2007-10-18 17:05:52

by Geert Uytterhoeven

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Subject: wait_for_completion_interruptible() changes

Hi Andi, Ingo,

Recently the return value of wait_for_completion_interruptible() in case of
succesful completion has changed:
- in 2.6.23, it returns 0 on completion,
- in current linux-2.6.git, it returns -1 on completion.

I.e. this breaks all code that checks for a non-zero return value instead
of explicitly comparing with -ERESTARTSYS.

I suspect this is caused by the recent completion refactoring?

With kind regards,

Geert Uytterhoeven
Software Architect

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2007-10-18 17:41:56

by Andi Kleen

[permalink] [raw]
Subject: Re: wait_for_completion_interruptible() changes

> I suspect this is caused by the recent completion refactoring?

Yes. Here's a patch to fix it.

Fix return value of wait_for_completion_interruptible()

The recent w_f_c() changes broke the return value of
wait_for_completion_interruptible(). Previously it returned 0 on success,
now -1. Fix that.

Problem found by Geert Uytterhoeven

Signed-off-by: Andi Kleen <[email protected]>

Index: linux/kernel/sched.c
===================================================================
--- linux/kernel/sched.c
+++ linux/kernel/sched.c
@@ -3751,7 +3751,10 @@ EXPORT_SYMBOL(wait_for_completion_timeou

int __sched wait_for_completion_interruptible(struct completion *x)
{
- return wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
+ long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
+ if (t == -ERESTARTSYS)
+ return t;
+ return 0;
}
EXPORT_SYMBOL(wait_for_completion_interruptible);

2007-10-18 19:20:53

by Ingo Molnar

[permalink] [raw]
Subject: Re: wait_for_completion_interruptible() changes


* Andi Kleen <[email protected]> wrote:

> > I suspect this is caused by the recent completion refactoring?
>
> Yes. Here's a patch to fix it.
>
> Fix return value of wait_for_completion_interruptible()
>
> The recent w_f_c() changes broke the return value of
> wait_for_completion_interruptible(). Previously it returned 0 on
> success, now -1. Fix that.

argh. _Please_ be a bit more careful with cleanups.

applied.

Ingo