+/**
+ * acpi_map_pxm_to_online_node - Map proximity ID to online node
+ * @pxm: ACPI proximity ID
+ *
+ * This is similar to acpi_map_pxm_to_node(), but always returns an online
+ * node. When the mapped node from a given proximity ID is offline, it
+ * looks up the node distance table and returns the nearest online node.
+ *
+ * ACPI device drivers, which are called after the NUMA initialization has
+ * completed in the kernel, can call this interface to obtain their device
+ * NUMA topology from ACPI tables. Such drivers do not have to deal with
+ * offline nodes. A node may be offline when a device proximity ID is
+ * unique, SRAT memory entry does not exist, or NUMA is disabled, ex.
+ * "numa=off" on x86.
+ */
+int acpi_map_pxm_to_online_node(int pxm)
+{
+ int node, n, dist, min_dist;
+
+ node = acpi_map_pxm_to_node(pxm);
+
+ if (node == NUMA_NO_NODE)
+ node = 0;
+
+ if (!node_online(node)) {
+ min_dist = INT_MAX;
+ for_each_online_node(n) {
+ dist = node_distance(node, n);
+ if (dist < min_dist) {
+ min_dist = dist;
+ node = n;
+ }
+ }
+ }
+
+ return node;
+}
+EXPORT_SYMBOL(acpi_map_pxm_to_online_node);
+