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userfaultfd: remove WRITE_ONCE when setting folio->index during UFFDIO_MOVE

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When folio is moved with UFFDIO_MOVE it gets locked before the rmap and
index are modified.  Due to the folio lock being already held,
WRITE_ONCE() is not needed when setting the folio index.  Remove it.

Link: https://lkml.kernel.org/r/20240415020821.1152951-1-surenb@google.com
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Suren Baghdasaryan 2024-04-14 19:08:21 -07:00 committed by Andrew Morton
parent 231f8c7127
commit b5ba3a6427
2 changed files with 2 additions and 2 deletions
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2
mm/huge_memory.c
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@ -2200,7 +2200,7 @@ int move_pages_huge_pmd(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd, pm
}
folio_move_anon_rmap(src_folio, dst_vma);
WRITE_ONCE(src_folio->index, linear_page_index(dst_vma, dst_addr));
src_folio->index = linear_page_index(dst_vma, dst_addr);
_dst_pmd = mk_huge_pmd(&src_folio->page, dst_vma->vm_page_prot);
/* Follow mremap() behavior and treat the entry dirty after the move */

2
mm/userfaultfd.c
View file

@ -1026,7 +1026,7 @@ static int move_present_pte(struct mm_struct *mm,
}
folio_move_anon_rmap(src_folio, dst_vma);
WRITE_ONCE(src_folio->index, linear_page_index(dst_vma, dst_addr));
src_folio->index = linear_page_index(dst_vma, dst_addr);
orig_dst_pte = mk_pte(&src_folio->page, dst_vma->vm_page_prot);
/* Follow mremap() behavior and treat the entry dirty after the move */