Operation of rep movsb instruction handles zero byte copy. As pointed out by
Linus, there is no need to check zero size in kernel. Removing this redundant
check saves a few cycles in copy user functions.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1384634221-6006-1-git-send-email-fenghua.yu@intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>