mm/hugetlb: convert get_hwpoison_huge_page() to folios

Straightforward conversion of get_hwpoison_huge_page() to
get_hwpoison_hugetlb_folio().  Reduces two references to a head page in
memory-failure.c

[arnd@arndb.de: fix get_hwpoison_hugetlb_folio() stub]
  Link: https://lkml.kernel.org/r/20230119111920.635260-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20230118174039.14247-1-sidhartha.kumar@oracle.comSigned-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/hugetlb.h

@@ -172,7 +172,7 @@ bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
 						long freed);
 int isolate_hugetlb(struct page *page, struct list_head *list);
-int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison);
+int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison);
 int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 				bool *migratable_cleared);
 void putback_active_hugepage(struct page *page);
@@ -418,7 +418,7 @@ static inline int isolate_hugetlb(struct page *page, struct list_head *list)
 	return -EBUSY;
 }
 
-static inline int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison)
+static inline int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison)
 {
 	return 0;
 }

mm/hugetlb.c

@@ -7268,18 +7268,18 @@ int isolate_hugetlb(struct page *page, struct list_head *list)
 	return ret;
 }
 
-int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison)
+int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison)
 {
 	int ret = 0;
 
 	*hugetlb = false;
 	spin_lock_irq(&hugetlb_lock);
-	if (PageHeadHuge(page)) {
+	if (folio_test_hugetlb(folio)) {
 		*hugetlb = true;
-		if (HPageFreed(page))
+		if (folio_test_hugetlb_freed(folio))
 			ret = 0;
-		else if (HPageMigratable(page) || unpoison)
-			ret = get_page_unless_zero(page);
+		else if (folio_test_hugetlb_migratable(folio) || unpoison)
+			ret = folio_try_get(folio);
 		else
 			ret = -EBUSY;
 	}

mm/memory-failure.c

@@ -1257,28 +1257,28 @@ static inline bool HWPoisonHandlable(struct page *page, unsigned long flags)
 
 static int __get_hwpoison_page(struct page *page, unsigned long flags)
 {
-	struct page *head = compound_head(page);
+	struct folio *folio = page_folio(page);
 	int ret = 0;
 	bool hugetlb = false;
 
-	ret = get_hwpoison_huge_page(head, &hugetlb, false);
+	ret = get_hwpoison_hugetlb_folio(folio, &hugetlb, false);
 	if (hugetlb)
 		return ret;
 
 	/*
-	 * This check prevents from calling get_page_unless_zero() for any
-	 * unsupported type of page in order to reduce the risk of unexpected
-	 * races caused by taking a page refcount.
+	 * This check prevents from calling folio_try_get() for any
+	 * unsupported type of folio in order to reduce the risk of unexpected
+	 * races caused by taking a folio refcount.
 	 */
-	if (!HWPoisonHandlable(head, flags))
+	if (!HWPoisonHandlable(&folio->page, flags))
 		return -EBUSY;
 
-	if (get_page_unless_zero(head)) {
-		if (head == compound_head(page))
+	if (folio_try_get(folio)) {
+		if (folio == page_folio(page))
 			return 1;
 
 		pr_info("%#lx cannot catch tail\n", page_to_pfn(page));
-		put_page(head);
+		folio_put(folio);
 	}
 
 	return 0;
@@ -1347,11 +1347,11 @@ static int get_any_page(struct page *p, unsigned long flags)
 
 static int __get_unpoison_page(struct page *page)
 {
-	struct page *head = compound_head(page);
+	struct folio *folio = page_folio(page);
 	int ret = 0;
 	bool hugetlb = false;
 
-	ret = get_hwpoison_huge_page(head, &hugetlb, true);
+	ret = get_hwpoison_hugetlb_folio(folio, &hugetlb, true);
 	if (hugetlb)
 		return ret;