memory-failure: do code refactor of soft_offline_page()

There are too many return points randomly intermingled with some "goto
done" return points.  So adjust the function structure, one for the
success path, the other for the failure path.  Use atomic_long_inc
instead of atomic_long_add.

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory-failure.c

@@ -1421,12 +1421,13 @@ static int soft_offline_huge_page(struct page *page, int flags)
 
 	if (PageHWPoison(hpage)) {
 		pr_info("soft offline: %#lx hugepage already poisoned\n", pfn);
-		return -EBUSY;
+		ret = -EBUSY;
+		goto out;
 	}
 
 	ret = get_any_page(page, pfn, flags);
 	if (ret < 0)
-		return ret;
+		goto out;
 	if (ret == 0)
 		goto done;
 
@@ -1437,14 +1438,14 @@ static int soft_offline_huge_page(struct page *page, int flags)
 	if (ret) {
 		pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
 			pfn, ret, page->flags);
-		return ret;
+		goto out;
 	}
 done:
 	/* keep elevated page count for bad page */
 	atomic_long_add(1 << compound_trans_order(hpage), &mce_bad_pages);
 	set_page_hwpoison_huge_page(hpage);
 	dequeue_hwpoisoned_huge_page(hpage);
-
+out:
 	return ret;
 }
 
@@ -1476,24 +1477,28 @@ int soft_offline_page(struct page *page, int flags)
 	unsigned long pfn = page_to_pfn(page);
 	struct page *hpage = compound_trans_head(page);
 
-	if (PageHuge(page))
-		return soft_offline_huge_page(page, flags);
+	if (PageHuge(page)) {
+		ret = soft_offline_huge_page(page, flags);
+		goto out;
+	}
 	if (PageTransHuge(hpage)) {
 		if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
 			pr_info("soft offline: %#lx: failed to split THP\n",
 				pfn);
-			return -EBUSY;
+			ret = -EBUSY;
+			goto out;
 		}
 	}
 
 	if (PageHWPoison(page)) {
 		pr_info("soft offline: %#lx page already poisoned\n", pfn);
-		return -EBUSY;
+		ret = -EBUSY;
+		goto out;
 	}
 
 	ret = get_any_page(page, pfn, flags);
 	if (ret < 0)
-		return ret;
+		goto out;
 	if (ret == 0)
 		goto done;
 
@@ -1512,14 +1517,15 @@ int soft_offline_page(struct page *page, int flags)
 		 */
 		ret = get_any_page(page, pfn, 0);
 		if (ret < 0)
-			return ret;
+			goto out;
 		if (ret == 0)
 			goto done;
 	}
 	if (!PageLRU(page)) {
 		pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
 			pfn, page->flags);
-		return -EIO;
+		ret = -EIO;
+		goto out;
 	}
 
 	/*
@@ -1575,12 +1581,12 @@ int soft_offline_page(struct page *page, int flags)
 			pfn, ret, page_count(page), page->flags);
 	}
 	if (ret)
-		return ret;
+		goto out;
 
 done:
 	/* keep elevated page count for bad page */
-	atomic_long_add(1, &mce_bad_pages);
+	atomic_long_inc(&mce_bad_pages);
 	SetPageHWPoison(page);
-
+out:
 	return ret;
 }