In preemptible kernel will report BUG: using smp_processor_id() in
preemptible, so use boot_cpu_data instead of current_cpu_data.

discussion in :
http://lkml.org/lkml/2007/7/25/32Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
CC: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>