From 8d34694c1abf29df1f3c7317936b7e3e2e308d9b Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Mon, 8 Oct 2012 16:29:14 -0700 Subject: [PATCH] revert "mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages" 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 Signed-off-by: Mel Gorman Cc: Christoph Lameter Cc: Josh Boyer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mempolicy.c | 41 ++++++++++++++++++++++++----------------- 1 file changed, 24 insertions(+), 17 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 4ada3be6e252..92daa267baf2 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -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) @@ -655,23 +676,9 @@ 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); - if (err) - goto out; - } + err = policy_vma(vma, new_pol); + if (err) + goto out; } out: -- 2.20.1