On Mon, 21 Nov 2011 19:48:32 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> >From 7c29389be2890c6b6934a80b4841d07a7014fe26 Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Date: Mon, 21 Nov 2011 19:45:27 +0900
> Subject: [PATCH] Fix virtual address handling in hugetlb fault
>
> handle_mm_fault() passes 'faulted' address to hugetlb_fault().
> Then, the address is not aligned to hugepage boundary.
>
> Most of functions for hugetlb pages are aware of that and
> calculate an alignment by itself. Some functions as copy_user_huge_page(),
> and clear_huge_page() doesn't handle alignment by themselves.
>
> This patch make hugeltb_fault() to calculate the alignment and pass
> aligned addresss (top address of a faulted hugepage) to functions.
>
Does this actually fix any known user-visible misbehaviour?
It sounds like the code is masking addresses in a lot of different
places. It would be better to do it once, at the top level. Perhaps
this patch makes some of the existing masking obsolete?
> index bb28a5f..af37337 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2629,6 +2629,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
> static DEFINE_MUTEX(hugetlb_instantiation_mutex);
> struct hstate *h = hstate_vma(vma);
>
> + address = address & huge_page_mask(h);
--- a/mm/hugetlb.c~mm-hugetlbc-fix-virtual-address-handling-in-hugetlb-fault-fix
+++ a/mm/hugetlb.c
@@ -2639,7 +2639,7 @@ int hugetlb_fault(struct mm_struct *mm,
static DEFINE_MUTEX(hugetlb_instantiation_mutex);
struct hstate *h = hstate_vma(vma);
- address = address & huge_page_mask(h);
+ address &= huge_page_mask(h);
ptep = huge_pte_offset(mm, address);
if (ptep) {
is a bit more readable, IMO.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>