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From 46979f6e61d0afc31be31dab797f60c4f41c3de5 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
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Date: Fri, 20 Jul 2018 12:18:00 +0200
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Subject: [PATCH 255/268] hw/char/serial: retry write if EAGAIN
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Marc-André Lureau <marcandre.lureau@redhat.com>
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Message-id: <20180720121800.18952-3-marcandre.lureau@redhat.com>
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Patchwork-id: 81455
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O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH v2 2/2] hw/char/serial: retry write if EAGAIN
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Bugzilla: 1592817
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RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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RH-Acked-by: Markus Armbruster <armbru@redhat.com>
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RH-Acked-by: John Snow <jsnow@redhat.com>
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If the chardev returns -1 with EAGAIN errno on write(), it should try
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to send it again (EINTR is handled by the chardev itself).
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This fixes commit 019288bf137183bf3407c9824655b753bfafc99f
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"hw/char/serial: Only retry if qemu_chr_fe_write returns 0"
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Tested-by: Igor Mammedov <imammedo@redhat.com>
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Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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Message-Id: <20180716110755.12499-1-marcandre.lureau@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit f3575af130c700cea060b51a89008a76dae22259)
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Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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hw/char/serial.c | 23 ++++++++++++++---------
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1 file changed, 14 insertions(+), 9 deletions(-)
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diff --git a/hw/char/serial.c b/hw/char/serial.c
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index d4057bf..478f9a8 100644
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--- a/hw/char/serial.c
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+++ b/hw/char/serial.c
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@@ -262,15 +262,20 @@ static void serial_xmit(SerialState *s)
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if (s->mcr & UART_MCR_LOOP) {
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/* in loopback mode, say that we just received a char */
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serial_receive1(s, &s->tsr, 1);
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- } else if (qemu_chr_fe_write(&s->chr, &s->tsr, 1) == 0 &&
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- s->tsr_retry < MAX_XMIT_RETRY) {
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- assert(s->watch_tag == 0);
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- s->watch_tag =
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- qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
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- serial_watch_cb, s);
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- if (s->watch_tag > 0) {
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- s->tsr_retry++;
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- return;
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+ } else {
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+ int rc = qemu_chr_fe_write(&s->chr, &s->tsr, 1);
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+
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+ if ((rc == 0 ||
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+ (rc == -1 && errno == EAGAIN)) &&
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+ s->tsr_retry < MAX_XMIT_RETRY) {
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+ assert(s->watch_tag == 0);
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+ s->watch_tag =
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+ qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
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+ serial_watch_cb, s);
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+ if (s->watch_tag > 0) {
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+ s->tsr_retry++;
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+ return;
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+ }
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}
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}
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s->tsr_retry = 0;
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--
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1.8.3.1
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