Hello Peter,
On Thu, Jan 13, 2022 at 3:48 AM Peter Xu <pet...@redhat.com> wrote:
>
> On Thu, Jan 06, 2022 at 07:13:39PM -0300, Leonardo Bras wrote:
> > @@ -558,15 +575,26 @@ static ssize_t qio_channel_socket_writev(QIOChannel
> > *ioc,
> > memcpy(CMSG_DATA(cmsg), fds, fdsize);
> > }
> >
> > + if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) {
> > + sflags = MSG_ZEROCOPY;
> > + }
> > +
> > retry:
> > - ret = sendmsg(sioc->fd, &msg, 0);
> > + ret = sendmsg(sioc->fd, &msg, sflags);
> > if (ret <= 0) {
> > - if (errno == EAGAIN) {
> > + switch (errno) {
> > + case EAGAIN:
> > return QIO_CHANNEL_ERR_BLOCK;
> > - }
> > - if (errno == EINTR) {
> > + case EINTR:
> > goto retry;
> > + case ENOBUFS:
> > + if (sflags & MSG_ZEROCOPY) {
> > + error_setg_errno(errp, errno,
> > + "Process can't lock enough memory for
> > using MSG_ZEROCOPY");
> > + return -1;
> > + }
>
> I have no idea whether it'll make a real differnece, but - should we better
> add
> a "break" here?
Here I followed the standard of the EAGAIN error, that's why I just returned -1.
IIUC A break here would cause the errp to be re-set to the default
message, after the switch.
Another option would be to add a 'default' clause, and move the
default error msg there, and return the -1
after the switch.
In the end I thought the current way was simpler, but it's no issue
to change if you think the 'default' idea would be better.
> If you agree and with that fixed, feel free to add:
>
> Reviewed-by: Peter Xu <pet...@redhat.com>
>
Thanks!
> I also wonder whether you hit ENOBUFS in any of the environments. On Fedora
> here it's by default unlimited, but just curious when we should keep an eye.
It's unlimited if you run as root IIRC.
>
> Thanks,
>
> --
> Peter Xu
>
