Re: [dpdk-dev] [PATCH 1/3] vhost: do not generate signal when sendmsg fails

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 03/29/2018 03:25 PM, Tiwei Bie wrote:
> On Thu, Mar 29, 2018 at 02:19:35PM +0200, Maxime Coquelin wrote:
>> Hi Tiwei,
>>
>> On 03/06/2018 11:43 AM, Tiwei Bie wrote:
>>> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
>>
>> Could you please elaborate a bit more why this is needed?
>> Is it fixing a real issue or just an improvement?
> 
> My bad, I really should write a more useful commit log..
> 
> I saw your comments on this mail:
> 
> http://dpdk.org/ml/archives/dev/2018-March/094201.html
> 
> Thank you so much! :-)
> 
> It's fixing an issue I met when adding the vDPA support.
> SIGPIPE would be generated when sending messages via a
> closed slave fd, and it will terminate the process by
> default. But as a library, we shouldn't crash the process
> in this case, instead we just need to return with an error.
> I didn't meet this issue without my vDPA related changes,
> so I didn't put a fixline on it. That is to say, I'm
> treating it as an improvement.

Great, thanks for the details!
I'll apply the patch with below commit message.

Maxime
> 
> Below is the commit log for your reference:
> 
> ------ START HERE ------
> 
> vhost: do not generate signal when sendmsg fails
> 
> More precisely, do not generate a SIGPIPE signal if the peer
> has closed the connection. Otherwise, it will terminate the
> process by default. As a library, we should avoid terminating
> the application process when error happens and just need to
> return with an error.
> 
> ------ END HERE ------
> 
> Thanks again! :-)
> 
> Best regards,
> Tiwei Bie
> 
>>
>> Thanks!
>> Maxime
>>> ---
>>>    lib/librte_vhost/socket.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
>>> index 0354740fa..d703d2114 100644
>>> --- a/lib/librte_vhost/socket.c
>>> +++ b/lib/librte_vhost/socket.c
>>> @@ -181,7 +181,7 @@ send_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num)
>>>    	}
>>>    	do {
>>> -		ret = sendmsg(sockfd, &msgh, 0);
>>> +		ret = sendmsg(sockfd, &msgh, MSG_NOSIGNAL);
>>>    	} while (ret < 0 && errno == EINTR);
>>>    	if (ret < 0) {
>>>