Commit b5330628 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds

mm: introduce vma_is_anonymous(vma) helper

special_mapping_fault() is absolutely broken.  It seems it was always
wrong, but this didn't matter until vdso/vvar started to use more than
one page.

And after this change vma_is_anonymous() becomes really trivial, it
simply checks vm_ops == NULL.  However, I do think the helper makes
sense.  There are a lot of ->vm_ops != NULL checks, the helper makes the
caller's code more understandable (self-documented) and this is more

This patch (of 3):

Preparation.  Add the new simple helper, vma_is_anonymous(vma), and change
handle_pte_fault() to use it.  It will have more users.

The name is not accurate, say a hpet_mmap()'ed vma is not anonymous.
Perhaps it should be named vma_has_fault() instead.  But it matches the
logic in mmap.c/memory.c (see next changes).  "True" just means that a
page fault will use do_anonymous_page().
Signed-off-by: default avatarOleg Nesterov <>
Acked-by: default avatarKirill A. Shutemov <>
Cc: Andy Lutomirski <>
Cc: Hugh Dickins <>
Cc: Pavel Emelyanov <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent af8713b7
......@@ -1260,6 +1260,11 @@ static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
static inline bool vma_is_anonymous(struct vm_area_struct *vma)
return !vma->vm_ops;
static inline int stack_guard_page_start(struct vm_area_struct *vma,
unsigned long addr)
......@@ -3267,12 +3267,12 @@ static int handle_pte_fault(struct mm_struct *mm,
if (!pte_present(entry)) {
if (pte_none(entry)) {
if (vma->vm_ops)
if (vma_is_anonymous(vma))
return do_anonymous_page(mm, vma, address,
pte, pmd, flags);
return do_fault(mm, vma, address, pte, pmd,
flags, entry);
return do_anonymous_page(mm, vma, address, pte, pmd,
return do_swap_page(mm, vma, address,
pte, pmd, flags, entry);
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