[CRIU] [RFC PATCH 08/16] criu: lazy_pages: drop find_vmas

[Pavel Emelyanov]

Some comment would be nice :)

On 09/27/2016 04:42 PM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt at linux.vnet.ibm.com>
> ---
>  criu/uffd.c | 85 ++++++++-----------------------------------------------------
>  1 file changed, 10 insertions(+), 75 deletions(-)
> 
> diff --git a/criu/uffd.c b/criu/uffd.c
> index 9a44807..c0c1349 100644
> --- a/criu/uffd.c
> +++ b/criu/uffd.c
> @@ -323,8 +323,6 @@ out:
>  	return -1;
>  }
>  
> -static int find_vmas(struct lazy_pages_info *lpi);
> -
>  static int update_lazy_iovecs(struct lazy_pages_info *lpi, unsigned long addr,
>  			       int len)
>  {
> @@ -441,13 +439,22 @@ static struct lazy_pages_info *ud_open(int client)
>  	uffd_flags = fcntl(lpi->uffd, F_GETFD, NULL);
>  	pr_debug("uffd_flags are 0x%x\n", uffd_flags);
>  
> +	ret = open_page_read(lpi->pid, &lpi->pr, PR_TASK);
> +	if (ret <= 0) {
> +		ret = -1;
> +		goto out;
> +	}
> +
>  	/*
>  	 * Find the memory pages belonging to the restored process
>  	 * so that it is trackable when all pages have been transferred.
>  	 */
> -	if ((lpi->total_pages = find_vmas(lpi)) == -1)
> +	lpi->total_pages = collect_lazy_iovecs(lpi);
> +	if (lpi->total_pages < 0)
>  		goto out;
>  
> +	pr_debug("Found %ld pages to be handled by UFFD\n", lpi->total_pages);
> +
>  	hlist_add_head(&lpi->hash, &lpi_hash[lpi->uffd % LPI_HASH_SIZE]);
>  
>  	ret = collect_lazy_iovecs(lpi);
> @@ -614,78 +621,6 @@ static int handle_regular_pages(struct lazy_pages_info *lpi, void *dest,
>  	return 0;
>  }
>  
> -/*
> - *  Setting up criu infrastructure and scan for VMAs.
> - */
> -static int find_vmas(struct lazy_pages_info *lpi)
> -{
> -	struct cr_img *img;
> -	int ret;
> -	struct vm_area_list vmas;
> -	int vn = 0;
> -	struct rst_info *ri;
> -	struct pstree_item *item = pstree_item_by_virt(lpi->pid);
> -
> -	BUG_ON(!item);
> -
> -	vm_area_list_init(&vmas);
> -
> -	ri = rsti(item);
> -	if (!ri)
> -		return -1;
> -
> -	img = open_image(CR_FD_MM, O_RSTR, lpi->pid);
> -	if (!img)
> -		return -1;
> -
> -	ret = pb_read_one_eof(img, &ri->mm, PB_MM);
> -	close_image(img);
> -	if (ret == -1)
> -		return -1;
> -
> -	pr_debug("Found %zd VMAs in image\n", ri->mm->n_vmas);
> -
> -	while (vn < ri->mm->n_vmas) {
> -		struct vma_area *vma;
> -
> -		ret = -1;
> -		vma = alloc_vma_area();
> -		if (!vma)
> -			goto out;
> -
> -		ret = 0;
> -		ri->vmas.nr++;
> -		vma->e = ri->mm->vmas[vn++];
> -
> -		list_add_tail(&vma->list, &ri->vmas.h);
> -
> -		if (vma_area_is_private(vma, kdat.task_size)) {
> -			vmas.priv_size += vma_area_len(vma);
> -			if (vma->e->flags & MAP_GROWSDOWN)
> -				vmas.priv_size += PAGE_SIZE;
> -		}
> -
> -		pr_info("vma 0x%"PRIx64" 0x%"PRIx64"\n", vma->e->start, vma->e->end);
> -	}
> -
> -	ret = open_page_read(lpi->pid, &lpi->pr, PR_TASK);
> -	if (ret <= 0) {
> -		ret = -1;
> -		goto out;
> -	}
> -
> -	ret = collect_lazy_iovecs(lpi);
> -	if (ret < 0) {
> -		pr_err("collect_lazy_iovecs=%d\n", ret);
> -		goto out;
> -	}
> -
> -	pr_debug("Found %d pages to be handled by UFFD\n", ret);
> -
> -out:
> -	return ret;
> -}
> -
>  static int handle_user_fault(struct lazy_pages_info *lpi, void *dest)
>  {
>  	struct uffd_msg msg;
>