mem-hotplug: introduce MMOP_OFFLINE to replace the hard coding -1

In store_mem_state(), we have:

  ...
  334         else if (!strncmp(buf, "offline", min_t(int, count, 7)))
  335                 online_type = -1;
  ...
  355         case -1:
  356                 ret = device_offline(&mem->dev);
  357                 break;
  ...

Here, "offline" is hard coded as -1.

This patch does the following renaming:

 ONLINE_KEEP     ->  MMOP_ONLINE_KEEP
 ONLINE_KERNEL   ->  MMOP_ONLINE_KERNEL
 ONLINE_MOVABLE  ->  MMOP_ONLINE_MOVABLE

and introduces MMOP_OFFLINE = -1 to avoid hard coding.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Hu Tao <hutao@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/memory.c

@@ -284,7 +284,7 @@ static int memory_subsys_online(struct device *dev)
 	 * attribute and need to set the online_type.
 	 */
 	if (mem->online_type < 0)
-		mem->online_type = ONLINE_KEEP;
+		mem->online_type = MMOP_ONLINE_KEEP;
 
 	ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
 
@@ -316,22 +316,22 @@ store_mem_state(struct device *dev,
 		return ret;
 
 	if (sysfs_streq(buf, "online_kernel"))
-		online_type = ONLINE_KERNEL;
+		online_type = MMOP_ONLINE_KERNEL;
 	else if (sysfs_streq(buf, "online_movable"))
-		online_type = ONLINE_MOVABLE;
+		online_type = MMOP_ONLINE_MOVABLE;
 	else if (sysfs_streq(buf, "online"))
-		online_type = ONLINE_KEEP;
+		online_type = MMOP_ONLINE_KEEP;
 	else if (sysfs_streq(buf, "offline"))
-		online_type = -1;
+		online_type = MMOP_OFFLINE;
 	else {
 		ret = -EINVAL;
 		goto err;
 	}
 
 	switch (online_type) {
-	case ONLINE_KERNEL:
-	case ONLINE_MOVABLE:
-	case ONLINE_KEEP:
+	case MMOP_ONLINE_KERNEL:
+	case MMOP_ONLINE_MOVABLE:
+	case MMOP_ONLINE_KEEP:
 		/*
 		 * mem->online_type is not protected so there can be a
 		 * race here.  However, when racing online, the first
@@ -342,7 +342,7 @@ store_mem_state(struct device *dev,
 		mem->online_type = online_type;
 		ret = device_online(&mem->dev);
 		break;
-	case -1:
+	case MMOP_OFFLINE:
 		ret = device_offline(&mem->dev);
 		break;
 	default:

include/linux/memory_hotplug.h

@@ -26,11 +26,12 @@ enum {
 	MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE = NODE_INFO,
 };
 
-/* Types for control the zone type of onlined memory */
+/* Types for control the zone type of onlined and offlined memory */
 enum {
-	ONLINE_KEEP,
-	ONLINE_KERNEL,
-	ONLINE_MOVABLE,
+	MMOP_OFFLINE = -1,
+	MMOP_ONLINE_KEEP,
+	MMOP_ONLINE_KERNEL,
+	MMOP_ONLINE_MOVABLE,
 };
 
 /*

mm/memory_hotplug.c

@@ -977,15 +977,18 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 	zone = page_zone(pfn_to_page(pfn));
 
 	ret = -EINVAL;
-	if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
+	if ((zone_idx(zone) > ZONE_NORMAL ||
+	    online_type == MMOP_ONLINE_MOVABLE) &&
 	    !can_online_high_movable(zone))
 		goto out;
 
-	if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
+	if (online_type == MMOP_ONLINE_KERNEL &&
+	    zone_idx(zone) == ZONE_MOVABLE) {
 		if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages))
 			goto out;
 	}
-	if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
+	if (online_type == MMOP_ONLINE_MOVABLE &&
+	    zone_idx(zone) == ZONE_MOVABLE - 1) {
 		if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages))
 			goto out;
 	}