mm/memory-failure: convert unpoison_memory() to folios

Use a folio inside unpoison_memory which replaces a compound_head() call
with a call to page_folio().

Link: https://lkml.kernel.org/r/20230112204608.80136-9-sidhartha.kumar@oracle.comSigned-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memory-failure.c

@@ -2335,7 +2335,6 @@ core_initcall(memory_failure_init);
  */
 int unpoison_memory(unsigned long pfn)
 {
-	struct page *page;
 	struct folio *folio;
 	struct page *p;
 	int ret = -EBUSY;
@@ -2348,7 +2347,6 @@ int unpoison_memory(unsigned long pfn)
 		return -ENXIO;
 
 	p = pfn_to_page(pfn);
-	page = compound_head(p);
 	folio = page_folio(p);
 
 	mutex_lock(&mf_mutex);
@@ -2360,31 +2358,31 @@ int unpoison_memory(unsigned long pfn)
 		goto unlock_mutex;
 	}
 
-	if (!PageHWPoison(p)) {
+	if (!folio_test_hwpoison(folio)) {
 		unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n",
 				 pfn, &unpoison_rs);
 		goto unlock_mutex;
 	}
 
-	if (page_count(page) > 1) {
+	if (folio_ref_count(folio) > 1) {
 		unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n",
 				 pfn, &unpoison_rs);
 		goto unlock_mutex;
 	}
 
-	if (page_mapped(page)) {
+	if (folio_mapped(folio)) {
 		unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n",
 				 pfn, &unpoison_rs);
 		goto unlock_mutex;
 	}
 
-	if (page_mapping(page)) {
+	if (folio_mapping(folio)) {
 		unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n",
 				 pfn, &unpoison_rs);
 		goto unlock_mutex;
 	}
 
-	if (PageSlab(page) || PageTable(page) || PageReserved(page))
+	if (folio_test_slab(folio) || PageTable(&folio->page) || folio_test_reserved(folio))
 		goto unlock_mutex;
 
 	ret = get_hwpoison_page(p, MF_UNPOISON);
@@ -2397,7 +2395,7 @@ int unpoison_memory(unsigned long pfn)
 				goto unlock_mutex;
 			}
 		}
-		ret = TestClearPageHWPoison(page) ? 0 : -EBUSY;
+		ret = folio_test_clear_hwpoison(folio) ? 0 : -EBUSY;
 	} else if (ret < 0) {
 		if (ret == -EHWPOISON) {
 			ret = put_page_back_buddy(p) ? 0 : -EBUSY;
@@ -2410,14 +2408,14 @@ int unpoison_memory(unsigned long pfn)
 			count = folio_free_raw_hwp(folio, false);
 			if (count == 0) {
 				ret = -EBUSY;
-				put_page(page);
+				folio_put(folio);
 				goto unlock_mutex;
 			}
 		}
 
-		put_page(page);
+		folio_put(folio);
 		if (TestClearPageHWPoison(p)) {
-			put_page(page);
+			folio_put(folio);
 			ret = 0;
 		}
 	}