On Wednesday 02 December 2009, Alan Stern wrote:
> This patch (as1309) fixes a lockdep warning in
> __pm_runtime_set_status(). This is the one place where the runtime PM
> framework acquires a nested power.lock, and the nesting is never more
> than one deep.
>
> Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
I have a very simila patch queued up already. The only difference is that it
uses SINGLE_DEPTH_NESTING instead of the new symbol. My version is appended
below.
>
> ---
>
> If anybody is using the runtime PM framework in 2.6.32 then this
> should be pushed before the final release.
I'll push it to Linus, then, if there still is time. Would you mind if I used
my version?
Thanks,
Rafael
> Index: usb-2.6/drivers/base/power/runtime.c
> ===================================================================
> --- usb-2.6.orig/drivers/base/power/runtime.c
> +++ usb-2.6/drivers/base/power/runtime.c
> @@ -10,6 +10,8 @@
> #include <linux/pm_runtime.h>
> #include <linux/jiffies.h>
>
> +#define RPM_LOCK_PARENT 1
> +
> static int __pm_runtime_resume(struct device *dev, bool from_wq);
> static int __pm_request_idle(struct device *dev);
> static int __pm_request_resume(struct device *dev);
> @@ -793,7 +795,7 @@ int __pm_runtime_set_status(struct devic
> }
>
> if (parent) {
> - spin_lock(&parent->power.lock);
> + spin_lock_nested(&parent->power.lock, RPM_LOCK_PARENT);
>
> /*
> * It is invalid to put an active child under a parent that is
---
From: Rafael J. Wysocki <rjw@xxxxxxx>
Subject: PM / Runtime: Fix lockdep warning in __pm_runtime_set_status()
Lockdep complains about taking the parent lock in
__pm_runtime_set_status(), so mark it as nested.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
drivers/base/power/runtime.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/drivers/base/power/runtime.c
===================================================================
--- linux-2.6.orig/drivers/base/power/runtime.c
+++ linux-2.6/drivers/base/power/runtime.c
@@ -777,7 +777,7 @@ int __pm_runtime_set_status(struct devic
}
if (parent) {
- spin_lock(&parent->power.lock);
+ spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
/*
* It is invalid to put an active child under a parent that is
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