Re: [Qemu-devel] [PATCH 07/12] chardev: split tcp_chr_wait_connected into two methods

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Jan 15, 2019 at 11:44:37PM +0400, Marc-André Lureau wrote:
> Hi
> 
> On Tue, Jan 15, 2019 at 6:53 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
> >
> > The tcp_chr_wait_connected method can deal with either server or client
> > chardevs, but some callers only care about one of these possibilities.
> > The tcp_chr_wait_connected method will also need some refactoring to
> > reliably deal with its primary goal of allowing a device frontend to
> > wait for an established connection, which will interfere with other
> > callers.
> >
> > Split it into two methods, one responsible for server initiated
> > connections, the other responsible for client initiated connections.
> > In doing this split the tcp_char_connect_async() method is renamed
> > to become consistent with naming of the new methods.
> >
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> >  chardev/char-socket.c | 59 +++++++++++++++++++++++++++----------------
> >  1 file changed, 37 insertions(+), 22 deletions(-)
> >
> > diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> > index 3b6ff6619b..3bd1be7631 100644
> > --- a/chardev/char-socket.c
> > +++ b/chardev/char-socket.c
> > @@ -886,30 +886,47 @@ static void tcp_chr_accept(QIONetListener *listener,
> >      tcp_chr_new_client(chr, cioc);
> >  }
> >
> > -static int tcp_chr_wait_connected(Chardev *chr, Error **errp)
> > +
> > +static int tcp_chr_connect_client_sync(Chardev *chr, Error **errp)
> > +{
> > +    SocketChardev *s = SOCKET_CHARDEV(chr);
> > +    QIOChannelSocket *sioc = qio_channel_socket_new();
> > +    tcp_chr_set_client_ioc_name(chr, sioc);
> > +    if (qio_channel_socket_connect_sync(sioc, s->addr, errp) < 0) {
> > +        object_unref(OBJECT(sioc));
> > +        return -1;
> > +    }
> > +    tcp_chr_new_client(chr, sioc);
> > +    object_unref(OBJECT(sioc));
> > +    return 0;
> > +}
> > +
> > +
> > +static void tcp_chr_accept_server_sync(Chardev *chr)
> >  {
> >      SocketChardev *s = SOCKET_CHARDEV(chr);
> >      QIOChannelSocket *sioc;
> > +    info_report("QEMU waiting for connection on: %s",
> > +                chr->filename);
> > +    sioc = qio_net_listener_wait_client(s->listener);
> > +    tcp_chr_set_client_ioc_name(chr, sioc);
> > +    tcp_chr_new_client(chr, sioc);
> > +    object_unref(OBJECT(sioc));
> > +}
> > +
> >
> > +static int tcp_chr_wait_connected(Chardev *chr, Error **errp)
> > +{
> > +    SocketChardev *s = SOCKET_CHARDEV(chr);
> >      /* It can't wait on s->connected, since it is set asynchronously
> >       * in TLS and telnet cases, only wait for an accepted socket */
> >      while (!s->ioc) {
> >          if (s->is_listen) {
> > -            info_report("QEMU waiting for connection on: %s",
> > -                        chr->filename);
> > -            sioc = qio_net_listener_wait_client(s->listener);
> > -            tcp_chr_set_client_ioc_name(chr, sioc);
> > -            tcp_chr_new_client(chr, sioc);
> > -            object_unref(OBJECT(sioc));
> > +            tcp_chr_accept_server_sync(chr);
> >          } else {
> > -            sioc = qio_channel_socket_new();
> > -            tcp_chr_set_client_ioc_name(chr, sioc);
> > -            if (qio_channel_socket_connect_sync(sioc, s->addr, errp) < 0) {
> > -                object_unref(OBJECT(sioc));
> > +            if (tcp_chr_connect_client_sync(chr, errp) < 0) {
> >                  return -1;
> >              }
> > -            tcp_chr_new_client(chr, sioc);
> > -            object_unref(OBJECT(sioc));
> >          }
> >      }
> >
> > @@ -958,7 +975,7 @@ cleanup:
> >      object_unref(OBJECT(sioc));
> >  }
> >
> > -static void tcp_chr_connect_async(Chardev *chr)
> > +static void tcp_chr_connect_client_async(Chardev *chr)
> >  {
> >      SocketChardev *s = SOCKET_CHARDEV(chr);
> >      QIOChannelSocket *sioc;
> > @@ -982,7 +999,7 @@ static gboolean socket_reconnect_timeout(gpointer opaque)
> >          return false;
> >      }
> >
> > -    tcp_chr_connect_async(chr);
> > +    tcp_chr_connect_client_async(chr);
> >
> >      return false;
> >  }
> > @@ -1139,7 +1156,7 @@ static void qmp_chardev_open_socket(Chardev *chr,
> >      }
> >
> >      if (s->reconnect_time) {
> > -        tcp_chr_connect_async(chr);
> > +        tcp_chr_connect_client_async(chr);
> >      } else {
> >          if (s->is_listen) {
> >              char *name;
> > @@ -1159,17 +1176,15 @@ static void qmp_chardev_open_socket(Chardev *chr,
> >              s->addr = socket_local_address(s->listener->sioc[0]->fd, errp);
> >              update_disconnected_filename(s);
> >
> > -            if (is_waitconnect &&
> > -                qemu_chr_wait_connected(chr, errp) < 0) {
> > -                return;
> > -            }
> > -            if (!s->ioc) {
> > +            if (is_waitconnect) {
> > +                tcp_chr_accept_server_sync(chr);
> 
> Is the wait_connected() loop really unnecessary there? looks like it
> is. And there is no error path either. ok

Yes, we only need to accept a single client during normal startup.

Even the loop in tcp_chr_wait_connected is actually bogus in the
current code, but I've not removed that since later patches will
need it again.

> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> 
> > +            } else {
> >                  qio_net_listener_set_client_func_full(s->listener,
> >                                                        tcp_chr_accept,
> >                                                        chr, NULL,
> >                                                        chr->gcontext);
> >              }
> > -        } else if (qemu_chr_wait_connected(chr, errp) < 0) {
> > +        } else if (tcp_chr_connect_client_sync(chr, errp) < 0) {
> >              return;
> >          }
> >      }
> > --
> > 2.20.1
> >

Regards,
Daniel
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