x86, mm: Split out split_mem_range from init_memory_mapping

So make init_memory_mapping smaller and readable.

-v2: use 0 instead of nr_range as input parameter found by Yasuaki Ishimatsu.

Suggested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-3-git-send-email-yinghai@kernel.org
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/mm/init.c

@@ -146,25 +146,13 @@ static int __meminit save_mr(struct map_range *mr, int nr_range,
 	return nr_range;
 }
 
-/*
- * Setup the direct mapping of the physical memory at PAGE_OFFSET.
- * This runs before bootmem is initialized and gets pages directly from
- * the physical memory. To access them they are temporarily mapped.
- */
-unsigned long __init_refok init_memory_mapping(unsigned long start,
-					       unsigned long end)
+static int __meminit split_mem_range(struct map_range *mr, int nr_range,
+				     unsigned long start,
+				     unsigned long end)
 {
 	unsigned long start_pfn, end_pfn;
-	unsigned long ret = 0;
 	unsigned long pos;
-	struct map_range mr[NR_RANGE_MR];
-	int nr_range, i;
-
-	printk(KERN_INFO "init_memory_mapping: [mem %#010lx-%#010lx]\n",
-	       start, end - 1);
-
-	memset(mr, 0, sizeof(mr));
-	nr_range = 0;
+	int i;
 
 	/* head if not big page alignment ? */
 	start_pfn = start >> PAGE_SHIFT;
@@ -258,6 +246,27 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 			(mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
 			 (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
 
+	return nr_range;
+}
+
+/*
+ * Setup the direct mapping of the physical memory at PAGE_OFFSET.
+ * This runs before bootmem is initialized and gets pages directly from
+ * the physical memory. To access them they are temporarily mapped.
+ */
+unsigned long __init_refok init_memory_mapping(unsigned long start,
+					       unsigned long end)
+{
+	struct map_range mr[NR_RANGE_MR];
+	unsigned long ret = 0;
+	int nr_range, i;
+
+	pr_info("init_memory_mapping: [mem %#010lx-%#010lx]\n",
+	       start, end - 1);
+
+	memset(mr, 0, sizeof(mr));
+	nr_range = split_mem_range(mr, 0, start, end);
+
 	/*
 	 * Find space for the kernel direct mapping tables.
 	 *