+ mm-hwpoison-make-__page_handle_poison-returns-int.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm, hwpoison: make __page_handle_poison returns int
has been added to the -mm mm-unstable branch.  Its filename is
     mm-hwpoison-make-__page_handle_poison-returns-int.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hwpoison-make-__page_handle_poison-returns-int.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Naoya Horiguchi <naoya.horiguchi@nec.com>
Subject: mm, hwpoison: make __page_handle_poison returns int
Date: Thu, 2 Jun 2022 14:06:29 +0900

__page_handle_poison() returns bool that shows whether
take_page_off_buddy() has passed or not now.  But we will want to
distinguish another case of "dissolve has passed but taking off failed" by
its return value.  So change the type of the return value.  No functional
change.

Link: https://lkml.kernel.org/r/20220602050631.771414-4-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory-failure.c |   17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

--- a/mm/memory-failure.c~mm-hwpoison-make-__page_handle_poison-returns-int
+++ a/mm/memory-failure.c
@@ -69,7 +69,13 @@ int sysctl_memory_failure_recovery __rea
 
 atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0);
 
-static bool __page_handle_poison(struct page *page)
+/*
+ * Return values:
+ *   1:   the page is dissolved (if needed) and taken off from buddy,
+ *   0:   the page is dissolved (if needed) and not taken off from buddy,
+ *   < 0: failed to dissolve.
+ */
+static int __page_handle_poison(struct page *page)
 {
 	int ret;
 
@@ -79,7 +85,7 @@ static bool __page_handle_poison(struct
 		ret = take_page_off_buddy(page);
 	zone_pcp_enable(page_zone(page));
 
-	return ret > 0;
+	return ret;
 }
 
 static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release)
@@ -89,7 +95,7 @@ static bool page_handle_poison(struct pa
 		 * Doing this check for free pages is also fine since dissolve_free_huge_page
 		 * returns 0 for non-hugetlb pages as well.
 		 */
-		if (!__page_handle_poison(page))
+		if (__page_handle_poison(page) <= 0)
 			/*
 			 * We could fail to take off the target page from buddy
 			 * for example due to racy page allocation, but that's
@@ -1046,7 +1052,7 @@ static int me_huge_page(struct page_stat
 		 * subpages.
 		 */
 		put_page(hpage);
-		if (__page_handle_poison(p)) {
+		if (__page_handle_poison(p) > 0) {
 			page_ref_inc(p);
 			res = MF_RECOVERED;
 		}
@@ -1596,8 +1602,7 @@ retry:
 	 */
 	if (res == 0) {
 		unlock_page(head);
-		res = MF_FAILED;
-		if (__page_handle_poison(p)) {
+		if (__page_handle_poison(p) > 0) {
 			page_ref_inc(p);
 			res = MF_RECOVERED;
 		}
_

Patches currently in -mm which might be from naoya.horiguchi@nec.com are

mm-hwpoison-hugetlb-introduce-subpage_index_hwpoison-to-save-raw-error-page.patch
mmhwpoison-set-pg_hwpoison-for-busy-hugetlb-pages.patch
mm-hwpoison-make-__page_handle_poison-returns-int.patch
mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage.patch
mm-hwpoison-enable-memory-error-handling-on-1gb-hugepage.patch