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hw/char/serial: retry write if EAGAIN

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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 019288bf13
"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>
This commit is contained in:
Marc-André Lureau 2018-07-16 13:07:55 +02:00 committed by Paolo Bonzini
parent 0147883450
commit f3575af130
1 changed files with 14 additions and 9 deletions
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23
hw/char/serial.c
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@ -260,15 +260,20 @@ 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;