In read_zero, we check for access_ok() once for the count bytes.  It is
unnecessarily checked again in clear_user.  Use __clear_user, which does
not check for access_ok().
Signed-off-by: NNikanth Karthikesan <knikanth@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>