From 4e55757f8febf883f1d42aeeb441ef2dbb577d20 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 8 Sep 2015 14:58:28 -0700 Subject: 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 Acked-by: Kirill A. Shutemov Cc: Andy Lutomirski Cc: Hugh Dickins Cc: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.16 as dependency of "mm/mincore.c: make mincore() more conservative"; adjusted context] Signed-off-by: Ben Hutchings (cherry picked from commit e3bcb8e29b639d822175be5cb1b8e6b124edf98e) --- include/linux/mm.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/mm.h') 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, -- cgit v1.2.3