| From 8d34694c1abf29df1f3c7317936b7e3e2e308d9b Mon Sep 17 00:00:00 2001 |
| From: KOSAKI Motohiro <kosaki.motohiro@gmail.com> |
| Date: Mon, 8 Oct 2012 16:29:14 -0700 |
| Subject: revert "mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages" |
| |
| From: KOSAKI Motohiro <kosaki.motohiro@gmail.com> |
| |
| commit 8d34694c1abf29df1f3c7317936b7e3e2e308d9b upstream. |
| |
| Commit 05f144a0d5c2 ("mm: mempolicy: Let vma_merge and vma_split handle |
| vma->vm_policy linkages") removed vma->vm_policy updates code but it is |
| the purpose of mbind_range(). Now, mbind_range() is virtually a no-op |
| and while it does not allow memory corruption it is not the right fix. |
| This patch is a revert. |
| |
| [mgorman@suse.de: Edited changelog] |
| Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
| Signed-off-by: Mel Gorman <mgorman@suse.de> |
| Cc: Christoph Lameter <cl@linux.com> |
| Cc: Josh Boyer <jwboyer@gmail.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/mempolicy.c | 41 ++++++++++++++++++++++++----------------- |
| 1 file changed, 24 insertions(+), 17 deletions(-) |
| |
| --- a/mm/mempolicy.c |
| +++ b/mm/mempolicy.c |
| @@ -606,6 +606,27 @@ check_range(struct mm_struct *mm, unsign |
| return first; |
| } |
| |
| +/* Apply policy to a single VMA */ |
| +static int policy_vma(struct vm_area_struct *vma, struct mempolicy *new) |
| +{ |
| + int err = 0; |
| + struct mempolicy *old = vma->vm_policy; |
| + |
| + pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n", |
| + vma->vm_start, vma->vm_end, vma->vm_pgoff, |
| + vma->vm_ops, vma->vm_file, |
| + vma->vm_ops ? vma->vm_ops->set_policy : NULL); |
| + |
| + if (vma->vm_ops && vma->vm_ops->set_policy) |
| + err = vma->vm_ops->set_policy(vma, new); |
| + if (!err) { |
| + mpol_get(new); |
| + vma->vm_policy = new; |
| + mpol_put(old); |
| + } |
| + return err; |
| +} |
| + |
| /* Step 2: apply policy to a range and do splits. */ |
| static int mbind_range(struct mm_struct *mm, unsigned long start, |
| unsigned long end, struct mempolicy *new_pol) |
| @@ -645,23 +666,9 @@ static int mbind_range(struct mm_struct |
| if (err) |
| goto out; |
| } |
| - |
| - /* |
| - * Apply policy to a single VMA. The reference counting of |
| - * policy for vma_policy linkages has already been handled by |
| - * vma_merge and split_vma as necessary. If this is a shared |
| - * policy then ->set_policy will increment the reference count |
| - * for an sp node. |
| - */ |
| - pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n", |
| - vma->vm_start, vma->vm_end, vma->vm_pgoff, |
| - vma->vm_ops, vma->vm_file, |
| - vma->vm_ops ? vma->vm_ops->set_policy : NULL); |
| - if (vma->vm_ops && vma->vm_ops->set_policy) { |
| - err = vma->vm_ops->set_policy(vma, new_pol); |
| - if (err) |
| - goto out; |
| - } |
| + err = policy_vma(vma, new_pol); |
| + if (err) |
| + goto out; |
| } |
| |
| out: |