With PREEMPT_RT spin_unlock() is identical to spin_unlock_irq() so there
is no reason to have a special case using the former. Furthermore,
spin_unlock() enables preemption meaning that a task in RESUMING or
SUSPENDING state may be preempted by a higher priority task running
pm_runtime_get_sync() leading to a livelock.
Use the non-irq_safe path for all waiting so that the waiting task will
block.
Note that this changes only the waiting behaviour of irq_safe, other
uses are left unchanged so that the parent device always remains active
in the same way as !RT.
Signed-off-by: John Keeping <john@xxxxxxxxxxxx>
---
drivers/base/power/runtime.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 96972d5f6ef3..5e0d349fab4e 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -347,8 +347,9 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
{
int retval = 0, idx;
bool use_links = dev->power.links_count > 0;
+ bool irq_safe = dev->power.irq_safe && !IS_ENABLED(CONFIG_PREEMPT_RT);
- if (dev->power.irq_safe) {
+ if (irq_safe) {
spin_unlock(&dev->power.lock);
} else {
spin_unlock_irq(&dev->power.lock);
@@ -376,7 +377,7 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
if (cb)
retval = cb(dev);
- if (dev->power.irq_safe) {
+ if (irq_safe) {
spin_lock(&dev->power.lock);
} else {
/*
@@ -596,7 +597,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
goto out;
}
- if (dev->power.irq_safe) {
+ if (dev->power.irq_safe && !IS_ENABLED(CONFIG_PREEMPT_RT)) {
spin_unlock(&dev->power.lock);
cpu_relax();
@@ -777,7 +778,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
goto out;
}
- if (dev->power.irq_safe) {
+ if (dev->power.irq_safe && !IS_ENABLED(CONFIG_PREEMPT_RT)) {
spin_unlock(&dev->power.lock);
cpu_relax();
--
2.33.0
