+ mm-gup-remove-foll_migration-fix.patch added to mm-unstable branch

+ mm-gup-remove-foll_migration-fix.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm-gup-remove-foll_migration-fix
has been added to the -mm mm-unstable branch.  Its filename is
     mm-gup-remove-foll_migration-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-gup-remove-foll_migration-fix.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: Andrew Morton <akpm@linux-foundation.org>
Subject: mm-gup-remove-foll_migration-fix
Date: Fri Oct 21 03:04:50 PM PDT 2022

fix merge snafu

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/gup.c |   24 ++----------------------
 1 file changed, 2 insertions(+), 22 deletions(-)

--- a/mm/gup.c~mm-gup-remove-foll_migration-fix
+++ a/mm/gup.c
@@ -643,28 +643,8 @@ static struct page *follow_pmd_mask(stru
 	pmdval = READ_ONCE(*pmd);
 	if (pmd_none(pmdval))
 		return no_page_table(vma, flags);
-retry:
-	if (!pmd_present(pmdval)) {
-		/*
-		 * Should never reach here, if thp migration is not supported;
-		 * Otherwise, it must be a thp migration entry.
-		 */
-		VM_BUG_ON(!thp_migration_supported() ||
-				  !is_pmd_migration_entry(pmdval));
-
-		if (likely(!(flags & FOLL_MIGRATION)))
-			return no_page_table(vma, flags);
-
-		pmd_migration_entry_wait(mm, pmd);
-		pmdval = READ_ONCE(*pmd);
-		/*
-		 * MADV_DONTNEED may convert the pmd to null because
-		 * mmap_lock is held in read mode
-		 */
-		if (pmd_none(pmdval))
-			return no_page_table(vma, flags);
-		goto retry;
-	}
+	if (!pmd_present(pmdval))
+		return no_page_table(vma, flags);
 	if (likely(!(pmd_trans_huge(pmdval) || pmd_devmap(pmdval))))
 		return follow_page_pte(vma, address, pmd, flags);
 
_

Patches currently in -mm which might be from akpm@linux-foundation.org are

ipc-msgc-fix-percpu_counter-use-after-free.patch
fs-ext4-superc-remove-unused-deprecated_msg.patch
mm-memremap_pages-replace-zone_device_page_init-with-pgmap_request_folios-fix.patch
mm-hugetlb-convert-free_huge_page-to-folios-fix.patch
vmalloc-add-reviewers-for-vmalloc-code-checkpatch-fixes.patch
mm-gup-remove-foll_migration-fix.patch
powerpc-ptrace-user_regset_copyin_ignore-always-returns-0-fix.patch
minmax-sanity-check-constant-bounds-when-clamping-checkpatch-fixes.patch
minmax-sanity-check-constant-bounds-when-clamping-checkpatch-fixes-fix.patch
proc-report-open-files-as-size-in-stat-for-proc-pid-fd-v3-fix.patch