Re: cpumask: fix compat getaffinity

[Arnd Bergmann <arnd@arndb.de>]

On Tuesday 14 December 2010, Josh Hunt wrote:
> 
> I realize this thread is fairly old, but I have a question about this
> statement in the changelog:
> 
> > On NUMA systems with less than 32 possibly CPUs, the
> > current compat_sys_sched_getaffinity now returns '4'
> > instead of the actual NR_CPUS/8, which makes libnuma
> > bail out when parsing the cpumap.
> 
> This does not seem accurate, at least not on my system with NR_CPUS=32
> and nr_cpu_ids=8. The smallest value retlen will ever be set to is
> sizeof(long) which is 8 on most modern systems. This breaks the
> statement that this function will now return NR_CPUS/8.

Yes, I think the description is a bit misleading there.
The point was that it should return the number that the
sysfs files are based on, instead of the smallest multiple
of sizeof(compat_long) that can hold the installed CPUs.

	Arnd