They deal with wrapping correctly and are nicer to read.  Also make
jiffies-holding variables unsigned long.
Signed-off-by: NMarcelo Feitoza Parisi <marcelo@feitoza.com.br>
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>