Re: [patch 8/8] x86/vdso: Implement __vdso_futex_robust_try_unlock()

[Florian Weimer]

* Thomas Gleixner:

> Arguably this could be avoided by providing separate functions and making
> the IP range for the quick check in the exit to user path cover the whole
> text section which contains the two functions. But that's not a win at all
> because:
>
>    1) User space needs to handle the two variants instead of just
>       relying on a bit which can be saved in the mutex at
>       initialization time.

I'm pretty sure that on the user-space side, we wouldn't have
cross-word-size operations (e.g., 64-bit code working on both 64-bit and
32-bit robust mutexes).  Certainly not within libcs.  The other point
about complexity is of course still valid.

Thanks,
Florian