mm,hwpoison: refactor madvise_inject_error

mainline inclusion
from linux-v5.10-rc1
commit dc7560b4
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4LE22
CVE: NA

--------------------------------

Make a proper if-else condition for {hard,soft}-offline.

[akpm: refactor comment]
Signed-off-by: NOscar Salvador <osalvador@suse.de>
Acked-by: NNaoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: NMa Wupeng <mawupeng1@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

mm/madvise.c

@@ -638,7 +638,6 @@ static long madvise_remove(struct vm_area_struct *vma,
 static int madvise_inject_error(int behavior,
 		unsigned long start, unsigned long end)
 {
-	struct page *page;
 	struct zone *zone;
 	unsigned int order;
 
@@ -647,6 +646,7 @@ static int madvise_inject_error(int behavior,
 
 
 	for (; start < end; start += PAGE_SIZE << order) {
+		struct page *page;
 		unsigned long pfn;
 		int ret;
 
@@ -669,25 +669,23 @@ static int madvise_inject_error(int behavior,
 
 		if (behavior == MADV_SOFT_OFFLINE) {
 			pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
-					pfn, start);
+				 pfn, start);
 
 			ret = soft_offline_page(page, MF_COUNT_INCREASED);
-			if (ret)
-				return ret;
-			continue;
+		} else {
+			pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
+				 pfn, start);
+			/*
+			 * Drop the page reference taken by
+			 * get_user_pages_fast(). In the absence of
+			 * MF_COUNT_INCREASED the memory_failure() routine is
+			 * responsible for pinning the page to prevent it
+			 * from being released back to the page allocator.
+			 */
+			put_page(page);
+			ret = memory_failure(pfn, 0);
 		}
 
-		pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
-				pfn, start);
-
-		/*
-		 * Drop the page reference taken by get_user_pages_fast(). In
-		 * the absence of MF_COUNT_INCREASED the memory_failure()
-		 * routine is responsible for pinning the page to prevent it
-		 * from being released back to the page allocator.
-		 */
-		put_page(page);
-		ret = memory_failure(pfn, 0);
 		if (ret)
 			return ret;
 	}