mm: memory-failure: kill __soft_offline_page()

Squash the __soft_offline_page() into soft_offline_in_use_page() and kill
__soft_offline_page().

[wangkefeng.wang@huawei.com: update hpage when try_to_split_thp_page() succeeds]
  Link: https://lkml.kernel.org/r/20220830104654.28234-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20220819033402.156519-2-wangkefeng.wang@huawei.comSigned-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: NMiaohe Lin <linmiaohe@huawei.com>
Acked-by: NNaoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

mm/memory-failure.c

@@ -2432,11 +2432,11 @@ static bool isolate_page(struct page *page, struct list_head *pagelist)
 }
 
 /*
- * __soft_offline_page handles hugetlb-pages and non-hugetlb pages.
+ * soft_offline_in_use_page handles hugetlb-pages and non-hugetlb pages.
  * If the page is a non-dirty unmapped page-cache page, it simply invalidates.
  * If the page is mapped, it migrates the contents over.
  */
-static int __soft_offline_page(struct page *page)
+static int soft_offline_in_use_page(struct page *page)
 {
 	long ret = 0;
 	unsigned long pfn = page_to_pfn(page);
@@ -2449,6 +2449,14 @@ static int __soft_offline_page(struct page *page)
 		.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
 	};
 
+	if (!huge && PageTransHuge(hpage)) {
+		if (try_to_split_thp_page(page)) {
+			pr_info("soft offline: %#lx: thp split failed\n", pfn);
+			return -EBUSY;
+		}
+		hpage = page;
+	}
+
 	lock_page(page);
 	if (!PageHuge(page))
 		wait_on_page_writeback(page);
@@ -2498,19 +2506,6 @@ static int __soft_offline_page(struct page *page)
 	return ret;
 }
 
-static int soft_offline_in_use_page(struct page *page)
-{
-	struct page *hpage = compound_head(page);
-
-	if (!PageHuge(page) && PageTransHuge(hpage))
-		if (try_to_split_thp_page(page) < 0) {
-			pr_info("soft offline: %#lx: thp split failed\n",
-				page_to_pfn(page));
-			return -EBUSY;
-		}
-	return __soft_offline_page(page);
-}
-
 static void put_ref_page(struct page *page)
 {
 	if (page)