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

Patch series "convert hugepage memory failure functions to folios".

This series contains a 1:1 straightforward page to folio conversion for
memory failure functions which deal with huge pages.  I renamed a few
functions to fit with how other folio operating functions are named. 
These include:

hugetlb_clear_page_hwpoison -> folio_clear_hugetlb_hwpoison
free_raw_hwp_pages -> folio_free_raw_hwp
__free_raw_hwp_pages -> __folio_free_raw_hwp
hugetlb_set_page_hwpoison -> folio_set_hugetlb_hwpoison

The goal of this series was to reduce users of the hugetlb specific page
flag macros which take in a page so users are protected by the compiler to
make sure they are operating on a head page.


This patch (of 8):

Use a folio throughout the function rather than using a head page.  This
also reduces the users of the page version of hugetlb specific page flags.

Link: https://lkml.kernel.org/r/20230112204608.80136-2-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

@@ -1807,20 +1807,20 @@ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 				 bool *migratable_cleared)
 {
 	struct page *page = pfn_to_page(pfn);
-	struct page *head = compound_head(page);
+	struct folio *folio = page_folio(page);
 	int ret = 2;	/* fallback to normal page handling */
 	bool count_increased = false;
 
-	if (!PageHeadHuge(head))
+	if (!folio_test_hugetlb(folio))
 		goto out;
 
 	if (flags & MF_COUNT_INCREASED) {
 		ret = 1;
 		count_increased = true;
-	} else if (HPageFreed(head)) {
+	} else if (folio_test_hugetlb_freed(folio)) {
 		ret = 0;
-	} else if (HPageMigratable(head)) {
-		ret = get_page_unless_zero(head);
+	} else if (folio_test_hugetlb_migratable(folio)) {
+		ret = folio_try_get(folio);
 		if (ret)
 			count_increased = true;
 	} else {
@@ -1829,24 +1829,24 @@ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 			goto out;
 	}
 
-	if (hugetlb_set_page_hwpoison(head, page)) {
+	if (hugetlb_set_page_hwpoison(&folio->page, page)) {
 		ret = -EHWPOISON;
 		goto out;
 	}
 
 	/*
-	 * Clearing HPageMigratable for hwpoisoned hugepages to prevent them
+	 * Clearing hugetlb_migratable for hwpoisoned hugepages to prevent them
 	 * from being migrated by memory hotremove.
 	 */
-	if (count_increased && HPageMigratable(head)) {
-		ClearHPageMigratable(head);
+	if (count_increased && folio_test_hugetlb_migratable(folio)) {
+		folio_clear_hugetlb_migratable(folio);
 		*migratable_cleared = true;
 	}
 
 	return ret;
 out:
 	if (count_increased)
-		put_page(head);
+		folio_put(folio);
 	return ret;
 }