[CRIU] [PATCH 1/6] Skip adding PROT_READ flag

[abhishek dubey]

On 30/07/19 10:05 AM, Andrei Vagin wrote:
> On Thu, Jul 25, 2019 at 06:43:10AM +0530, Abhishek Dubey wrote:
>> skip adding PROT_READ protection to the regions lacking
>> it for new pre-dump implementation
> You need to describe why we need this changes. Nobody knows this new
> pre-dump implementation yet.

Sure! I will be more descriptive in commit message.

I will cover detailed working of new implementation and process_vm_readv 
in cover letter.

Can the commit message point to content of cover letter?

>
>> Signed-off-by: Abhishek Dubey <dubeyabhishek777 at gmail.com>
>> ---
>>   criu/mem.c | 30 +++++++++++++++++-------------
>>   1 file changed, 17 insertions(+), 13 deletions(-)
>>
>> diff --git a/criu/mem.c b/criu/mem.c
>> index de66a62..a7e8d0b 100644
>> --- a/criu/mem.c
>> +++ b/criu/mem.c
>> @@ -530,16 +530,18 @@ int parasite_dump_pages_seized(struct pstree_item *item,
>>   	 * Afterwards -- reprotect memory back.
>>   	 */
>>   
>> -	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) {
>> +		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 (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;
>> +		}
>>   	}
>>   
>>   	ret = __parasite_dump_pages_seized(item, pargs, vma_area_list, mdc, ctl);
>> @@ -549,10 +551,12 @@ 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) {
>> +		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;
>> +		}
>>   	}
>>   
>>   	return ret;
>> -- 
>> 2.7.4
>>