Commit ab941e0f authored May 11, 2010 by Naoya Horiguchi Committed by Linus Torvalds May 11, 2010

rmap: remove anon_vma check in page_address_in_vma()



Currently page_address_in_vma() compares vma->anon_vma and
page_anon_vma(page) for parameter check, but in 2.6.34 a vma can have
multiple anon_vmas with anon_vma_chain, so current check does not work.
(For anonymous page shared by multiple processes, some verified (page,vma)
pairs return -EFAULT wrongly.)

We can go to checking all anon_vmas in the "same_vma" chain, but it needs
to meet lock requirement.  Instead, we can remove anon_vma check safely
because page_address_in_vma() assumes that page and vma are already
checked to belong to the identical process.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 4a6018f7

mm/rmap.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -336,14 +336,13 @@ vma_address(struct page page, struct vm_area_struct vma)

		/*
		* At what user virtual address is page expected in vma?
		* checking that the page matches the vma.
		* Caller should check the page is actually part of the vma.
		*/
		unsigned long page_address_in_vma(struct page page, struct vm_area_struct vma)
		{
		if (PageAnon(page)) {
		if (vma->anon_vma != page_anon_vma(page))
		return -EFAULT;
		} else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
		if (PageAnon(page))
		;
		else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
		if (!vma->vm_file \|\|
		vma->vm_file->f_mapping != page->mapping)
		return -EFAULT;

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