+ revert-mm-migration-fix-the-foll_get-failure-on-following-huge-page.patch added to mm-unstable branch

+ revert-mm-migration-fix-the-foll_get-failure-on-following-huge-page.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: Revert "mm: migration: fix the FOLL_GET failure on following huge page"
has been added to the -mm mm-unstable branch.  Its filename is
     revert-mm-migration-fix-the-foll_get-failure-on-following-huge-page.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-mm-migration-fix-the-foll_get-failure-on-following-huge-page.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: Baolin Wang <baolin.wang@linux.alibaba.com>
Subject: Revert "mm: migration: fix the FOLL_GET failure on following huge page"
Date: Wed, 9 Nov 2022 16:40:27 +0800

Revert commit 831568214883 ("mm: migration: fix the FOLL_GET failure on
following huge page"), since after commit 1a6baaa0db73 ("s390/hugetlb:
switch to generic version of follow_huge_pud()") and commit 57a196a58421
("hugetlb: simplify hugetlb handling in follow_page_mask") were merged,
now all the following huge page routines can support FOLL_GET operation.

Link: https://lkml.kernel.org/r/496786039852aba90ffa68f10d0df3f4236a990b.1667983080.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Haiyue Wang <haiyue.wang@intel.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/migrate.c |   10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

--- a/mm/migrate.c~revert-mm-migration-fix-the-foll_get-failure-on-following-huge-page
+++ a/mm/migrate.c
@@ -1899,7 +1899,6 @@ static void do_pages_stat_array(struct m
 
 	for (i = 0; i < nr_pages; i++) {
 		unsigned long addr = (unsigned long)(*pages);
-		unsigned int foll_flags = FOLL_DUMP;
 		struct vm_area_struct *vma;
 		struct page *page;
 		int err = -EFAULT;
@@ -1908,12 +1907,8 @@ static void do_pages_stat_array(struct m
 		if (!vma)
 			goto set_status;
 
-		/* Not all huge page follow APIs support 'FOLL_GET' */
-		if (!is_vm_hugetlb_page(vma))
-			foll_flags |= FOLL_GET;
-
 		/* FOLL_DUMP to ignore special (like zero) pages */
-		page = follow_page(vma, addr, foll_flags);
+		page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP);
 
 		err = PTR_ERR(page);
 		if (IS_ERR(page))
@@ -1926,8 +1921,7 @@ static void do_pages_stat_array(struct m
 		if (!is_zone_device_page(page))
 			err = page_to_nid(page);
 
-		if (foll_flags & FOLL_GET)
-			put_page(page);
+		put_page(page);
 set_status:
 		*status = err;
 
_

Patches currently in -mm which might be from baolin.wang@linux.alibaba.com are

revert-mm-migration-fix-the-foll_get-failure-on-following-huge-page.patch