diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2015-09-08 14:58:28 -0700 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2019-07-18 20:48:31 +0200 |
| commit | 4e55757f8febf883f1d42aeeb441ef2dbb577d20 (patch) | |
| tree | 7e2914ae9dd9eed0408676db5b1d1c158b69b29c | |
| parent | a4fa84611dab6dd6b69f8e2acfe28cb59b89573f (diff) | |
mm: introduce vma_is_anonymous(vma) helper
commit b5330628546616af14ff23075fbf8d4ad91f6e25 upstream.
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().
Change-Id: I024c69016c5125b6f40e990a2f63c6630f641b28
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.16 as dependency of "mm/mincore.c: make mincore() more
conservative"; adjusted context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from commit e3bcb8e29b639d822175be5cb1b8e6b124edf98e)
| -rw-r--r-- | include/linux/mm.h | 5 | ||||
| -rw-r--r-- | mm/memory.c | 7 |
2 files changed, 9 insertions, 3 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index c1fab7973..740a1f7d3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1120,6 +1120,11 @@ int clear_page_dirty_for_io(struct page *page); extern struct task_struct *task_of_stack(struct task_struct *task, struct vm_area_struct *vma, bool in_group); +static inline bool vma_is_anonymous(struct vm_area_struct *vma) +{ + return !vma->vm_ops; +} + extern unsigned long move_page_tables(struct vm_area_struct *vma, unsigned long old_addr, struct vm_area_struct *new_vma, unsigned long new_addr, unsigned long len, diff --git a/mm/memory.c b/mm/memory.c index 12d825704..e3255d0be 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3710,11 +3710,12 @@ int handle_pte_fault(struct mm_struct *mm, entry = *pte; 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_linear_fault(mm, vma, address, pte, pmd, flags, entry); - return do_anonymous_page(mm, vma, address, - pte, pmd, flags); } if (pte_file(entry)) return do_nonlinear_fault(mm, vma, address, |