Re: [PATCH 3/5] mm: Rework return value for copy_one_pte()

Oleg Nesterov
2020-09-22T10:08:58Z

On 09/21, Peter Xu wrote:
>
> @@ -866,13 +877,18 @@ static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
> pte_unmap_unlock(orig_dst_pte, dst_ptl);
> cond_resched();
>
> - if (entry.val) {
> - if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
> + switch (copy_ret) {
> + case COPY_MM_SWAP_CONT:
> + if (add_swap_count_continuation(data.entry, GFP_KERNEL) < 0)
> return -ENOMEM;
> - progress = 0;
> + break;

Note that you didn't clear copy_ret, it is still COPY_MM_SWAP_CONT,

> + default:
> + break;
> }
> +
> if (addr != end)
> goto again;

After that the main loop can stop again because of need_resched(), and
in this case add_swap_count_continuation(data.entry) will be called again?

Oleg.