[PATCH] Have x86 and x86_64 lll_futex_wake return the syscall error.

[Andreas Jaeger]

On 05/24/2013 11:53 PM, Carlos O'Donell wrote:
> It is very very possible that the futex syscall returns an
> error and that the caller of lll_futex_wake may want to
> look at that error and propagate the failure.
>
> In the current i386 and x86-64 implementations of pthread_once
> we don't currently check for a failure in lll_futex_wake
> but we *should* for the sake of correctness and robustness.
> It's this kind of problem which eventually results in
> hard to track down bugs in the nptl code.
>
> I first noticed this when I was testing removing the pthread_once
> assembly implementation for x86 and x86_64 and looking at the
> performance difference. Regardless of the results of that analysis,
> which isn't done, and which Torvald is now initially tackling as the
> pthread_once unification work[1], this is a good step forward.
>
> This patch is a first step and ensures that a status is returned
> for the lll_futex_wake call so we can detect failures.
>
> No regressions in either x86 or x86-64.
>
> OK to commit?

Yes, looks fine to me,

thanks,
Andreas
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