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

[Tiwei Bie <tiwei.bie@intel.com>]

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.

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) {
> >