mm,hwpoison: refactor madvise_inject_error

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

Signed-off-by: Oscar Salvador <osalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Link: https://lkml.kernel.org/r/20200908075626.11976-3-osalvador@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/madvise.c

@@ -872,7 +872,6 @@ 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 long size;
 
@@ -882,6 +881,7 @@ static int madvise_inject_error(int behavior,
 
 	for (; start < end; start += size) {
 		unsigned long pfn;
+		struct page *page;
 		int ret;
 
 		ret = get_user_pages_fast(start, 1, 0, &page);
@@ -903,25 +903,21 @@ 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(pfn, 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;
 	}