x86-64, NUMA: Seperate out numa_alloc_distance() from numa_set_distance()

Alloc code is much bigger the distance setting.  Separate it out into
numa_alloc_distance() for readability.

-v2: Let alloc_numa_distance to return -ENOMEM on failing path,
     requested by tj.

-tj: Description update.  Minor tweaks including function name,
     location and return value check.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

arch/x86/mm/numa_64.c

@@ -401,19 +401,8 @@ void __init numa_reset_distance(void)
 	numa_distance = NULL;
 }
 
-/**
- * numa_set_distance - Set NUMA distance from one NUMA to another
- * @from: the 'from' node to set distance
- * @to: the 'to'  node to set distance
- * @distance: NUMA distance
- *
- * Set the distance from node @from to @to to @distance.  If distance table
- * doesn't exist, one which is large enough to accomodate all the currently
- * known nodes will be created.
- */
-void __init numa_set_distance(int from, int to, int distance)
+static int __init numa_alloc_distance(void)
 {
-	if (!numa_distance) {
 	nodemask_t nodes_parsed;
 	size_t size;
 	int i, j, cnt = 0;
@@ -427,14 +416,13 @@ void __init numa_set_distance(int from, int to, int distance)
 		cnt = i;
 	size = ++cnt * sizeof(numa_distance[0]);
 
-		phys = memblock_find_in_range(0,
-					      (u64)max_pfn_mapped << PAGE_SHIFT,
+	phys = memblock_find_in_range(0, (u64)max_pfn_mapped << PAGE_SHIFT,
 				      size, PAGE_SIZE);
 	if (phys == MEMBLOCK_ERROR) {
 		pr_warning("NUMA: Warning: can't allocate distance table!\n");
 		/* don't retry until explicitly reset */
 		numa_distance = (void *)1LU;
-			return;
+		return -ENOMEM;
 	}
 	memblock_x86_reserve_range(phys, phys + size, "NUMA DIST");
 
@@ -447,7 +435,24 @@ void __init numa_set_distance(int from, int to, int distance)
 			numa_distance[i * cnt + j] = i == j ?
 				LOCAL_DISTANCE : REMOTE_DISTANCE;
 	printk(KERN_DEBUG "NUMA: Initialized distance table, cnt=%d\n", cnt);
-	}
+
+	return 0;
+}
+
+/**
+ * numa_set_distance - Set NUMA distance from one NUMA to another
+ * @from: the 'from' node to set distance
+ * @to: the 'to'  node to set distance
+ * @distance: NUMA distance
+ *
+ * Set the distance from node @from to @to to @distance.  If distance table
+ * doesn't exist, one which is large enough to accomodate all the currently
+ * known nodes will be created.
+ */
+void __init numa_set_distance(int from, int to, int distance)
+{
+	if (!numa_distance && numa_alloc_distance() < 0)
+		return;
 
 	if (from >= numa_distance_cnt || to >= numa_distance_cnt) {
 		printk_once(KERN_DEBUG "NUMA: Debug: distance out of bound, from=%d to=%d distance=%d\n",