[PATCH 1/3] mm: introduce vma_is_anonymous(vma) helper

Oleg Nesterov
2015-06-21T21:09:01Z

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 very accurate, say mmap_mem/VM_PFNMAP 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.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
include/linux/mm.h | 5 +++++
mm/memory.c | 13 ++++++-------
2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0755b9f..a0fe3d3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1225,6 +1225,11 @@ 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 || !vma->vm_ops->fault;
+}
+
static inline int stack_guard_page_start(struct vm_area_struct *vma,
unsigned long addr)
{
diff --git a/mm/memory.c b/mm/memory.c
index 22e037e..f50ed81 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3242,13 +3242,12 @@ static int handle_pte_fault(struct mm_struct *mm,
barrier();
if (!pte_present(entry)) {
if (pte_none(entry)) {
- if (vma->vm_ops) {
- if (likely(vma->vm_ops->fault))
- return do_fault(mm, vma, address, pte,
- pmd, flags, entry);
- }
- return do_anonymous_page(mm, vma, address,
- pte, pmd, flags);
+ if (vma_is_anonymous(vma))
+ return do_anonymous_page(mm, vma, address,
+ pte, pmd, flags);
+ else
+ return do_fault(mm, vma, address, pte, pmd,
+ flags, entry);
}
return do_swap_page(mm, vma, address,
pte, pmd, flags, entry);
--
1.5.5.1