The patch titled
Subject: mm: introduce vma_is_anonymous(vma) helper
has been added to the -mm tree. Its filename is
mm-introduce-vma_is_anonymousvma-helper.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-introduce-vma_is_anonymousvma-helper.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-introduce-vma_is_anonymousvma-helper.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: 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 grep-friendly.
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: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 5 +++++
mm/memory.c | 8 ++++----
2 files changed, 9 insertions(+), 4 deletions(-)
diff -puN include/linux/mm.h~mm-introduce-vma_is_anonymousvma-helper include/linux/mm.h
--- a/include/linux/mm.h~mm-introduce-vma_is_anonymousvma-helper
+++ a/include/linux/mm.h
@@ -1233,6 +1233,11 @@ static inline int vma_growsdown(struct v
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)
{
diff -puN mm/memory.c~mm-introduce-vma_is_anonymousvma-helper mm/memory.c
--- a/mm/memory.c~mm-introduce-vma_is_anonymousvma-helper
+++ a/mm/memory.c
@@ -3267,12 +3267,12 @@ static int handle_pte_fault(struct mm_st
barrier();
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);
+ else
return do_fault(mm, vma, address, pte, pmd,
flags, entry);
-
- return do_anonymous_page(mm, vma, address, pte, pmd,
- flags);
}
return do_swap_page(mm, vma, address,
pte, pmd, flags, entry);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
mm-cleaning-per-architecture-mm-hook-header-files.patch
mremap-dont-leak-new_vma-if-f_op-mremap-fails.patch
mm-move-mremap-from-file_operations-to-vm_operations_struct.patch
mremap-dont-do-mm_populatenew_addr-on-failure.patch
mremap-dont-do-uneccesary-checks-if-new_len-==-old_len.patch
mremap-simplify-the-overlap-check-in-mremap_to.patch
mm-introduce-vma_is_anonymousvma-helper.patch
mmap-fix-the-usage-of-vm_pgoff-in-special_mapping-paths.patch
mremap-fix-the-wrong-vma-vm_file-check-in-copy_vma.patch
kmod-bunch-of-internal-functions-renames.patch
kmod-add-up-to-date-explanations-on-the-purpose-of-each-asynchronous-levels.patch
kmod-remove-unecessary-explicit-wide-cpu-affinity-setting.patch
linux-next.patch
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