qemu-kvm/SOURCES/kvm-hw-char-serial-retry-write-if-EAGAIN.patch

73 lines
2.8 KiB
Diff

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