x86-64, NUMA: Trivial changes to prepare for emulation updates

* Separate out numa_add_memblk_to() from numa_add_memblk() so that
  different numa_meminfo can be used.

* Rename cmdline to emu_cmdline.

* Drop @start/last_pfn from numa_emulation() and use max_pfn directly.

This patch doesn't introduce any behavior change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/mm/numa_64.c

@@ -193,10 +193,9 @@ static void * __init early_node_mem(int nodeid, unsigned long start,
 	return NULL;
 }
 
-int __init numa_add_memblk(int nid, u64 start, u64 end)
+static int __init numa_add_memblk_to(int nid, u64 start, u64 end,
+				     struct numa_meminfo *mi)
 {
-	struct numa_meminfo *mi = &numa_meminfo;
-
 	/* ignore zero length blks */
 	if (start == end)
 		return 0;
@@ -227,6 +226,11 @@ static void __init numa_remove_memblk_from(int idx, struct numa_meminfo *mi)
 		(mi->nr_blks - idx) * sizeof(mi->blk[0]));
 }
 
+int __init numa_add_memblk(int nid, u64 start, u64 end)
+{
+	return numa_add_memblk_to(nid, start, end, &numa_meminfo);
+}
+
 /* Initialize bootmem allocator for a node */
 void __init
 setup_node_bootmem(int nodeid, unsigned long start, unsigned long end)
@@ -539,11 +543,11 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
 /* Numa emulation */
 static struct bootnode nodes[MAX_NUMNODES] __initdata;
 static struct bootnode physnodes[MAX_NUMNODES] __cpuinitdata;
-static char *cmdline __initdata;
+static char *emu_cmdline __initdata;
 
 void __init numa_emu_cmdline(char *str)
 {
-	cmdline = str;
+	emu_cmdline = str;
 }
 
 int __init find_node_by_addr(unsigned long addr)
@@ -861,12 +865,10 @@ static int __init split_nodes_size_interleave(u64 addr, u64 max_addr, u64 size)
  * Sets up the system RAM area from start_pfn to last_pfn according to the
  * numa=fake command-line option.
  */
-static int __init numa_emulation(unsigned long start_pfn,
-			unsigned long last_pfn, int acpi, int amd)
+static int __init numa_emulation(int acpi, int amd)
 {
 	static struct numa_meminfo ei __initdata;
-	u64 addr = start_pfn << PAGE_SHIFT;
-	u64 max_addr = last_pfn << PAGE_SHIFT;
+	const u64 max_addr = max_pfn << PAGE_SHIFT;
 	int num_nodes;
 	int i;
 
@@ -875,16 +877,16 @@ static int __init numa_emulation(unsigned long start_pfn,
 	 * the fixed node size.  Otherwise, if it is just a single number N,
 	 * split the system RAM into N fake nodes.
 	 */
-	if (strchr(cmdline, 'M') || strchr(cmdline, 'G')) {
+	if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
 		u64 size;
 
-		size = memparse(cmdline, &cmdline);
-		num_nodes = split_nodes_size_interleave(addr, max_addr, size);
+		size = memparse(emu_cmdline, &emu_cmdline);
+		num_nodes = split_nodes_size_interleave(0, max_addr, size);
 	} else {
 		unsigned long n;
 
-		n = simple_strtoul(cmdline, NULL, 0);
-		num_nodes = split_nodes_interleave(addr, max_addr, n);
+		n = simple_strtoul(emu_cmdline, NULL, 0);
+		num_nodes = split_nodes_interleave(0, max_addr, n);
 	}
 
 	if (num_nodes < 0)
@@ -916,7 +918,7 @@ static int __init numa_emulation(unsigned long start_pfn,
 	init_memory_mapping_high();
 	for_each_node_mask(i, node_possible_map)
 		setup_node_bootmem(i, nodes[i].start, nodes[i].end);
-	setup_physnodes(addr, max_addr);
+	setup_physnodes(0, max_addr);
 	fake_physnodes(acpi, amd, num_nodes);
 	numa_init_array();
 	numa_emu_dist = true;
@@ -972,7 +974,7 @@ void __init initmem_init(void)
 			continue;
 #ifdef CONFIG_NUMA_EMU
 		setup_physnodes(0, max_pfn << PAGE_SHIFT);
-		if (cmdline && !numa_emulation(0, max_pfn, i == 0, i == 1))
+		if (emu_cmdline && !numa_emulation(i == 0, i == 1))
 			return;
 		setup_physnodes(0, max_pfn << PAGE_SHIFT);
 		nodes_clear(node_possible_map);