* [merged mm-stable] mm-hugetlb-hook-page-faults-for-uffd-write-protection.patch removed from -mm tree
@ 2022-05-13 19:21 Andrew Morton
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From: Andrew Morton @ 2022-05-13 19:21 UTC (permalink / raw)
To: mm-commits, willy, rppt, nadav.amit, mike.kravetz, kirill,
jglisse, hughd, david, axelrasmussen, apopple, aarcange, peterx,
akpm
The quilt patch titled
Subject: mm/hugetlb: hook page faults for uffd write protection
has been removed from the -mm tree. Its filename was
mm-hugetlb-hook-page-faults-for-uffd-write-protection.patch
This patch was dropped because it was merged into the mm-stable branch\nof git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Peter Xu <peterx@redhat.com>
Subject: mm/hugetlb: hook page faults for uffd write protection
Hook up hugetlbfs_fault() with the capability to handle userfaultfd-wp
faults.
We do this slightly earlier than hugetlb_cow() so that we can avoid taking
some extra locks that we definitely don't need.
Link: https://lkml.kernel.org/r/20220405014901.14590-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/hugetlb.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
--- a/mm/hugetlb.c~mm-hugetlb-hook-page-faults-for-uffd-write-protection
+++ a/mm/hugetlb.c
@@ -5737,6 +5737,26 @@ vm_fault_t hugetlb_fault(struct mm_struc
if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
goto out_ptl;
+ /* Handle userfault-wp first, before trying to lock more pages */
+ if (userfaultfd_wp(vma) && huge_pte_uffd_wp(huge_ptep_get(ptep)) &&
+ (flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
+ struct vm_fault vmf = {
+ .vma = vma,
+ .address = haddr,
+ .real_address = address,
+ .flags = flags,
+ };
+
+ spin_unlock(ptl);
+ if (pagecache_page) {
+ unlock_page(pagecache_page);
+ put_page(pagecache_page);
+ }
+ mutex_unlock(&hugetlb_fault_mutex_table[hash]);
+ i_mmap_unlock_read(mapping);
+ return handle_userfault(&vmf, VM_UFFD_WP);
+ }
+
/*
* hugetlb_wp() requires page locks of pte_page(entry) and
* pagecache_page, so here we need take the former one
_
Patches currently in -mm which might be from peterx@redhat.com are
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2022-05-13 19:21 [merged mm-stable] mm-hugetlb-hook-page-faults-for-uffd-write-protection.patch removed from -mm tree Andrew Morton
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