On 12/1/21 15:30, Liam Howlett wrote:
> From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
>
> Remove a use of the vm_next list by doing the initial lookup with the
> VMA iterator and then using it to find the next entry.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> fs/exec.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/fs/exec.c b/fs/exec.c
> index fee18b63ed35..f033745c148a 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -680,6 +680,8 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
> unsigned long length = old_end - old_start;
> unsigned long new_start = old_start - shift;
> unsigned long new_end = old_end - shift;
> + VMA_ITERATOR(vmi, mm, new_start);
> + struct vm_area_struct *next;
> struct mmu_gather tlb;
>
> BUG_ON(new_start > new_end);
> @@ -688,7 +690,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
> * ensure there are no vmas between where we want to go
> * and where we are
> */
> - if (vma != find_vma(mm, new_start))
> + if (vma != vma_next(&vmi))
> return -EFAULT;
>
> /*
> @@ -707,12 +709,13 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
>
> lru_add_drain();
> tlb_gather_mmu(&tlb, mm);
> + next = vma_next(&vmi);
> if (new_end > old_start) {
> /*
> * when the old and new regions overlap clear from new_end.
> */
> free_pgd_range(&tlb, new_end, old_end, new_end,
> - vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING);
> + next ? next->vm_start : USER_PGTABLES_CEILING);
> } else {
> /*
> * otherwise, clean from old_start; this is done to not touch
> @@ -721,7 +724,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
> * for the others its just a little faster.
> */
> free_pgd_range(&tlb, old_start, old_end, new_end,
> - vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING);
> + next ? next->vm_start : USER_PGTABLES_CEILING);
> }
> tlb_finish_mmu(&tlb);
>
