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Commit 8d34694c authored by KOSAKI Motohiro's avatar KOSAKI Motohiro Committed by Linus Torvalds
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revert "mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages" 



Commit 05f144a0 ("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: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1fb3f8ca

mm/mempolicy.c

+24 −17
Original line number Diff line number Diff line
@@ -607,6 +607,27 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end, 
	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)
@@ -655,24 +676,10 @@ static int mbind_range(struct mm_struct *mm, unsigned long start, 
			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);

		err = policy_vma(vma, new_pol);

		if (err)

			goto out;

	}

	}



 out:

	return err;