arch/x86/mm/srat: Skip NUMA_NO_NODE while parsing SLIT

When ACPI SLIT table has an I/O locality (i.e. a locality
unique to an I/O device), numa_set_distance() emits this warning
message:

 NUMA: Warning: node ids are out of bound, from=-1 to=-1 distance=10

acpi_numa_slit_init() calls numa_set_distance() with
pxm_to_node(), which assumes that all localities have been
parsed with SRAT previously.  SRAT does not list I/O localities,
where as SLIT lists all localities including I/Os.  Hence,
pxm_to_node() returns NUMA_NO_NODE (-1) for an I/O locality.

I/O localities are not supported and are ignored today, but emitting
such warning message leads to unnecessary confusion.

Change acpi_numa_slit_init() to avoid calling
numa_set_distance() with NUMA_NO_NODE.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/n/tip-dSvpjjvp8aMzs1ybkftxohlh@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/mm/srat.c

@@ -42,15 +42,25 @@ static __init inline int srat_disabled(void)
 	return acpi_numa < 0;
 }
 
-/* Callback for SLIT parsing */
+/*
+ * Callback for SLIT parsing.  pxm_to_node() returns NUMA_NO_NODE for
+ * I/O localities since SRAT does not list them.  I/O localities are
+ * not supported at this point.
+ */
 void __init acpi_numa_slit_init(struct acpi_table_slit *slit)
 {
 	int i, j;
 
-	for (i = 0; i < slit->locality_count; i++)
-		for (j = 0; j < slit->locality_count; j++)
+	for (i = 0; i < slit->locality_count; i++) {
+		if (pxm_to_node(i) == NUMA_NO_NODE)
+			continue;
+		for (j = 0; j < slit->locality_count; j++) {
+			if (pxm_to_node(j) == NUMA_NO_NODE)
+				continue;
 			numa_set_distance(pxm_to_node(i), pxm_to_node(j),
 				slit->entry[slit->locality_count * i + j]);
+		}
+	}
 }
 
 /* Callback for Proximity Domain -> x2APIC mapping */