Re: x86, x32: Correct invalid use of user timespec in the kernel

[H. Peter Anvin]

On 01/31/2014 10:45 AM, Linus Torvalds wrote:
> On Fri, Jan 31, 2014 at 10:06 AM, H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> wrote:
>>
>> My feeling is that {get,put}_compat_timespec() should at the very least
>> have leading underscores to flag it as a low-level function, but better
>> suggestions would be appreciated.
> 
> Why not just remove it entirely, and change all users to
> compat_[get|set]_timespec (same for timeval etc, of course).
> 
> After all, compat_*_time*() does fall back cleanly for non-x32 cases.
> And sure, maybe that particular code is never *needed* for x32
> support, but the overhead is generally zero (since in most cases X32
> isn't even configured), or very low anyway. So the upside of having
> two subtly incompatible interfaces is very dubious, no?
> 

As they both seem to be out of line, I would think so.  More than half
of the use cases are in kernel/compat.c where we could use a
double-underscore inline version if we really care -- it would probably
be a net win in terms of performance.

There are only 25 call sites in the kernel of
'(get|put)_compat_time(val|spec)' and that includes the ones inside the
larger functions.

	-hpa

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