mm/hwpoison: introduce num_poisoned_pages wrappers

num_poisoned_pages counter will be changed outside mm/memory-failure.c
by a subsequent patch, so this patch prepares wrappers to manipulate it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Tested-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 5420d38..393ea13 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1121,7 +1121,7 @@
 		nr_pages = 1 << compound_order(hpage);
 	else /* normal page or thp */
 		nr_pages = 1;
-	atomic_long_add(nr_pages, &num_poisoned_pages);
+	num_poisoned_pages_add(nr_pages);
 
 	/*
 	 * We need/can do nothing about count=0 pages.
@@ -1149,7 +1149,7 @@
 			if (PageHWPoison(hpage)) {
 				if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
 				    || (p != hpage && TestSetPageHWPoison(hpage))) {
-					atomic_long_sub(nr_pages, &num_poisoned_pages);
+					num_poisoned_pages_sub(nr_pages);
 					unlock_page(hpage);
 					return 0;
 				}
@@ -1173,7 +1173,7 @@
 			else
 				pr_err("MCE: %#lx: thp split failed\n", pfn);
 			if (TestClearPageHWPoison(p))
-				atomic_long_sub(nr_pages, &num_poisoned_pages);
+				num_poisoned_pages_sub(nr_pages);
 			put_hwpoison_page(p);
 			return -EBUSY;
 		}
@@ -1233,14 +1233,14 @@
 	 */
 	if (!PageHWPoison(p)) {
 		printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn);
-		atomic_long_sub(nr_pages, &num_poisoned_pages);
+		num_poisoned_pages_sub(nr_pages);
 		unlock_page(hpage);
 		put_hwpoison_page(hpage);
 		return 0;
 	}
 	if (hwpoison_filter(p)) {
 		if (TestClearPageHWPoison(p))
-			atomic_long_sub(nr_pages, &num_poisoned_pages);
+			num_poisoned_pages_sub(nr_pages);
 		unlock_page(hpage);
 		put_hwpoison_page(hpage);
 		return 0;
@@ -1469,7 +1469,7 @@
 			return 0;
 		}
 		if (TestClearPageHWPoison(p))
-			atomic_long_dec(&num_poisoned_pages);
+			num_poisoned_pages_dec();
 		pr_info("MCE: Software-unpoisoned free page %#lx\n", pfn);
 		return 0;
 	}
@@ -1483,7 +1483,7 @@
 	 */
 	if (TestClearPageHWPoison(page)) {
 		pr_info("MCE: Software-unpoisoned page %#lx\n", pfn);
-		atomic_long_sub(nr_pages, &num_poisoned_pages);
+		num_poisoned_pages_sub(nr_pages);
 		freeit = 1;
 		if (PageHuge(page))
 			clear_page_hwpoison_huge_page(page);
@@ -1619,11 +1619,10 @@
 		if (PageHuge(page)) {
 			set_page_hwpoison_huge_page(hpage);
 			dequeue_hwpoisoned_huge_page(hpage);
-			atomic_long_add(1 << compound_order(hpage),
-					&num_poisoned_pages);
+			num_poisoned_pages_add(1 << compound_order(hpage));
 		} else {
 			SetPageHWPoison(page);
-			atomic_long_inc(&num_poisoned_pages);
+			num_poisoned_pages_inc();
 		}
 	}
 	return ret;
@@ -1662,7 +1661,7 @@
 		put_hwpoison_page(page);
 		pr_info("soft_offline: %#lx: invalidated\n", pfn);
 		SetPageHWPoison(page);
-		atomic_long_inc(&num_poisoned_pages);
+		num_poisoned_pages_inc();
 		return 0;
 	}
 
@@ -1683,7 +1682,7 @@
 					page_is_file_cache(page));
 		list_add(&page->lru, &pagelist);
 		if (!TestSetPageHWPoison(page))
-			atomic_long_inc(&num_poisoned_pages);
+			num_poisoned_pages_dec();
 		ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
 					MIGRATE_SYNC, MR_MEMORY_FAILURE);
 		if (ret) {
@@ -1699,7 +1698,7 @@
 			if (ret > 0)
 				ret = -EIO;
 			if (TestClearPageHWPoison(page))
-				atomic_long_dec(&num_poisoned_pages);
+				num_poisoned_pages_dec();
 		}
 	} else {
 		pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n",
@@ -1765,11 +1764,10 @@
 		if (PageHuge(page)) {
 			set_page_hwpoison_huge_page(hpage);
 			if (!dequeue_hwpoisoned_huge_page(hpage))
-				atomic_long_add(1 << compound_order(hpage),
-					&num_poisoned_pages);
+				num_poisoned_pages_add(1 << compound_order(hpage));
 		} else {
 			if (!TestSetPageHWPoison(page))
-				atomic_long_inc(&num_poisoned_pages);
+				num_poisoned_pages_inc();
 		}
 	}
 	return ret;