As described in a previous patch and documented in mm/filemap.h,
copy_from_user_inatomic* shouldn't zero out the tail of the buffer after an
incomplete copy.

This patch implements that change for i386.

For the _nocache version, a new __copy_user_intel_nocache is defined similar
to copy_user_zeroio_intel_nocache, and this is ultimately used for the copy.

For the regular version, __copy_from_user_ll_nozero is defined which uses
__copy_user and __copy_user_intel - the later needs casts to reposition the
__user annotations.

If copy_from_user_atomic is given a constant length of 1, 2, or 4, then we do
still zero the destintion on failure.  This didn't seem worth the effort of
fixing as the places where it is used really don't care.

Signed-off-by: Neil Brown <neilb@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>