The follow patch special cases the NR_CPUS <= BITS_PER_COMPAT_LONG case.
Without this patch, a 32bit task would be required to have a 64bit
cpumask no matter what value of NR_CPUS are used.

With this patch a compat long sized bitmask is allowed if NR_CPUS is
small enough to fit within it.

Of course applications should be using the glibc wrappers that use an
opaque cpu_mask_t type, but there could be older applications using the
syscalls directly.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>