From 3f81a42e218ec81f95dd388227db8b4771a472ac Mon Sep 17 00:00:00 2001 Message-Id: <3f81a42e218ec81f95dd388227db8b4771a472ac.1368111914.git.minovotn@redhat.com> In-Reply-To: <405603258af5154387bea676be1f904b6713f6ae.1368111913.git.minovotn@redhat.com> References: <405603258af5154387bea676be1f904b6713f6ae.1368111913.git.minovotn@redhat.com> From: Amit Shah Date: Wed, 24 Apr 2013 08:18:17 +0200 Subject: [PATCH 43/65] virtio-serial: make flow control explicit in virtio-console RH-Author: Amit Shah Message-id: <1e0644bbec38554bd94b21ba0c5d9b56484f9d01.1366724981.git.amit.shah@redhat.com> Patchwork-id: 50821 O-Subject: [RHEL6.5 qemu-kvm PATCH 43/65] virtio-serial: make flow control explicit in virtio-console Bugzilla: 909059 RH-Acked-by: Hans de Goede RH-Acked-by: Gerd Hoffmann RH-Acked-by: Paolo Bonzini virtio-console.c used to return a value less than the number of bytes asked to be written out to a chardev backend in case the backend is not writable. virtio-serial-bus.c then implicitly enabled flow control for that port. Make this explicit instead. Signed-off-by: Amit Shah Message-id: f5ec50b068c25422256e499cf4adc06d353bf394.1362505276.git.amit.shah@redhat.com Signed-off-by: Anthony Liguori (cherry picked from commit d6258c93a7133bb2bf2ab4e91476bc0b631ba7f1) Signed-off-by: Amit Shah Conflicts: hw/virtio-console.c hw/virtio-serial-bus.c --- hw/virtio-console.c | 19 +++++++++++-------- hw/virtio-serial-bus.c | 19 +------------------ 2 files changed, 12 insertions(+), 26 deletions(-) Signed-off-by: Michal Novotny --- hw/virtio-console.c | 19 +++++++++++-------- hw/virtio-serial-bus.c | 19 +------------------ 2 files changed, 12 insertions(+), 26 deletions(-) diff --git a/hw/virtio-console.c b/hw/virtio-console.c index 7cc4b69..06b4303 100644 --- a/hw/virtio-console.c +++ b/hw/virtio-console.c @@ -43,20 +43,23 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len) return len; } ret = qemu_chr_fe_write(vcon->chr, buf, len); - if (ret < 0 && ret != -EAGAIN) { + + if (ret <= 0) { + VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev, + vcon->port.dev.info); + /* * Ideally we'd get a better error code than just -1, but * that's what the chardev interface gives us right now. If * we had a finer-grained message, like -EPIPE, we could close - * this connection. Absent such error messages, the most we - * can do is to return 0 here. - * - * This will prevent stray -1 values to go to - * virtio-serial-bus.c and cause abort()s in - * do_flush_queued_data(). + * this connection. */ ret = 0; - qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT, chr_write_unblocked, vcon); + if (!info->is_console) { + virtio_serial_throttle_port(port, true); + qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT, chr_write_unblocked, + vcon); + } } return ret; } diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c index d598fb5..4c29373 100644 --- a/hw/virtio-serial-bus.c +++ b/hw/virtio-serial-bus.c @@ -194,24 +194,7 @@ static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq, port->elem.out_sg[i].iov_base + port->iov_offset, buf_size); - if (ret < 0 && ret != -EAGAIN) { - /* We don't handle any other type of errors here */ - abort(); - } - if (ret == -EAGAIN || (ret >= 0 && ret < buf_size)) { - /* - * this is a temporary check until chardevs can signal to - * frontends that they are writable again. This prevents - * the console from going into throttled mode (forever) - * if virtio-console is connected to a pty without a - * listener. Otherwise the guest spins forever. - * We can revert this if - * 1: chardevs can notify frondends - * 2: the guest driver does not spin in these cases - */ - if (!info->is_console) { - virtio_serial_throttle_port(port, true); - } + if (port->throttled) { port->iov_idx = i; if (ret > 0) { port->iov_offset += ret; -- 1.7.11.7