2 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index 1a9ef3e627d1..5dce5c21822c 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -352,6 +352,7 @@ extern nodemask_t node_possible_map;
 #define node_possible(node)     node_isset((node), node_possible_map)
 #define first_online_node       first_node(node_online_map)
 #define next_online_node(nid)   next_node((nid), node_online_map)
+int highest_possible_node_id(void);
 #else
 #define num_online_nodes()      1
 #define num_possible_nodes()    1
@@ -359,6 +360,7 @@ extern nodemask_t node_possible_map;
 #define node_possible(node)     ((node) == 0)
 #define first_online_node       0
 #define next_online_node(nid)   (MAX_NUMNODES)
+#define highest_possible_node_id()      0
 #endif
 
 #define any_online_node(mask)                   \
diff --git a/lib/cpumask.c b/lib/cpumask.c
index 3a67dc5ada7d..7a2a73f88d59 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -43,3 +43,19 @@ int __any_online_cpu(const cpumask_t *mask)
         return cpu;
 }
 EXPORT_SYMBOL(__any_online_cpu);
+
+#if MAX_NUMNODES > 1
+/*
+ * Find the highest possible node id.
+ */
+int highest_possible_node_id(void)
+{
+        unsigned int node;
+        unsigned int highest = 0;
+
+        for_each_node_mask(node, node_possible_map)
+                highest = node;
+        return highest;
+}
+EXPORT_SYMBOL(highest_possible_node_id);
+#endif