mbind: Restrict nodes to the currently allowed cpuset

Currently one can specify an arbitrary node mask to mbind that includes nodes
not allowed. If that is done with an interleave policy then we will go around
all the nodes. Those outside of the currently allowed cpuset will be redirected
to the border nodes. Interleave will then create imbalances at the borders
of the cpuset.

This patch restricts the nodes to the currently allowed cpuset.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.19-mm1/mm/mempolicy.c
===================================================================
--- linux-2.6.19-mm1.orig/mm/mempolicy.c	2006-12-11 19:00:38.224610647 -0800
+++ linux-2.6.19-mm1/mm/mempolicy.c	2006-12-13 11:13:10.175294067 -0800
@@ -882,6 +882,7 @@ asmlinkage long sys_mbind(unsigned long 
 	int err;
 
 	err = get_nodes(&nodes, nmask, maxnode);
+	nodes_and(nodes, nodes, current->mems_allowed);
 	if (err)
 		return err;
 	return do_mbind(start, len, mode, &nodes, flags);