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-rw-r--r--include/linux/acpi.h23
1 files changed, 22 insertions, 1 deletions
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 9f70b7807d53..d661cd0ee64d 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -416,9 +416,30 @@ extern void acpi_osi_setup(char *str);
extern bool acpi_osi_is_win8(void);
#ifdef CONFIG_ACPI_NUMA
-int acpi_map_pxm_to_online_node(int pxm);
int acpi_map_pxm_to_node(int pxm);
int acpi_get_node(acpi_handle handle);
+
+/**
+ * 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.
+ */
+static inline int acpi_map_pxm_to_online_node(int pxm)
+{
+ int node = acpi_map_pxm_to_node(pxm);
+
+ return numa_map_to_online_node(node);
+}
#else
static inline int acpi_map_pxm_to_online_node(int pxm)
{