From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Alan Stern <stern@rowland.harvard.edu>
Subject: [PATCH] PM: sleep: core: Drop racy and redundant checks from device_prepare()
Date: Sun, 29 Mar 2020 16:11:18 +0200 [thread overview]
Message-ID: <1792393.Ra5xgIVOUU@kreacher> (raw)
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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 | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
Index: linux-pm/drivers/base/power/main.c
===================================================================
--- linux-pm.orig/drivers/base/power/main.c
+++ linux-pm/drivers/base/power/main.c
@@ -1922,10 +1922,6 @@ static int device_prepare(struct device
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;
reply other threads:[~2020-03-29 14:11 UTC|newest]
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