The below patch makes sure that dev->parent supports runtime PM before accessing its PM fields. Though the code does this check at a later point in time, doing it earlier can optimize the code flow.
Regards,
Nithish Mahalingam
>From 2e7fe2ea2737b8f70da20c8ec77235f8548d1331 Mon Sep 17 00:00:00 2001
From: Nithish Mahalingam <nithish.mahalingam@xxxxxxxxx>
Date: Thu, 3 Dec 2009 13:27:02 +0530
Subject: [PATCH] Adding explicit check to make sure dev->parent supports runtime PM before accessing its PM fields.
This patch adds explicit checks to make sure dev->parent supports runtime PM
before accessing any of its runtime PM fields.
modified: drivers/base/power/runtime.c
Signed-off-by: Nithish Mahalingam <nithish.mahalingam@xxxxxxxxx>
---
drivers/base/power/runtime.c | 18 +++++++++---------
1 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 846d89e..87ac2d6 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -209,7 +209,7 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
} else {
dev->power.runtime_status = RPM_SUSPENDED;
- if (dev->parent) {
+ if (dev->parent && !dev->parent->power.disable_depth) {
parent = dev->parent;
atomic_add_unless(&parent->power.child_count, -1, 0);
}
@@ -322,7 +322,7 @@ int __pm_runtime_resume(struct device *dev, bool from_wq)
goto repeat;
}
- if (!parent && dev->parent) {
+ if (dev->parent && !dev->parent->power.disable_depth) {
/*
* Increment the parent's resume counter and resume it if
* necessary.
@@ -334,11 +334,10 @@ int __pm_runtime_resume(struct device *dev, bool from_wq)
spin_lock(&parent->power.lock);
/*
- * We can resume if the parent's run-time PM is disabled or it
- * is set to ignore children.
+ * We can resume if the parent's run-time PM is set to
+ * ignore children.
*/
- if (!parent->power.disable_depth
- && !parent->power.ignore_children) {
+ if (!parent->power.ignore_children) {
__pm_runtime_resume(parent, false);
if (parent->power.runtime_status != RPM_ACTIVE)
retval = -EBUSY;
@@ -749,7 +748,9 @@ EXPORT_SYMBOL_GPL(__pm_runtime_put);
*/
int __pm_runtime_set_status(struct device *dev, unsigned int status)
{
- struct device *parent = dev->parent;
+ struct device *parent = dev->parent ?
+ (dev->parent->power.disable_depth ? NULL : dev->parent) :
+ NULL;
unsigned long flags;
bool notify_parent = false;
int error = 0;
@@ -784,8 +785,7 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status)
* not active, has run-time PM enabled and the
* 'power.ignore_children' flag unset.
*/
- if (!parent->power.disable_depth
- && !parent->power.ignore_children
+ if (!parent->power.ignore_children
&& parent->power.runtime_status != RPM_ACTIVE) {
error = -EBUSY;
} else {
--
1.6.5.2
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