Blame SOURCES/kvm-qemu-char-ignore-flow-control-if-a-PTY-s-slave-is-no.patch

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From 6a40d58e03beaef265f6c1293301f5f8860ecbea Mon Sep 17 00:00:00 2001
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From: Fam Zheng <famz@redhat.com>
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Date: Thu, 18 May 2017 09:21:22 +0200
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Subject: [PATCH 09/18] qemu-char: ignore flow control if a PTY's slave is not
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 connected
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RH-Author: Fam Zheng <famz@redhat.com>
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Message-id: <20170518092131.16571-10-famz@redhat.com>
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Patchwork-id: 75301
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O-Subject: [RHEL-7.4 qemu-kvm PATCH v3 09/18] qemu-char: ignore flow control if a PTY's slave is not connected
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Bugzilla: 1451470
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>
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From: Paolo Bonzini <pbonzini@redhat.com>
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After commit f702e62 (serial: change retry logic to avoid concurrency,
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2014-07-11), guest boot hangs if the backend is an unconnected PTY.
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The reason is that PTYs do not support G_IO_HUP, and serial_xmit is
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never called.  To fix this, simply invoke serial_xmit immediately
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(via g_idle_source_new) when this happens.
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Tested-by: Pavel Hrdina <phrdina@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit 62c339c5272ce8fbe8ca52695cee8ff40da7872e)
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 qemu-char.c | 7 +++++++
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 1 file changed, 7 insertions(+)
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diff --git a/qemu-char.c b/qemu-char.c
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index 47ac55a..08cb959 100644
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--- a/qemu-char.c
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+++ b/qemu-char.c
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@@ -1068,6 +1068,9 @@ static int pty_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
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 static GSource *pty_chr_add_watch(CharDriverState *chr, GIOCondition cond)
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 {
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     PtyCharDriver *s = chr->opaque;
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+    if (!s->connected) {
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+        return NULL;
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+    }
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     return g_io_create_watch(s->fd, cond);
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 }
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@@ -3381,6 +3384,10 @@ int qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
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     }
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     src = s->chr_add_watch(s, cond);
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+    if (!src) {
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+        return -EINVAL;
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+    }
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+
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     g_source_set_callback(src, (GSourceFunc)func, user_data, NULL);
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     tag = g_source_attach(src, NULL);
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     g_source_unref(src);
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-- 
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1.8.3.1
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