On Wed, 7 Mar 2012, Bob Liu wrote:
> There are multi place do the same check, using find_mergeable_vma() to
> replace.
>
> Signed-off-by: Bob Liu <lliubbo@xxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
> ---
> mm/ksm.c | 34 +++++++++++++++++++---------------
> 1 files changed, 19 insertions(+), 15 deletions(-)
>
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 1925ffb..3a00767 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -375,6 +375,20 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
> return (ret & VM_FAULT_OOM) ? -ENOMEM : 0;
> }
>
> +static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm,
> + unsigned long addr)
> +{
> + struct vm_area_struct *vma;
> + if (ksm_test_exit(mm))
> + return NULL;
> + vma = find_vma(mm, addr);
> + if (!vma || vma->vm_start > addr)
> + return NULL;
> + if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
> + return NULL;
> + return vma;
> +}
> +
> static void break_cow(struct rmap_item *rmap_item)
> {
> struct mm_struct *mm = rmap_item->mm;
> @@ -388,15 +402,9 @@ static void break_cow(struct rmap_item *rmap_item)
> put_anon_vma(rmap_item->anon_vma);
>
> down_read(&mm->mmap_sem);
> - if (ksm_test_exit(mm))
> - goto out;
> - vma = find_vma(mm, addr);
> - if (!vma || vma->vm_start > addr)
> - goto out;
> - if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
> - goto out;
> - break_ksm(vma, addr);
> -out:
> + vma = find_mergeable_vma(mm, addr);
> + if (vma)
> + break_ksm(vma, addr);
> up_read(&mm->mmap_sem);
> }
>
> @@ -422,12 +430,8 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
> struct page *page;
>
> down_read(&mm->mmap_sem);
> - if (ksm_test_exit(mm))
> - goto out;
> - vma = find_vma(mm, addr);
> - if (!vma || vma->vm_start > addr)
> - goto out;
> - if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
> + vma = find_mergeable_vma(mm, addr);
> + if (!vma)
> goto out;
>
> page = follow_page(vma, addr, FOLL_GET);
> --
> 1.7.0.4
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