[CRIU] [PATCH 3/7] Skip adding PROT_READ to non-PROT_READ mappings

[Dmitry Safonov]

On 8/25/19 2:58 AM, Abhishek Dubey wrote:
[..]
> -	pargs->add_prot = PROT_READ;
> -	ret = compel_rpc_call_sync(PARASITE_CMD_MPROTECT_VMAS, ctl);
> -	if (ret) {
> -		pr_err("Can't dump unprotect vmas with parasite\n");
> -		return ret;
> -	}
> +	if (!mdc->pre_dump || opts.pre_dump_mode == PRE_DUMP_SPLICE) {
> +		pargs->add_prot = PROT_READ;
> +		ret = compel_rpc_call_sync(PARASITE_CMD_MPROTECT_VMAS, ctl);
> +		if (ret) {
> +			pr_err("Can't dump unprotect vmas with parasite\n");
> +			return ret;
> +		}

Nit: could we separate it into:
static int parasite_mprotect_vmas(struct parasite_ctl *ctl, int prot)
{
     struct parasite_dump_pages_args *pargs;
     int ret;

     ret = compel_rpc_call_sync(PARASITE_CMD_MPROTECT_VMAS, ctl);
     /*  ... */
}

>  
> -	if (fault_injected(FI_DUMP_PAGES)) {
> -		pr_err("fault: Dump VMA pages failure!\n");
> -		return -1;
> +		if (fault_injected(FI_DUMP_PAGES)) {
> +			pr_err("fault: Dump VMA pages failure!\n");
> +			return -1;
> +		}

Hmm, I might be mistaken, but it may make sense to leave it outside "if"?

>  	}
>  
>  	ret = __parasite_dump_pages_seized(item, pargs, vma_area_list, mdc, ctl);
> @@ -574,10 +607,12 @@ int parasite_dump_pages_seized(struct pstree_item *item,
>  		return ret;
>  	}
>  
> -	pargs->add_prot = 0;
> -	if (compel_rpc_call_sync(PARASITE_CMD_MPROTECT_VMAS, ctl)) {
> -		pr_err("Can't rollback unprotected vmas with parasite\n");
> -		ret = -1;
> +	if (!mdc->pre_dump || opts.pre_dump_mode == PRE_DUMP_SPLICE) {
> +		pargs->add_prot = 0;
> +		if (compel_rpc_call_sync(PARASITE_CMD_MPROTECT_VMAS, ctl)) {
> +			pr_err("Can't rollback unprotected vmas with parasite\n");
> +			ret = -1;
> +		}

And reuse it here?

Thanks,
          Dmitry