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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * drivers/base/power/runtime.c - Helper functions for device runtime PM
  *
  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
  * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
  */
 #include <linux/sched/mm.h>
 #include <linux/ktime.h>
 #include <linux/hrtimer.h>
 #include <linux/export.h>
 #include <linux/pm_runtime.h>
 #include <linux/pm_wakeirq.h>
 #include <trace/events/rpm.h>
 
 #include "../base.h"
 #include "power.h"
 
 typedef int (*pm_callback_t)(struct device *);
 
 static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
 {
     pm_callback_t cb;
     const struct dev_pm_ops *ops;
 
     if (dev->pm_domain)
         ops = &dev->pm_domain->ops;
     else if (dev->type && dev->type->pm)
         ops = dev->type->pm;
     else if (dev->class && dev->class->pm)
         ops = dev->class->pm;
     else if (dev->bus && dev->bus->pm)
         ops = dev->bus->pm;
     else
         ops = NULL;
 
     if (ops)
         cb = *(pm_callback_t *)((void *)ops + cb_offset);
     else
         cb = NULL;
 
     if (!cb && dev->driver && dev->driver->pm)
         cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
 
     return cb;
 }
 
 #define RPM_GET_CALLBACK(dev, callback) \
         __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
 
 static int rpm_resume(struct device *dev, int rpmflags);
 static int rpm_suspend(struct device *dev, int rpmflags);
 
 /**
  * update_pm_runtime_accounting - Update the time accounting of power states
  * @dev: Device to update the accounting for
  *
  * In order to be able to have time accounting of the various power states
  * (as used by programs such as PowerTOP to show the effectiveness of runtime
  * PM), we need to track the time spent in each state.
  * update_pm_runtime_accounting must be called each time before the
  * runtime_status field is updated, to account the time in the old state
  * correctly.
  */
 static void update_pm_runtime_accounting(struct device *dev)
 {
     u64 now, last, delta;
 
     if (dev->power.disable_depth > 0)
         return;
 
     last = dev->power.accounting_timestamp;
 
     now = ktime_get_mono_fast_ns();
     dev->power.accounting_timestamp = now;
 
     /*
      * Because ktime_get_mono_fast_ns() is not monotonic during
      * timekeeping updates, ensure that 'now' is after the last saved
      * timesptamp.
      */
     if (now < last)
         return;
 
     delta = now - last;
 
     if (dev->power.runtime_status == RPM_SUSPENDED)
         dev->power.suspended_time += delta;
     else
         dev->power.active_time += delta;
 }
 
 static void __update_runtime_status(struct device *dev, enum rpm_status status)
 {
     update_pm_runtime_accounting(dev);
     dev->power.runtime_status = status;
 }
 
 static u64 rpm_get_accounted_time(struct device *dev, bool suspended)
 {
     u64 time;
     unsigned long flags;
 
     spin_lock_irqsave(&dev->power.lock, flags);
 
     update_pm_runtime_accounting(dev);
     time = suspended ? dev->power.suspended_time : dev->power.active_time;
 
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     return time;
 }
 
 u64 pm_runtime_active_time(struct device *dev)
 {
     return rpm_get_accounted_time(dev, false);
 }
 
 u64 pm_runtime_suspended_time(struct device *dev)
 {
     return rpm_get_accounted_time(dev, true);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
 
 /**
  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
  * @dev: Device to handle.
  */
 static void pm_runtime_deactivate_timer(struct device *dev)
 {
     if (dev->power.timer_expires > 0) {
         hrtimer_try_to_cancel(&dev->power.suspend_timer);
         dev->power.timer_expires = 0;
     }
 }
 
 /**
  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
  * @dev: Device to handle.
  */
 static void pm_runtime_cancel_pending(struct device *dev)
 {
     pm_runtime_deactivate_timer(dev);
     /*
      * In case there's a request pending, make sure its work function will
      * return without doing anything.
      */
     dev->power.request = RPM_REQ_NONE;
 }
 
 /*
  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
  * @dev: Device to handle.
  *
  * Compute the autosuspend-delay expiration time based on the device's
  * power.last_busy time.  If the delay has already expired or is disabled
  * (negative) or the power.use_autosuspend flag isn't set, return 0.
  * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero).
  *
  * This function may be called either with or without dev->power.lock held.
  * Either way it can be racy, since power.last_busy may be updated at any time.
  */
 u64 pm_runtime_autosuspend_expiration(struct device *dev)
 {
     int autosuspend_delay;
     u64 expires;
 
     if (!dev->power.use_autosuspend)
         return 0;
 
     autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
     if (autosuspend_delay < 0)
         return 0;
 
     expires  = READ_ONCE(dev->power.last_busy);
     expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
     if (expires > ktime_get_mono_fast_ns())
         return expires; /* Expires in the future */
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 
 static int dev_memalloc_noio(struct device *dev, void *data)
 {
     return dev->power.memalloc_noio;
 }
 
 /*
  * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
  * @dev: Device to handle.
  * @enable: True for setting the flag and False for clearing the flag.
  *
  * Set the flag for all devices in the path from the device to the
  * root device in the device tree if @enable is true, otherwise clear
  * the flag for devices in the path whose siblings don't set the flag.
  *
  * The function should only be called by block device, or network
  * device driver for solving the deadlock problem during runtime
  * resume/suspend:
  *
  *     If memory allocation with GFP_KERNEL is called inside runtime
  *     resume/suspend callback of any one of its ancestors(or the
  *     block device itself), the deadlock may be triggered inside the
  *     memory allocation since it might not complete until the block
  *     device becomes active and the involed page I/O finishes. The
  *     situation is pointed out first by Alan Stern. Network device
  *     are involved in iSCSI kind of situation.
  *
  * The lock of dev_hotplug_mutex is held in the function for handling
  * hotplug race because pm_runtime_set_memalloc_noio() may be called
  * in async probe().
  *
  * The function should be called between device_add() and device_del()
  * on the affected device(block/network device).
  */
 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
 {
     static DEFINE_MUTEX(dev_hotplug_mutex);
 
     mutex_lock(&dev_hotplug_mutex);
     for (;;) {
         bool enabled;
 
         /* hold power lock since bitfield is not SMP-safe. */
         spin_lock_irq(&dev->power.lock);
         enabled = dev->power.memalloc_noio;
         dev->power.memalloc_noio = enable;
         spin_unlock_irq(&dev->power.lock);
 
         /*
          * not need to enable ancestors any more if the device
          * has been enabled.
          */
         if (enabled && enable)
             break;
 
         dev = dev->parent;
 
         /*
          * clear flag of the parent device only if all the
          * children don't set the flag because ancestor's
          * flag was set by any one of the descendants.
          */
         if (!dev || (!enable &&
                  device_for_each_child(dev, NULL,
                            dev_memalloc_noio)))
             break;
     }
     mutex_unlock(&dev_hotplug_mutex);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
 
 /**
  * rpm_check_suspend_allowed - Test whether a device may be suspended.
  * @dev: Device to test.
  */
 static int rpm_check_suspend_allowed(struct device *dev)
 {
     int retval = 0;
 
     if (dev->power.runtime_error)
         retval = -EINVAL;
     else if (dev->power.disable_depth > 0)
         retval = -EACCES;
     else if (atomic_read(&dev->power.usage_count))
         retval = -EAGAIN;
     else if (!dev->power.ignore_children &&
             atomic_read(&dev->power.child_count))
         retval = -EBUSY;
 
     /* Pending resume requests take precedence over suspends. */
     else if ((dev->power.deferred_resume
             && dev->power.runtime_status == RPM_SUSPENDING)
         || (dev->power.request_pending
             && dev->power.request == RPM_REQ_RESUME))
         retval = -EAGAIN;
     else if (__dev_pm_qos_resume_latency(dev) == 0)
         retval = -EPERM;
     else if (dev->power.runtime_status == RPM_SUSPENDED)
         retval = 1;
 
     return retval;
 }
 
 static int rpm_get_suppliers(struct device *dev)
 {
     struct device_link *link;
 
     list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
                 device_links_read_lock_held()) {
         int retval;
 
         if (!(link->flags & DL_FLAG_PM_RUNTIME))
             continue;
 
         retval = pm_runtime_get_sync(link->supplier);
         /* Ignore suppliers with disabled runtime PM. */
         if (retval < 0 && retval != -EACCES) {
             pm_runtime_put_noidle(link->supplier);
             return retval;
         }
         refcount_inc(&link->rpm_active);
     }
     return 0;
 }
 
 /**
  * pm_runtime_release_supplier - Drop references to device link's supplier.
  * @link: Target device link.
  *
  * Drop all runtime PM references associated with @link to its supplier device.
  */
 void pm_runtime_release_supplier(struct device_link *link)
 {
     struct device *supplier = link->supplier;
 
     /*
      * The additional power.usage_count check is a safety net in case
      * the rpm_active refcount becomes saturated, in which case
      * refcount_dec_not_one() would return true forever, but it is not
      * strictly necessary.
      */
     while (refcount_dec_not_one(&link->rpm_active) &&
            atomic_read(&supplier->power.usage_count) > 0)
         pm_runtime_put_noidle(supplier);
 }
 
 static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
 {
     struct device_link *link;
 
     list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
                 device_links_read_lock_held()) {
         pm_runtime_release_supplier(link);
         if (try_to_suspend)
             pm_request_idle(link->supplier);
     }
 }
 
 static void rpm_put_suppliers(struct device *dev)
 {
     __rpm_put_suppliers(dev, true);
 }
 
 static void rpm_suspend_suppliers(struct device *dev)
 {
     struct device_link *link;
     int idx = device_links_read_lock();
 
     list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
                 device_links_read_lock_held())
         pm_request_idle(link->supplier);
 
     device_links_read_unlock(idx);
 }
 
 /**
  * __rpm_callback - Run a given runtime PM callback for a given device.
  * @cb: Runtime PM callback to run.
  * @dev: Device to run the callback for.
  */
 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
     __releases(&dev->power.lock) __acquires(&dev->power.lock)
 {
     int retval = 0, idx;
     bool use_links = dev->power.links_count > 0;
 
     if (dev->power.irq_safe) {
         spin_unlock(&dev->power.lock);
     } else {
         spin_unlock_irq(&dev->power.lock);
 
         /*
          * Resume suppliers if necessary.
          *
          * The device's runtime PM status cannot change until this
          * routine returns, so it is safe to read the status outside of
          * the lock.
          */
         if (use_links && dev->power.runtime_status == RPM_RESUMING) {
             idx = device_links_read_lock();
 
             retval = rpm_get_suppliers(dev);
             if (retval) {
                 rpm_put_suppliers(dev);
                 goto fail;
             }
 
             device_links_read_unlock(idx);
         }
     }
 
     if (cb)
         retval = cb(dev);
 
     if (dev->power.irq_safe) {
         spin_lock(&dev->power.lock);
     } else {
         /*
          * If the device is suspending and the callback has returned
          * success, drop the usage counters of the suppliers that have
          * been reference counted on its resume.
          *
          * Do that if resume fails too.
          */
         if (use_links
             && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
             || (dev->power.runtime_status == RPM_RESUMING && retval))) {
             idx = device_links_read_lock();
 
             __rpm_put_suppliers(dev, false);
 
 fail:
             device_links_read_unlock(idx);
         }
 
         spin_lock_irq(&dev->power.lock);
     }
 
     return retval;
 }
 
 /**
  * rpm_idle - Notify device bus type if the device can be suspended.
  * @dev: Device to notify the bus type about.
  * @rpmflags: Flag bits.
  *
  * Check if the device's runtime PM status allows it to be suspended.  If
  * another idle notification has been started earlier, return immediately.  If
  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
  * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
  * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
  *
  * This function must be called under dev->power.lock with interrupts disabled.
  */
 static int rpm_idle(struct device *dev, int rpmflags)
 {
     int (*callback)(struct device *);
     int retval;
 
     trace_rpm_idle_rcuidle(dev, rpmflags);
     retval = rpm_check_suspend_allowed(dev);
     if (retval < 0)
         ;   /* Conditions are wrong. */
 
     /* Idle notifications are allowed only in the RPM_ACTIVE state. */
     else if (dev->power.runtime_status != RPM_ACTIVE)
         retval = -EAGAIN;
 
     /*
      * Any pending request other than an idle notification takes
      * precedence over us, except that the timer may be running.
      */
     else if (dev->power.request_pending &&
         dev->power.request > RPM_REQ_IDLE)
         retval = -EAGAIN;
 
     /* Act as though RPM_NOWAIT is always set. */
     else if (dev->power.idle_notification)
         retval = -EINPROGRESS;
     if (retval)
         goto out;
 
     /* Pending requests need to be canceled. */
     dev->power.request = RPM_REQ_NONE;
 
     callback = RPM_GET_CALLBACK(dev, runtime_idle);
 
     /* If no callback assume success. */
     if (!callback || dev->power.no_callbacks)
         goto out;
 
     /* Carry out an asynchronous or a synchronous idle notification. */
     if (rpmflags & RPM_ASYNC) {
         dev->power.request = RPM_REQ_IDLE;
         if (!dev->power.request_pending) {
             dev->power.request_pending = true;
             queue_work(pm_wq, &dev->power.work);
         }
         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
         return 0;
     }
 
     dev->power.idle_notification = true;
 
     retval = __rpm_callback(callback, dev);
 
     dev->power.idle_notification = false;
     wake_up_all(&dev->power.wait_queue);
 
  out:
     trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
     return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
 }
 
 /**
  * rpm_callback - Run a given runtime PM callback for a given device.
  * @cb: Runtime PM callback to run.
  * @dev: Device to run the callback for.
  */
 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 {
     int retval;
 
     if (dev->power.memalloc_noio) {
         unsigned int noio_flag;
 
         /*
          * Deadlock might be caused if memory allocation with
          * GFP_KERNEL happens inside runtime_suspend and
          * runtime_resume callbacks of one block device's
          * ancestor or the block device itself. Network
          * device might be thought as part of iSCSI block
          * device, so network device and its ancestor should
          * be marked as memalloc_noio too.
          */
         noio_flag = memalloc_noio_save();
         retval = __rpm_callback(cb, dev);
         memalloc_noio_restore(noio_flag);
     } else {
         retval = __rpm_callback(cb, dev);
     }
 
     dev->power.runtime_error = retval;
     return retval != -EACCES ? retval : -EIO;
 }
 
 /**
  * rpm_suspend - Carry out runtime suspend of given device.
  * @dev: Device to suspend.
  * @rpmflags: Flag bits.
  *
  * Check if the device's runtime PM status allows it to be suspended.
  * Cancel a pending idle notification, autosuspend or suspend. If
  * another suspend has been started earlier, either return immediately
  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
  * otherwise run the ->runtime_suspend() callback directly. When
  * ->runtime_suspend succeeded, if a deferred resume was requested while
  * the callback was running then carry it out, otherwise send an idle
  * notification for its parent (if the suspend succeeded and both
  * ignore_children of parent->power and irq_safe of dev->power are not set).
  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
  * flag is set and the next autosuspend-delay expiration time is in the
  * future, schedule another autosuspend attempt.
  *
  * This function must be called under dev->power.lock with interrupts disabled.
  */
 static int rpm_suspend(struct device *dev, int rpmflags)
     __releases(&dev->power.lock) __acquires(&dev->power.lock)
 {
     int (*callback)(struct device *);
     struct device *parent = NULL;
     int retval;
 
     trace_rpm_suspend_rcuidle(dev, rpmflags);
 
  repeat:
     retval = rpm_check_suspend_allowed(dev);
     if (retval < 0)
         goto out;   /* Conditions are wrong. */
 
     /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
     if (dev->power.runtime_status == RPM_RESUMING && !(rpmflags & RPM_ASYNC))
         retval = -EAGAIN;
     if (retval)
         goto out;
 
     /* If the autosuspend_delay time hasn't expired yet, reschedule. */
     if ((rpmflags & RPM_AUTO)
         && dev->power.runtime_status != RPM_SUSPENDING) {
         u64 expires = pm_runtime_autosuspend_expiration(dev);
 
         if (expires != 0) {
             /* Pending requests need to be canceled. */
             dev->power.request = RPM_REQ_NONE;
 
             /*
              * Optimization: If the timer is already running and is
              * set to expire at or before the autosuspend delay,
              * avoid the overhead of resetting it.  Just let it
              * expire; pm_suspend_timer_fn() will take care of the
              * rest.
              */
             if (!(dev->power.timer_expires &&
                     dev->power.timer_expires <= expires)) {
                 /*
                  * We add a slack of 25% to gather wakeups
                  * without sacrificing the granularity.
                  */
                 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
                             (NSEC_PER_MSEC >> 2);
 
                 dev->power.timer_expires = expires;
                 hrtimer_start_range_ns(&dev->power.suspend_timer,
                         ns_to_ktime(expires),
                         slack,
                         HRTIMER_MODE_ABS);
             }
             dev->power.timer_autosuspends = 1;
             goto out;
         }
     }
 
     /* Other scheduled or pending requests need to be canceled. */
     pm_runtime_cancel_pending(dev);
 
     if (dev->power.runtime_status == RPM_SUSPENDING) {
         DEFINE_WAIT(wait);
 
         if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
             retval = -EINPROGRESS;
             goto out;
         }
 
         if (dev->power.irq_safe) {
             spin_unlock(&dev->power.lock);
 
             cpu_relax();
 
             spin_lock(&dev->power.lock);
             goto repeat;
         }
 
         /* Wait for the other suspend running in parallel with us. */
         for (;;) {
             prepare_to_wait(&dev->power.wait_queue, &wait,
                     TASK_UNINTERRUPTIBLE);
             if (dev->power.runtime_status != RPM_SUSPENDING)
                 break;
 
             spin_unlock_irq(&dev->power.lock);
 
             schedule();
 
             spin_lock_irq(&dev->power.lock);
         }
         finish_wait(&dev->power.wait_queue, &wait);
         goto repeat;
     }
 
     if (dev->power.no_callbacks)
         goto no_callback;   /* Assume success. */
 
     /* Carry out an asynchronous or a synchronous suspend. */
     if (rpmflags & RPM_ASYNC) {
         dev->power.request = (rpmflags & RPM_AUTO) ?
             RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
         if (!dev->power.request_pending) {
             dev->power.request_pending = true;
             queue_work(pm_wq, &dev->power.work);
         }
         goto out;
     }
 
     __update_runtime_status(dev, RPM_SUSPENDING);
 
     callback = RPM_GET_CALLBACK(dev, runtime_suspend);
 
     dev_pm_enable_wake_irq_check(dev, true);
     retval = rpm_callback(callback, dev);
     if (retval)
         goto fail;
 
     dev_pm_enable_wake_irq_complete(dev);
 
  no_callback:
     __update_runtime_status(dev, RPM_SUSPENDED);
     pm_runtime_deactivate_timer(dev);
 
     if (dev->parent) {
         parent = dev->parent;
         atomic_add_unless(&parent->power.child_count, -1, 0);
     }
     wake_up_all(&dev->power.wait_queue);
 
     if (dev->power.deferred_resume) {
         dev->power.deferred_resume = false;
         rpm_resume(dev, 0);
         retval = -EAGAIN;
         goto out;
     }
 
     if (dev->power.irq_safe)
         goto out;
 
     /* Maybe the parent is now able to suspend. */
     if (parent && !parent->power.ignore_children) {
         spin_unlock(&dev->power.lock);
 
         spin_lock(&parent->power.lock);
         rpm_idle(parent, RPM_ASYNC);
         spin_unlock(&parent->power.lock);
 
         spin_lock(&dev->power.lock);
     }
     /* Maybe the suppliers are now able to suspend. */
     if (dev->power.links_count > 0) {
         spin_unlock_irq(&dev->power.lock);
 
         rpm_suspend_suppliers(dev);
 
         spin_lock_irq(&dev->power.lock);
     }
 
  out:
     trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 
     return retval;
 
  fail:
     dev_pm_disable_wake_irq_check(dev, true);
     __update_runtime_status(dev, RPM_ACTIVE);
     dev->power.deferred_resume = false;
     wake_up_all(&dev->power.wait_queue);
 
     if (retval == -EAGAIN || retval == -EBUSY) {
         dev->power.runtime_error = 0;
 
         /*
          * If the callback routine failed an autosuspend, and
          * if the last_busy time has been updated so that there
          * is a new autosuspend expiration time, automatically
          * reschedule another autosuspend.
          */
         if ((rpmflags & RPM_AUTO) &&
             pm_runtime_autosuspend_expiration(dev) != 0)
             goto repeat;
     } else {
         pm_runtime_cancel_pending(dev);
     }
     goto out;
 }
 
 /**
  * rpm_resume - Carry out runtime resume of given device.
  * @dev: Device to resume.
  * @rpmflags: Flag bits.
  *
  * Check if the device's runtime PM status allows it to be resumed.  Cancel
  * any scheduled or pending requests.  If another resume has been started
  * earlier, either return immediately or wait for it to finish, depending on the
  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
  * parallel with this function, either tell the other process to resume after
  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
  * flag is set then queue a resume request; otherwise run the
  * ->runtime_resume() callback directly.  Queue an idle notification for the
  * device if the resume succeeded.
  *
  * This function must be called under dev->power.lock with interrupts disabled.
  */
 static int rpm_resume(struct device *dev, int rpmflags)
     __releases(&dev->power.lock) __acquires(&dev->power.lock)
 {
     int (*callback)(struct device *);
     struct device *parent = NULL;
     int retval = 0;
 
     trace_rpm_resume_rcuidle(dev, rpmflags);
 
  repeat:
     if (dev->power.runtime_error) {
         retval = -EINVAL;
     } else if (dev->power.disable_depth > 0) {
         if (dev->power.runtime_status == RPM_ACTIVE &&
             dev->power.last_status == RPM_ACTIVE)
             retval = 1;
         else
             retval = -EACCES;
     }
     if (retval)
         goto out;
 
     /*
      * Other scheduled or pending requests need to be canceled.  Small
      * optimization: If an autosuspend timer is running, leave it running
      * rather than cancelling it now only to restart it again in the near
      * future.
      */
     dev->power.request = RPM_REQ_NONE;
     if (!dev->power.timer_autosuspends)
         pm_runtime_deactivate_timer(dev);
 
     if (dev->power.runtime_status == RPM_ACTIVE) {
         retval = 1;
         goto out;
     }
 
     if (dev->power.runtime_status == RPM_RESUMING
         || dev->power.runtime_status == RPM_SUSPENDING) {
         DEFINE_WAIT(wait);
 
         if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
             if (dev->power.runtime_status == RPM_SUSPENDING)
                 dev->power.deferred_resume = true;
             else
                 retval = -EINPROGRESS;
             goto out;
         }
 
         if (dev->power.irq_safe) {
             spin_unlock(&dev->power.lock);
 
             cpu_relax();
 
             spin_lock(&dev->power.lock);
             goto repeat;
         }
 
         /* Wait for the operation carried out in parallel with us. */
         for (;;) {
             prepare_to_wait(&dev->power.wait_queue, &wait,
                     TASK_UNINTERRUPTIBLE);
             if (dev->power.runtime_status != RPM_RESUMING
                 && dev->power.runtime_status != RPM_SUSPENDING)
                 break;
 
             spin_unlock_irq(&dev->power.lock);
 
             schedule();
 
             spin_lock_irq(&dev->power.lock);
         }
         finish_wait(&dev->power.wait_queue, &wait);
         goto repeat;
     }
 
     /*
      * See if we can skip waking up the parent.  This is safe only if
      * power.no_callbacks is set, because otherwise we don't know whether
      * the resume will actually succeed.
      */
     if (dev->power.no_callbacks && !parent && dev->parent) {
         spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
         if (dev->parent->power.disable_depth > 0
             || dev->parent->power.ignore_children
             || dev->parent->power.runtime_status == RPM_ACTIVE) {
             atomic_inc(&dev->parent->power.child_count);
             spin_unlock(&dev->parent->power.lock);
             retval = 1;
             goto no_callback;   /* Assume success. */
         }
         spin_unlock(&dev->parent->power.lock);
     }
 
     /* Carry out an asynchronous or a synchronous resume. */
     if (rpmflags & RPM_ASYNC) {
         dev->power.request = RPM_REQ_RESUME;
         if (!dev->power.request_pending) {
             dev->power.request_pending = true;
             queue_work(pm_wq, &dev->power.work);
         }
         retval = 0;
         goto out;
     }
 
     if (!parent && dev->parent) {
         /*
          * Increment the parent's usage counter and resume it if
          * necessary.  Not needed if dev is irq-safe; then the
          * parent is permanently resumed.
          */
         parent = dev->parent;
         if (dev->power.irq_safe)
             goto skip_parent;
         spin_unlock(&dev->power.lock);
 
         pm_runtime_get_noresume(parent);
 
         spin_lock(&parent->power.lock);
         /*
          * Resume the parent if it has runtime PM enabled and not been
          * set to ignore its children.
          */
         if (!parent->power.disable_depth
             && !parent->power.ignore_children) {
             rpm_resume(parent, 0);
             if (parent->power.runtime_status != RPM_ACTIVE)
                 retval = -EBUSY;
         }
         spin_unlock(&parent->power.lock);
 
         spin_lock(&dev->power.lock);
         if (retval)
             goto out;
         goto repeat;
     }
  skip_parent:
 
     if (dev->power.no_callbacks)
         goto no_callback;   /* Assume success. */
 
     __update_runtime_status(dev, RPM_RESUMING);
 
     callback = RPM_GET_CALLBACK(dev, runtime_resume);
 
     dev_pm_disable_wake_irq_check(dev, false);
     retval = rpm_callback(callback, dev);
     if (retval) {
         __update_runtime_status(dev, RPM_SUSPENDED);
         pm_runtime_cancel_pending(dev);
         dev_pm_enable_wake_irq_check(dev, false);
     } else {
  no_callback:
         __update_runtime_status(dev, RPM_ACTIVE);
         pm_runtime_mark_last_busy(dev);
         if (parent)
             atomic_inc(&parent->power.child_count);
     }
     wake_up_all(&dev->power.wait_queue);
 
     if (retval >= 0)
         rpm_idle(dev, RPM_ASYNC);
 
  out:
     if (parent && !dev->power.irq_safe) {
         spin_unlock_irq(&dev->power.lock);
 
         pm_runtime_put(parent);
 
         spin_lock_irq(&dev->power.lock);
     }
 
     trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 
     return retval;
 }
 
 /**
  * pm_runtime_work - Universal runtime PM work function.
  * @work: Work structure used for scheduling the execution of this function.
  *
  * Use @work to get the device object the work is to be done for, determine what
  * is to be done and execute the appropriate runtime PM function.
  */
 static void pm_runtime_work(struct work_struct *work)
 {
     struct device *dev = container_of(work, struct device, power.work);
     enum rpm_request req;
 
     spin_lock_irq(&dev->power.lock);
 
     if (!dev->power.request_pending)
         goto out;
 
     req = dev->power.request;
     dev->power.request = RPM_REQ_NONE;
     dev->power.request_pending = false;
 
     switch (req) {
     case RPM_REQ_NONE:
         break;
     case RPM_REQ_IDLE:
         rpm_idle(dev, RPM_NOWAIT);
         break;
     case RPM_REQ_SUSPEND:
         rpm_suspend(dev, RPM_NOWAIT);
         break;
     case RPM_REQ_AUTOSUSPEND:
         rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
         break;
     case RPM_REQ_RESUME:
         rpm_resume(dev, RPM_NOWAIT);
         break;
     }
 
  out:
     spin_unlock_irq(&dev->power.lock);
 }
 
 /**
  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
  * @timer: hrtimer used by pm_schedule_suspend().
  *
  * Check if the time is right and queue a suspend request.
  */
 static enum hrtimer_restart  pm_suspend_timer_fn(struct hrtimer *timer)
 {
     struct device *dev = container_of(timer, struct device, power.suspend_timer);
     unsigned long flags;
     u64 expires;
 
     spin_lock_irqsave(&dev->power.lock, flags);
 
     expires = dev->power.timer_expires;
     /*
      * If 'expires' is after the current time, we've been called
      * too early.
      */
     if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
         dev->power.timer_expires = 0;
         rpm_suspend(dev, dev->power.timer_autosuspends ?
             (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
     }
 
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     return HRTIMER_NORESTART;
 }
 
 /**
  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
  * @dev: Device to suspend.
  * @delay: Time to wait before submitting a suspend request, in milliseconds.
  */
 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 {
     unsigned long flags;
     u64 expires;
     int retval;
 
     spin_lock_irqsave(&dev->power.lock, flags);
 
     if (!delay) {
         retval = rpm_suspend(dev, RPM_ASYNC);
         goto out;
     }
 
     retval = rpm_check_suspend_allowed(dev);
     if (retval)
         goto out;
 
     /* Other scheduled or pending requests need to be canceled. */
     pm_runtime_cancel_pending(dev);
 
     expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
     dev->power.timer_expires = expires;
     dev->power.timer_autosuspends = 0;
     hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
 
  out:
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     return retval;
 }
 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 
 static int rpm_drop_usage_count(struct device *dev)
 {
     int ret;
 
     ret = atomic_sub_return(1, &dev->power.usage_count);
     if (ret >= 0)
         return ret;
 
     /*
      * Because rpm_resume() does not check the usage counter, it will resume
      * the device even if the usage counter is 0 or negative, so it is
      * sufficient to increment the usage counter here to reverse the change
      * made above.
      */
     atomic_inc(&dev->power.usage_count);
     dev_warn(dev, "Runtime PM usage count underflow!\n");
     return -EINVAL;
 }
 
 /**
  * __pm_runtime_idle - Entry point for runtime idle operations.
  * @dev: Device to send idle notification for.
  * @rpmflags: Flag bits.
  *
  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
  * return immediately if it is larger than zero (if it becomes negative, log a
  * warning, increment it, and return an error).  Then carry out an idle
  * notification, either synchronous or asynchronous.
  *
  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
  * or if pm_runtime_irq_safe() has been called.
  */
 int __pm_runtime_idle(struct device *dev, int rpmflags)
 {
     unsigned long flags;
     int retval;
 
     if (rpmflags & RPM_GET_PUT) {
         retval = rpm_drop_usage_count(dev);
         if (retval < 0) {
             return retval;
         } else if (retval > 0) {
             trace_rpm_usage_rcuidle(dev, rpmflags);
             return 0;
         }
     }
 
     might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 
     spin_lock_irqsave(&dev->power.lock, flags);
     retval = rpm_idle(dev, rpmflags);
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     return retval;
 }
 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
 
 /**
  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
  * @dev: Device to suspend.
  * @rpmflags: Flag bits.
  *
  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
  * return immediately if it is larger than zero (if it becomes negative, log a
  * warning, increment it, and return an error).  Then carry out a suspend,
  * either synchronous or asynchronous.
  *
  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
  * or if pm_runtime_irq_safe() has been called.
  */
 int __pm_runtime_suspend(struct device *dev, int rpmflags)
 {
     unsigned long flags;
     int retval;
 
     if (rpmflags & RPM_GET_PUT) {
         retval = rpm_drop_usage_count(dev);
         if (retval < 0) {
             return retval;
         } else if (retval > 0) {
             trace_rpm_usage_rcuidle(dev, rpmflags);
             return 0;
         }
     }
 
     might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 
     spin_lock_irqsave(&dev->power.lock, flags);
     retval = rpm_suspend(dev, rpmflags);
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     return retval;
 }
 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
 
 /**
  * __pm_runtime_resume - Entry point for runtime resume operations.
  * @dev: Device to resume.
  * @rpmflags: Flag bits.
  *
  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
  * carry out a resume, either synchronous or asynchronous.
  *
  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
  * or if pm_runtime_irq_safe() has been called.
  */
 int __pm_runtime_resume(struct device *dev, int rpmflags)
 {
     unsigned long flags;
     int retval;
 
     might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
             dev->power.runtime_status != RPM_ACTIVE);
 
     if (rpmflags & RPM_GET_PUT)
         atomic_inc(&dev->power.usage_count);
 
     spin_lock_irqsave(&dev->power.lock, flags);
     retval = rpm_resume(dev, rpmflags);
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     return retval;
 }
 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 
 /**
  * pm_runtime_get_if_active - Conditionally bump up device usage counter.
  * @dev: Device to handle.
  * @ign_usage_count: Whether or not to look at the current usage counter value.
  *
  * Return -EINVAL if runtime PM is disabled for @dev.
  *
  * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
  * @ign_usage_count is %true or the runtime PM usage counter of @dev is not
  * zero, increment the usage counter of @dev and return 1. Otherwise, return 0
  * without changing the usage counter.
  *
  * If @ign_usage_count is %true, this function can be used to prevent suspending
  * the device when its runtime PM status is %RPM_ACTIVE.
  *
  * If @ign_usage_count is %false, this function can be used to prevent
  * suspending the device when both its runtime PM status is %RPM_ACTIVE and its
  * runtime PM usage counter is not zero.
  *
  * The caller is responsible for decrementing the runtime PM usage counter of
  * @dev after this function has returned a positive value for it.
  */
 int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
 {
     unsigned long flags;
     int retval;
 
     spin_lock_irqsave(&dev->power.lock, flags);
     if (dev->power.disable_depth > 0) {
         retval = -EINVAL;
     } else if (dev->power.runtime_status != RPM_ACTIVE) {
         retval = 0;
     } else if (ign_usage_count) {
         retval = 1;
         atomic_inc(&dev->power.usage_count);
     } else {
         retval = atomic_inc_not_zero(&dev->power.usage_count);
     }
     trace_rpm_usage_rcuidle(dev, 0);
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     return retval;
 }
 EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
 
 /**
  * __pm_runtime_set_status - Set runtime PM status of a device.
  * @dev: Device to handle.
  * @status: New runtime PM status of the device.
  *
  * If runtime PM of the device is disabled or its power.runtime_error field is
  * different from zero, the status may be changed either to RPM_ACTIVE, or to
  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
  * However, if the device has a parent and the parent is not active, and the
  * parent's power.ignore_children flag is unset, the device's status cannot be
  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
  *
  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
  * and the device parent's counter of unsuspended children is modified to
  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
  * notification request for the parent is submitted.
  *
  * If @dev has any suppliers (as reflected by device links to them), and @status
  * is RPM_ACTIVE, they will be activated upfront and if the activation of one
  * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
  * of the @status value) and the suppliers will be deacticated on exit.  The
  * error returned by the failing supplier activation will be returned in that
  * case.
  */
 int __pm_runtime_set_status(struct device *dev, unsigned int status)
 {
     struct device *parent = dev->parent;
     bool notify_parent = false;
     unsigned long flags;
     int error = 0;
 
     if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
         return -EINVAL;
 
     spin_lock_irqsave(&dev->power.lock, flags);
 
     /*
      * Prevent PM-runtime from being enabled for the device or return an
      * error if it is enabled already and working.
      */
     if (dev->power.runtime_error || dev->power.disable_depth)
         dev->power.disable_depth++;
     else
         error = -EAGAIN;
 
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     if (error)
         return error;
 
     /*
      * If the new status is RPM_ACTIVE, the suppliers can be activated
      * upfront regardless of the current status, because next time
      * rpm_put_suppliers() runs, the rpm_active refcounts of the links
      * involved will be dropped down to one anyway.
      */
     if (status == RPM_ACTIVE) {
         int idx = device_links_read_lock();
 
         error = rpm_get_suppliers(dev);
         if (error)
             status = RPM_SUSPENDED;
 
         device_links_read_unlock(idx);
     }
 
     spin_lock_irqsave(&dev->power.lock, flags);
 
     if (dev->power.runtime_status == status || !parent)
         goto out_set;
 
     if (status == RPM_SUSPENDED) {
         atomic_add_unless(&parent->power.child_count, -1, 0);
         notify_parent = !parent->power.ignore_children;
     } else {
         spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
 
         /*
          * It is invalid to put an active child under a parent that is
          * not active, has runtime PM enabled and the
          * 'power.ignore_children' flag unset.
          */
         if (!parent->power.disable_depth
             && !parent->power.ignore_children
             && parent->power.runtime_status != RPM_ACTIVE) {
             dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
                 dev_name(dev),
                 dev_name(parent));
             error = -EBUSY;
         } else if (dev->power.runtime_status == RPM_SUSPENDED) {
             atomic_inc(&parent->power.child_count);
         }
 
         spin_unlock(&parent->power.lock);
 
         if (error) {
             status = RPM_SUSPENDED;
             goto out;
         }
     }
 
  out_set:
     __update_runtime_status(dev, status);
     if (!error)
         dev->power.runtime_error = 0;
 
  out:
     spin_unlock_irqrestore(&dev->power.lock, flags);
 
     if (notify_parent)
         pm_request_idle(parent);
 
     if (status == RPM_SUSPENDED) {
         int idx = device_links_read_lock();
 
         rpm_put_suppliers(dev);
 
         device_links_read_unlock(idx);
     }
 
     pm_runtime_enable(dev);
 
     return error;
 }
 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
 
 /**
  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
  * @dev: Device to handle.
  *
  * Flush all pending requests for the device from pm_wq and wait for all
  * runtime PM operations involving the device in progress to complete.
  *
  * Should be called under dev->power.lock with interrupts disabled.
  */
 static void __pm_runtime_barrier(struct device *dev)
 {
     pm_runtime_deactivate_timer(dev);
 
     if (dev->power.request_pending) {
         dev->power.request = RPM_REQ_NONE;
         spin_unlock_irq(&dev->power.lock);
 
         cancel_work_sync(&dev->power.work);
 
         spin_lock_irq(&dev->power.lock);
         dev->power.request_pending = false;
     }
 
     if (dev->power.runtime_status == RPM_SUSPENDING
         || dev->power.runtime_status == RPM_RESUMING
         || dev->power.idle_notification) {
         DEFINE_WAIT(wait);
 
         /* Suspend, wake-up or idle notification in progress. */
         for (;;) {
             prepare_to_wait(&dev->power.wait_queue, &wait,
                     TASK_UNINTERRUPTIBLE);
             if (dev->power.runtime_status != RPM_SUSPENDING
                 && dev->power.runtime_status != RPM_RESUMING
                 && !dev->power.idle_notification)
                 break;
             spin_unlock_irq(&dev->power.lock);
 
             schedule();
 
             spin_lock_irq(&dev->power.lock);
         }
         finish_wait(&dev->power.wait_queue, &wait);
     }
 }
 
 /**
  * pm_runtime_barrier - Flush pending requests and wait for completions.
  * @dev: Device to handle.
  *
  * Prevent the device from being suspended by incrementing its usage counter and
  * if there's a pending resume request for the device, wake the device up.
  * Next, make sure that all pending requests for the device have been flushed
  * from pm_wq and wait for all runtime PM operations involving the device in
  * progress to complete.
  *
  * Return value:
  * 1, if there was a resume request pending and the device had to be woken up,
  * 0, otherwise
  */
 int pm_runtime_barrier(struct device *dev)
 {
     int retval = 0;
 
     pm_runtime_get_noresume(dev);
     spin_lock_irq(&dev->power.lock);
 
     if (dev->power.request_pending
         && dev->power.request == RPM_REQ_RESUME) {
         rpm_resume(dev, 0);
         retval = 1;
     }
 
     __pm_runtime_barrier(dev);
 
     spin_unlock_irq(&dev->power.lock);
     pm_runtime_put_noidle(dev);
 
     return retval;
 }
 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
 
 /**
  * __pm_runtime_disable - Disable runtime PM of a device.
  * @dev: Device to handle.
  * @check_resume: If set, check if there's a resume request for the device.
  *
  * Increment power.disable_depth for the device and if it was zero previously,
  * cancel all pending runtime PM requests for the device and wait for all
  * operations in progress to complete.  The device can be either active or
  * suspended after its runtime PM has been disabled.
  *
  * If @check_resume is set and there's a resume request pending when
  * __pm_runtime_disable() is called and power.disable_depth is zero, the
  * function will wake up the device before disabling its runtime PM.
  */
 void __pm_runtime_disable(struct device *dev, bool check_resume)
 {
     spin_lock_irq(&dev->power.lock);
 
     if (dev->power.disable_depth > 0) {
         dev->power.disable_depth++;
         goto out;
     }
 
     /*
      * Wake up the device if there's a resume request pending, because that
      * means there probably is some I/O to process and disabling runtime PM
      * shouldn't prevent the device from processing the I/O.
      */
     if (check_resume && dev->power.request_pending
         && dev->power.request == RPM_REQ_RESUME) {
         /*
          * Prevent suspends and idle notifications from being carried
          * out after we have woken up the device.
          */
         pm_runtime_get_noresume(dev);
 
         rpm_resume(dev, 0);
 
         pm_runtime_put_noidle(dev);
     }
 
     /* Update time accounting before disabling PM-runtime. */
     update_pm_runtime_accounting(dev);
 
     if (!dev->power.disable_depth++) {
         __pm_runtime_barrier(dev);
         dev->power.last_status = dev->power.runtime_status;
     }
 
  out:
     spin_unlock_irq(&dev->power.lock);
 }
 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
 
 /**
  * pm_runtime_enable - Enable runtime PM of a device.
  * @dev: Device to handle.
  */
 void pm_runtime_enable(struct device *dev)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&dev->power.lock, flags);
 
     if (!dev->power.disable_depth) {
         dev_warn(dev, "Unbalanced %s!\n", __func__);
         goto out;
     }
 
     if (--dev->power.disable_depth > 0)
         goto out;
 
     dev->power.last_status = RPM_INVALID;
     dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
 
     if (dev->power.runtime_status == RPM_SUSPENDED &&
         !dev->power.ignore_children &&
         atomic_read(&dev->power.child_count) > 0)
         dev_warn(dev, "Enabling runtime PM for inactive device with active children\n");
 
 out:
     spin_unlock_irqrestore(&dev->power.lock, flags);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_enable);
 
 static void pm_runtime_disable_action(void *data)
 {
     pm_runtime_dont_use_autosuspend(data);
     pm_runtime_disable(data);
 }
 
 /**
  * devm_pm_runtime_enable - devres-enabled version of pm_runtime_enable.
  *
  * NOTE: this will also handle calling pm_runtime_dont_use_autosuspend() for
  * you at driver exit time if needed.
  *
  * @dev: Device to handle.
  */
 int devm_pm_runtime_enable(struct device *dev)
 {
     pm_runtime_enable(dev);
 
     return devm_add_action_or_reset(dev, pm_runtime_disable_action, dev);
 }
 EXPORT_SYMBOL_GPL(devm_pm_runtime_enable);
 
 /**
  * pm_runtime_forbid - Block runtime PM of a device.
  * @dev: Device to handle.
  *
  * Increase the device's usage count and clear its power.runtime_auto flag,
  * so that it cannot be suspended at run time until pm_runtime_allow() is called
  * for it.
  */
 void pm_runtime_forbid(struct device *dev)
 {
     spin_lock_irq(&dev->power.lock);
     if (!dev->power.runtime_auto)
         goto out;
 
     dev->power.runtime_auto = false;
     atomic_inc(&dev->power.usage_count);
     rpm_resume(dev, 0);
 
  out:
     spin_unlock_irq(&dev->power.lock);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
 
 /**
  * pm_runtime_allow - Unblock runtime PM of a device.
  * @dev: Device to handle.
  *
  * Decrease the device's usage count and set its power.runtime_auto flag.
  */
 void pm_runtime_allow(struct device *dev)
 {
     int ret;
 
     spin_lock_irq(&dev->power.lock);
     if (dev->power.runtime_auto)
         goto out;
 
     dev->power.runtime_auto = true;
     ret = rpm_drop_usage_count(dev);
     if (ret == 0)
         rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
     else if (ret > 0)
         trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
 
  out:
     spin_unlock_irq(&dev->power.lock);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_allow);
 
 /**
  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
  * @dev: Device to handle.
  *
  * Set the power.no_callbacks flag, which tells the PM core that this
  * device is power-managed through its parent and has no runtime PM
  * callbacks of its own.  The runtime sysfs attributes will be removed.
  */
 void pm_runtime_no_callbacks(struct device *dev)
 {
     spin_lock_irq(&dev->power.lock);
     dev->power.no_callbacks = 1;
     spin_unlock_irq(&dev->power.lock);
     if (device_is_registered(dev))
         rpm_sysfs_remove(dev);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
 
 /**
  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
  * @dev: Device to handle
  *
  * Set the power.irq_safe flag, which tells the PM core that the
  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
  * always be invoked with the spinlock held and interrupts disabled.  It also
  * causes the parent's usage counter to be permanently incremented, preventing
  * the parent from runtime suspending -- otherwise an irq-safe child might have
  * to wait for a non-irq-safe parent.
  */
 void pm_runtime_irq_safe(struct device *dev)
 {
     if (dev->parent)
         pm_runtime_get_sync(dev->parent);
     spin_lock_irq(&dev->power.lock);
     dev->power.irq_safe = 1;
     spin_unlock_irq(&dev->power.lock);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
 
 /**
  * update_autosuspend - Handle a change to a device's autosuspend settings.
  * @dev: Device to handle.
  * @old_delay: The former autosuspend_delay value.
  * @old_use: The former use_autosuspend value.
  *
  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
  *
  * This function must be called under dev->power.lock with interrupts disabled.
  */
 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
 {
     int delay = dev->power.autosuspend_delay;
 
     /* Should runtime suspend be prevented now? */
     if (dev->power.use_autosuspend && delay < 0) {
 
         /* If it used to be allowed then prevent it. */
         if (!old_use || old_delay >= 0) {
             atomic_inc(&dev->power.usage_count);
             rpm_resume(dev, 0);
         } else {
             trace_rpm_usage_rcuidle(dev, 0);
         }
     }
 
     /* Runtime suspend should be allowed now. */
     else {
 
         /* If it used to be prevented then allow it. */
         if (old_use && old_delay < 0)
             atomic_dec(&dev->power.usage_count);
 
         /* Maybe we can autosuspend now. */
         rpm_idle(dev, RPM_AUTO);
     }
 }
 
 /**
  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
  * @dev: Device to handle.
  * @delay: Value of the new delay in milliseconds.
  *
  * Set the device's power.autosuspend_delay value.  If it changes to negative
  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
  * changes the other way, allow runtime suspends.
  */
 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
 {
     int old_delay, old_use;
 
     spin_lock_irq(&dev->power.lock);
     old_delay = dev->power.autosuspend_delay;
     old_use = dev->power.use_autosuspend;
     dev->power.autosuspend_delay = delay;
     update_autosuspend(dev, old_delay, old_use);
     spin_unlock_irq(&dev->power.lock);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
 
 /**
  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
  * @dev: Device to handle.
  * @use: New value for use_autosuspend.
  *
  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
  * suspends as needed.
  */
 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
 {
     int old_delay, old_use;
 
     spin_lock_irq(&dev->power.lock);
     old_delay = dev->power.autosuspend_delay;
     old_use = dev->power.use_autosuspend;
     dev->power.use_autosuspend = use;
     update_autosuspend(dev, old_delay, old_use);
     spin_unlock_irq(&dev->power.lock);
 }
 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
 
 /**
  * pm_runtime_init - Initialize runtime PM fields in given device object.
  * @dev: Device object to initialize.
  */
 void pm_runtime_init(struct device *dev)
 {
     dev->power.runtime_status = RPM_SUSPENDED;
     dev->power.last_status = RPM_INVALID;
     dev->power.idle_notification = false;
 
     dev->power.disable_depth = 1;
     atomic_set(&dev->power.usage_count, 0);
 
     dev->power.runtime_error = 0;
 
     atomic_set(&dev->power.child_count, 0);
     pm_suspend_ignore_children(dev, false);
     dev->power.runtime_auto = true;
 
     dev->power.request_pending = false;
     dev->power.request = RPM_REQ_NONE;
     dev->power.deferred_resume = false;
     dev->power.needs_force_resume = 0;
     INIT_WORK(&dev->power.work, pm_runtime_work);
 
     dev->power.timer_expires = 0;
     hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
     dev->power.suspend_timer.function = pm_suspend_timer_fn;
 
     init_waitqueue_head(&dev->power.wait_queue);
 }
 
 /**
  * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
  * @dev: Device object to re-initialize.
  */
 void pm_runtime_reinit(struct device *dev)
 {
     if (!pm_runtime_enabled(dev)) {
         if (dev->power.runtime_status == RPM_ACTIVE)
             pm_runtime_set_suspended(dev);
         if (dev->power.irq_safe) {
             spin_lock_irq(&dev->power.lock);
             dev->power.irq_safe = 0;
             spin_unlock_irq(&dev->power.lock);
             if (dev->parent)
                 pm_runtime_put(dev->parent);
         }
     }
 }
 
 /**
  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
  * @dev: Device object being removed from device hierarchy.
  */
 void pm_runtime_remove(struct device *dev)
 {
     __pm_runtime_disable(dev, false);
     pm_runtime_reinit(dev);
 }
 
 /**
  * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
  * @dev: Consumer device.
  */
 void pm_runtime_get_suppliers(struct device *dev)
 {
     struct device_link *link;
     int idx;
 
     idx = device_links_read_lock();
 
     list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
                 device_links_read_lock_held())
         if (link->flags & DL_FLAG_PM_RUNTIME) {
             link->supplier_preactivated = true;
             pm_runtime_get_sync(link->supplier);
         }
 
     device_links_read_unlock(idx);
 }
 
 /**
  * pm_runtime_put_suppliers - Drop references to supplier devices.
  * @dev: Consumer device.
  */
 void pm_runtime_put_suppliers(struct device *dev)
 {
     struct device_link *link;
     int idx;
 
     idx = device_links_read_lock();
 
     list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
                 device_links_read_lock_held())
         if (link->supplier_preactivated) {
             link->supplier_preactivated = false;
             pm_runtime_put(link->supplier);
         }
 
     device_links_read_unlock(idx);
 }
 
 void pm_runtime_new_link(struct device *dev)
 {
     spin_lock_irq(&dev->power.lock);
     dev->power.links_count++;
     spin_unlock_irq(&dev->power.lock);
 }
 
 static void pm_runtime_drop_link_count(struct device *dev)
 {
     spin_lock_irq(&dev->power.lock);
     WARN_ON(dev->power.links_count == 0);
     dev->power.links_count--;
     spin_unlock_irq(&dev->power.lock);
 }
 
 /**
  * pm_runtime_drop_link - Prepare for device link removal.
  * @link: Device link going away.
  *
  * Drop the link count of the consumer end of @link and decrement the supplier
  * device's runtime PM usage counter as many times as needed to drop all of the
  * PM runtime reference to it from the consumer.
  */
 void pm_runtime_drop_link(struct device_link *link)
 {
     if (!(link->flags & DL_FLAG_PM_RUNTIME))
         return;
 
     pm_runtime_drop_link_count(link->consumer);
     pm_runtime_release_supplier(link);
     pm_request_idle(link->supplier);
 }
 
 static bool pm_runtime_need_not_resume(struct device *dev)
 {
     return atomic_read(&dev->power.usage_count) <= 1 &&
         (atomic_read(&dev->power.child_count) == 0 ||
          dev->power.ignore_children);
 }
 
 /**
  * pm_runtime_force_suspend - Force a device into suspend state if needed.
  * @dev: Device to suspend.
  *
  * Disable runtime PM so we safely can check the device's runtime PM status and
  * if it is active, invoke its ->runtime_suspend callback to suspend it and
  * change its runtime PM status field to RPM_SUSPENDED.  Also, if the device's
  * usage and children counters don't indicate that the device was in use before
  * the system-wide transition under way, decrement its parent's children counter
  * (if there is a parent).  Keep runtime PM disabled to preserve the state
  * unless we encounter errors.
  *
  * Typically this function may be invoked from a system suspend callback to make
  * sure the device is put into low power state and it should only be used during
  * system-wide PM transitions to sleep states.  It assumes that the analogous
  * pm_runtime_force_resume() will be used to resume the device.
  */
 int pm_runtime_force_suspend(struct device *dev)
 {
     int (*callback)(struct device *);
     int ret;
 
     pm_runtime_disable(dev);
     if (pm_runtime_status_suspended(dev))
         return 0;
 
     callback = RPM_GET_CALLBACK(dev, runtime_suspend);
 
     dev_pm_enable_wake_irq_check(dev, true);
     ret = callback ? callback(dev) : 0;
     if (ret)
         goto err;
 
     dev_pm_enable_wake_irq_complete(dev);
 
     /*
      * If the device can stay in suspend after the system-wide transition
      * to the working state that will follow, drop the children counter of
      * its parent, but set its status to RPM_SUSPENDED anyway in case this
      * function will be called again for it in the meantime.
      */
     if (pm_runtime_need_not_resume(dev)) {
         pm_runtime_set_suspended(dev);
     } else {
         __update_runtime_status(dev, RPM_SUSPENDED);
         dev->power.needs_force_resume = 1;
     }
 
     return 0;
 
 err:
     dev_pm_disable_wake_irq_check(dev, true);
     pm_runtime_enable(dev);
     return ret;
 }
 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
 
 /**
  * pm_runtime_force_resume - Force a device into resume state if needed.
  * @dev: Device to resume.
  *
  * Prior invoking this function we expect the user to have brought the device
  * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
  * those actions and bring the device into full power, if it is expected to be
  * used on system resume.  In the other case, we defer the resume to be managed
  * via runtime PM.
  *
  * Typically this function may be invoked from a system resume callback.
  */
 int pm_runtime_force_resume(struct device *dev)
 {
     int (*callback)(struct device *);
     int ret = 0;
 
     if (!pm_runtime_status_suspended(dev) || !dev->power.needs_force_resume)
         goto out;
 
     /*
      * The value of the parent's children counter is correct already, so
      * just update the status of the device.
      */
     __update_runtime_status(dev, RPM_ACTIVE);
 
     callback = RPM_GET_CALLBACK(dev, runtime_resume);
 
     dev_pm_disable_wake_irq_check(dev, false);
     ret = callback ? callback(dev) : 0;
     if (ret) {
         pm_runtime_set_suspended(dev);
         dev_pm_enable_wake_irq_check(dev, false);
         goto out;
     }
 
     pm_runtime_mark_last_busy(dev);
 out:
     dev->power.needs_force_resume = 0;
     pm_runtime_enable(dev);
     return ret;
 }
 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);

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