+ mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch added to -mm tree

+ mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/userfaultfd: fix a few thp pmd missing uffd-wp bit
has been added to the -mm tree.  Its filename is
     mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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------------------------------------------------------
From: Peter Xu <peterx@redhat.com>
Subject: mm/userfaultfd: fix a few thp pmd missing uffd-wp bit

These include:

1. When remove migration pmd entry, should keep the uffd-wp bit from
   swap pte.  Note that we need to do this after setting write bit just in
   case we need to remove it.

2. When change huge pmd and convert write -> read migration entry,
   persist the same uffd-wp bit.

3. When convert pmd to swap entry, should drop the uffd-wp bit always.

Link: https://lkml.kernel.org/r/20210428225030.9708-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Wang Qing <wangqing@vivo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/swapops.h |    2 ++
 mm/huge_memory.c        |    4 ++++
 2 files changed, 6 insertions(+)

--- a/include/linux/swapops.h~mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit
+++ a/include/linux/swapops.h
@@ -258,6 +258,8 @@ static inline swp_entry_t pmd_to_swp_ent
 
 	if (pmd_swp_soft_dirty(pmd))
 		pmd = pmd_swp_clear_soft_dirty(pmd);
+	if (pmd_swp_uffd_wp(pmd))
+		pmd = pmd_swp_clear_uffd_wp(pmd);
 	arch_entry = __pmd_to_swp_entry(pmd);
 	return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
 }
--- a/mm/huge_memory.c~mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit
+++ a/mm/huge_memory.c
@@ -1823,6 +1823,8 @@ int change_huge_pmd(struct vm_area_struc
 			newpmd = swp_entry_to_pmd(entry);
 			if (pmd_swp_soft_dirty(*pmd))
 				newpmd = pmd_swp_mksoft_dirty(newpmd);
+			if (pmd_swp_uffd_wp(*pmd))
+				newpmd = pmd_swp_mkuffd_wp(newpmd);
 			set_pmd_at(mm, addr, pmd, newpmd);
 		}
 		goto unlock;
@@ -3234,6 +3236,8 @@ void remove_migration_pmd(struct page_vm
 		pmde = pmd_mksoft_dirty(pmde);
 	if (is_write_migration_entry(entry))
 		pmde = maybe_pmd_mkwrite(pmde, vma);
+	if (pmd_swp_uffd_wp(*pvmw->pmd))
+		pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde));
 
 	flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE);
 	if (PageAnon(new))
_

Patches currently in -mm which might be from peterx@redhat.com are

mm-hugetlb-fix-f_seal_future_write.patch
mm-hugetlb-fix-cow-where-page-writtable-in-child.patch
mm-gup_benchmark-support-threading.patch
userfaultfd-selftests-use-user-mode-only.patch
userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch
userfaultfd-selftests-dropping-verify-check-in-locking_thread.patch
userfaultfd-selftests-only-dump-counts-if-mode-enabled.patch
userfaultfd-selftests-unify-error-handling.patch
mm-thp-simplify-copying-of-huge-zero-page-pmd-when-fork.patch
mm-userfaultfd-fix-uffd-wp-special-cases-for-fork.patch
mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch
mm-userfaultfd-fail-uffd-wp-registeration-if-not-supported.patch
mm-pagemap-export-uffd-wp-protection-information.patch
userfaultfd-selftests-add-pagemap-uffd-wp-test.patch