,
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* the autosuspend delay is set to -1 to make runtime suspend impossible
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* until an updated value is either set by user or by driver. Drivers do
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* not need to touch other autosuspend settings.
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*
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* The block layer runtime PM is request based, so only works for drivers
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* that use request as their IO unit instead of those directly use bio's.
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*/
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void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
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{
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q->dev = dev;
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q->rpm_status = RPM_ACTIVE;
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pm_runtime_set_autosuspend_delay(q->dev, -1);
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pm_runtime_use_autosuspend(q->dev);
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}
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EXPORT_SYMBOL(blk_pm_runtime_init);
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/**
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* blk_pre_runtime_suspend - Pre runtime suspend check
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* @q: the queue of the device
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*
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* Description:
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* This function will check if runtime suspend is allowed for the device
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* by examining if there are any requests pending in the queue. If there
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* are requests pending, the device can not be runtime suspended; otherwise,
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* the queue's status will be updated to SUSPENDING and the driver can
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* proceed to suspend the device.
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*
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* For the not allowed case, we mark last busy for the device so that
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* runtime PM core will try to autosuspend it some time later.
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*
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* This function should be called near the start of the device's
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* runtime_suspend callback.
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*
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* Return:
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* 0 - OK to runtime suspend the device
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* -EBUSY - Device should not be runtime suspended
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*/
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int blk_pre_runtime_suspend(struct request_queue *q)
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{
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int ret = 0;
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if (!q->dev)
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return ret;
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WARN_ON_ONCE(q->rpm_status != RPM_ACTIVE);
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/*
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* Increase the pm_only counter before checking whether any
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* non-PM blk_queue_enter() calls are in progress to avoid that any
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* new non-PM blk_queue_enter() calls succeed before the pm_only
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* counter is decreased again.
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*/
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blk_set_pm_only(q);
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ret = -EBUSY;
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/* Switch q_usage_counter from per-cpu to atomic mode. */
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blk_freeze_queue_start(q);
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/*
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* Wait until atomic mode has been reached. Since that
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* involves calling call_rcu(), it is guaranteed that later
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* blk_queue_enter() calls see the pm-only state. See also
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* http://lwn.net/Articles/573497/.
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*/
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percpu_ref_switch_to_atomic_sync(&q->q_usage_counter);
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if (percpu_ref_is_zero(&q->q_usage_counter))
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ret = 0;
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/* Switch q_usage_counter back to per-cpu mode. */
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blk_mq_unfreeze_queue(q);
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spin_lock_irq(q->queue_lock);
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if (ret < 0)
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pm_runtime_mark_last_busy(q->dev);
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else
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q->rpm_status = RPM_SUSPENDING;
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spin_unlock_irq(q->queue_lock);
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if (ret)
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blk_clear_pm_only(q);
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return ret;
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}
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EXPORT_SYMBOL(blk_pre_runtime_suspend);
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/**
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* blk_post_runtime_suspend - Post runtime suspend processing
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* @q: the queue of the device
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* @err: return value of the device's runtime_suspend function
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*
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* Description:
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* Update the queue's runtime status according to the return value of the
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* device's runtime suspend function and mark last busy for the device so
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* that PM core will try to auto suspend the device at a later time.
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*
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* This function should be called near the end of the device's
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* runtime_suspend callback.
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*/
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void blk_post_runtime_suspend(struct request_queue *q, int err)
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{
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if (!q->dev)
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return;
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spin_lock_irq(q->queue_lock);
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if (!err) {
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q->rpm_status = RPM_SUSPENDED;
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} else {
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q->rpm_status = RPM_ACTIVE;
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pm_runtime_mark_last_busy(q->dev);
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}
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spin_unlock_irq(q->queue_lock);
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if (err)
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blk_clear_pm_only(q);
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}
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EXPORT_SYMBOL(blk_post_runtime_suspend);
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/**
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* blk_pre_runtime_resume - Pre runtime resume processing
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* @q: the queue of the device
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*
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* Description:
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* Update the queue's runtime status to RESUMING in preparation for the
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* runtime resume of the device.
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*
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* This function should be called near the start of the device's
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* runtime_resume callback.
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*/
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void blk_pre_runtime_resume(struct request_queue *q)
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{
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if (!q->dev)
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return;
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spin_lock_irq(q->queue_lock);
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q->rpm_status = RPM_RESUMING;
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spin_unlock_irq(q->queue_lock);
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}
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EXPORT_SYMBOL(blk_pre_runtime_resume);
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/**
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* blk_post_runtime_resume - Post runtime resume processing
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* @q: the queue of the device
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* @err: return value of the device's runtime_resume function
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*
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* Description:
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* Update the queue's runtime status according to the return value of the
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* device's runtime_resume function. If it is successfully resumed, process
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* the requests that are queued into the device's queue when it is resuming
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* and then mark last busy and initiate autosuspend for it.
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*
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* This function should be called near the end of the device's
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* runtime_resume callback.
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*/
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void blk_post_runtime_resume(struct request_queue *q, int err)
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{
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if (!q->dev)
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return;
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spin_lock_irq(q->queue_lock);
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if (!err) {
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q->rpm_status = RPM_ACTIVE;
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pm_runtime_mark_last_busy(q->dev);
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pm_request_autosuspend(q->dev);
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} else {
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q->rpm_status = RPM_SUSPENDED;
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}
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spin_unlock_irq(q->queue_lock);
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if (!err)
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blk_clear_pm_only(q);
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}
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EXPORT_SYMBOL(blk_post_runtime_resume);
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/**
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* blk_set_runtime_active - Force runtime status of the queue to be active
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* @q: the queue of the device
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*
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* If the device is left runtime suspended during system suspend the resume
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* hook typically resumes the device and corrects runtime status
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* accordingly. However, that does not affect the queue runtime PM status
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* which is still "suspended". This prevents processing requests from the
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* queue.
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*
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* This function can be used in driver's resume hook to correct queue
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* runtime PM status and re-enable peeking requests from the queue. It
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* should be called before first request is added to the queue.
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*/
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void blk_set_runtime_active(struct request_queue *q)
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{
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spin_lock_irq(q->queue_lock);
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q->rpm_status = RPM_ACTIVE;
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pm_runtime_mark_last_busy(q->dev);
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pm_request_autosuspend(q->dev);
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spin_unlock_irq(q->queue_lock);
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}
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EXPORT_SYMBOL(blk_set_runtime_active);
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