From 4b71b3a9e37d06da2ecc48e06eea7e4a4ae1cfe9 Mon Sep 17 00:00:00 2001

From: Fam Zheng <famz@redhat.com>

Date: Thu, 18 May 2017 09:21:20 +0200

Subject: [PATCH 07/18] serial: poll the serial console with G_IO_HUP

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RH-Author: Fam Zheng <famz@redhat.com>

Message-id: <20170518092131.16571-8-famz@redhat.com>

Patchwork-id: 75297

O-Subject: [RHEL-7.4 qemu-kvm PATCH v3 07/18] serial: poll the serial console with G_IO_HUP

Bugzilla: 1451470

RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>

From: Roger Pau Monne <roger.pau@citrix.com>

On FreeBSD polling a master pty while the other end is not connected

with G_IO_OUT only results in an endless wait. This is different from

the Linux behaviour, that returns immediately. In order to demonstrate

this, I have the following example code:

http://xenbits.xen.org/people/royger/test_poll.c

When executed on Linux:

$ ./test_poll

In callback

On FreeBSD instead, the callback never gets called:

$ ./test_poll

So, in order to workaround this, poll the source with G_IO_HUP (which

makes the code behave the same way on both Linux and FreeBSD).

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

Cc: Peter Crosthwaite <peter.crosthwaite@xilinx.com>

Cc: Michael Tokarev <mjt@tls.msk.ru>

Cc: "Andreas Färber" <afaerber@suse.de>

Cc: Paolo Bonzini <pbonzini@redhat.com>

Cc: xen-devel@lists.xenproject.org

[Add hw/char/cadence_uart.c too. - Paolo]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

(cherry picked from commit e02bc6de30c44fd668dc0d6e1cd1804f2eed3ed3)

Signed-off-by: Fam Zheng <famz@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

Conflicts:

	hw/char/cadence_uart.c

Downstream doesn't use qemu_chr_fe_add_watch because we don't have

38acd64b1c etc.

	monitor.c

The changed line is different because we don't have 6cff3e8594 (monitor:

protect outbuf and mux_out with mutex).

---

 hw/char/serial.c         | 2 +-

 hw/char/virtio-console.c | 3 ++-

 hw/usb/redirect.c        | 2 +-

 monitor.c                | 2 +-

 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/hw/char/serial.c b/hw/char/serial.c

index e020b0e..add4738 100644

--- a/hw/char/serial.c

+++ b/hw/char/serial.c

@@ -246,7 +246,7 @@ static gboolean serial_xmit(GIOChannel *chan, GIOCondition cond, void *opaque)

         serial_receive1(s, &s->tsr, 1);

     } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1) {

         if (s->tsr_retry >= 0 && s->tsr_retry < MAX_XMIT_RETRY &&

-            qemu_chr_fe_add_watch(s->chr, G_IO_OUT, serial_xmit, s) > 0) {

+            qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP, serial_xmit, s) > 0) {

             s->tsr_retry++;

             return FALSE;

         }

diff --git a/hw/char/virtio-console.c b/hw/char/virtio-console.c

index 1b01dcd..69dd95a 100644

--- a/hw/char/virtio-console.c

+++ b/hw/char/virtio-console.c

@@ -66,7 +66,8 @@ static ssize_t flush_buf(VirtIOSerialPort *port,

         if (!k->is_console) {

             virtio_serial_throttle_port(port, true);

             if (!vcon->watch) {

-                vcon->watch = qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT,

+                vcon->watch = qemu_chr_fe_add_watch(vcon->chr,

+                                                    G_IO_OUT|G_IO_HUP,

                                                     chr_write_unblocked, vcon);

             }

         }

diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c

index e3b9f32..3fe2106 100644

--- a/hw/usb/redirect.c

+++ b/hw/usb/redirect.c

@@ -284,7 +284,7 @@ static int usbredir_write(void *priv, uint8_t *data, int count)

     r = qemu_chr_fe_write(dev->cs, data, count);

     if (r < count) {

         if (!dev->watch) {

-            dev->watch = qemu_chr_fe_add_watch(dev->cs, G_IO_OUT,

+            dev->watch = qemu_chr_fe_add_watch(dev->cs, G_IO_OUT|G_IO_HUP,

                                                usbredir_write_unblocked, dev);

         }

         if (r < 0) {

diff --git a/monitor.c b/monitor.c

index 1b28ff3..393a508 100644

--- a/monitor.c

+++ b/monitor.c

@@ -300,7 +300,7 @@ void monitor_flush(Monitor *mon)

             mon->outbuf = tmp;

         }

         if (mon->watch == 0) {

-            mon->watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,

+            mon->watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT|G_IO_HUP,

                                                monitor_unblocked, mon);

         }

     }

-- 

1.8.3.1