SWP_TYPE_SHIFT     21 include/linux/swapops.h #define SWP_OFFSET_MASK(e)	((1UL << SWP_TYPE_SHIFT(e)) - 1)
SWP_TYPE_SHIFT     30 include/linux/swapops.h 	ret.val = (type << SWP_TYPE_SHIFT(ret)) |
SWP_TYPE_SHIFT     41 include/linux/swapops.h 	return (entry.val >> SWP_TYPE_SHIFT(entry));