From: Simon Derr <Simon.Derr@bull.net>

Add a `needs_read_fill' field in sysfs_buffer so that reading after a write in
a sysfs file returns valid data.

(instead of the data that have been written, that may be invalid or at the
wrong offset)
Signed-off-by: Simon Derr <simon.derr@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>