PM: sleep: core: Drop racy and redundant checks from device_prepare() (b5252a6c) · Commits · 戴 / test

Alan Stern points out that the WARN_ON() check in device_prepare() is racy (because the PM-runtime API can be disabled briefly for any device at any time and system suspend can start at any time too) and the pm_runtime_suspended() check in the computation of the direct_complete flag value is redundant (because it will be repeated later anyway). Drop both these checks accordingly. Reported-by:

Alan Stern <stern@rowland.harvard.edu> Signed-off-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/main.c

+1 −6

Original line number	Diff line number	Diff line
		@@ -1922,10 +1922,6 @@ static int device_prepare(struct device *dev, pm_message_t state)
		if (dev->power.syscore)
		return 0;

		WARN_ON(!pm_runtime_enabled(dev) &&
		dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND \|
		DPM_FLAG_LEAVE_SUSPENDED));

		/*
		* If a device's parent goes into runtime suspend at the wrong time,
		* it won't be possible to resume the device. To prevent this we
		@@ -1973,8 +1969,7 @@ unlock:
		*/
		spin_lock_irq(&dev->power.lock);
		dev->power.direct_complete = state.event == PM_EVENT_SUSPEND &&
		((pm_runtime_suspended(dev) && ret > 0) \|\|
		dev->power.no_pm_callbacks) &&
		(ret > 0 \|\| dev->power.no_pm_callbacks) &&
		!dev_pm_test_driver_flags(dev, DPM_FLAG_NEVER_SKIP);
		spin_unlock_irq(&dev->power.lock);
		return 0;

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