[PATCH] Fix get_nodes() mask miscalculation

[PATCH] Fix get_nodes() mask miscalculation

It appears there is a nodemask miscalculation in the get_nodes() function
in mm/mempolicy.c.  This bug has two effects:

1. It is impossible to specify a length 1 nodemask.
2. It is impossible to specify a nodemask containing the last node.

The following patch has been confirmed to solve both problems.

Signed-off-by: Brent Casavant <bcasavan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>