From 9c67a20704e763f9cb8cd262c3e45de7bd2816bc Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Fri, 16 Dec 2022 10:52:29 -0500 Subject: mm/hugetlb: introduce hugetlb_walk() huge_pte_offset() is the main walker function for hugetlb pgtables. The name is not really representing what it does, though. Instead of renaming it, introduce a wrapper function called hugetlb_walk() which will use huge_pte_offset() inside. Assert on the locks when walking the pgtable. Note, the vma lock assertion will be a no-op for private mappings. Document the last special case in the page_vma_mapped_walk() path where we don't need any more lock to call hugetlb_walk(). Taking vma lock there is not needed because either: (1) potential callers of hugetlb pvmw holds i_mmap_rwsem already (from one rmap_walk()), or (2) the caller will not walk a hugetlb vma at all so the hugetlb code path not reachable (e.g. in ksm or uprobe paths). It's slightly implicit for future page_vma_mapped_walk() callers on that lock requirement. But anyway, when one day this rule breaks, one will get a straightforward warning in hugetlb_walk() with lockdep, then there'll be a way out. [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/20221216155229.2043750-1-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: Mike Kravetz Reviewed-by: John Hubbard Reviewed-by: David Hildenbrand Cc: Andrea Arcangeli Cc: James Houghton Cc: Jann Horn Cc: Miaohe Lin Cc: Muchun Song Cc: Nadav Amit Cc: Rik van Riel Signed-off-by: Andrew Morton --- mm/pagewalk.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'mm/pagewalk.c') diff --git a/mm/pagewalk.c b/mm/pagewalk.c index d98564a7be57..cb23f8a15c13 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -305,13 +305,11 @@ static int walk_hugetlb_range(unsigned long addr, unsigned long end, hugetlb_vma_lock_read(vma); do { next = hugetlb_entry_end(h, addr, end); - pte = huge_pte_offset(walk->mm, addr & hmask, sz); - + pte = hugetlb_walk(vma, addr & hmask, sz); if (pte) err = ops->hugetlb_entry(pte, hmask, addr, next, walk); else if (ops->pte_hole) err = ops->pte_hole(addr, next, -1, walk); - if (err) break; } while (addr = next, addr != end); -- cgit v1.2.3