From patchwork Fri Oct 12 07:52:49 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 191068 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 0834F2C0093 for ; Fri, 12 Oct 2012 18:53:20 +1100 (EST) Received: from localhost ([::1]:54159 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TMa3Z-0005bK-A6 for incoming@patchwork.ozlabs.org; Fri, 12 Oct 2012 03:53:17 -0400 Received: from eggs.gnu.org ([208.118.235.92]:46511) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TMa3N-0005aB-Cu for qemu-devel@nongnu.org; Fri, 12 Oct 2012 03:53:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TMa3K-0002pP-Jl for qemu-devel@nongnu.org; Fri, 12 Oct 2012 03:53:05 -0400 Received: from goliath.siemens.de ([192.35.17.28]:29646) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TMa3K-0002p5-9x for qemu-devel@nongnu.org; Fri, 12 Oct 2012 03:53:02 -0400 Received: from mail1.siemens.de (localhost [127.0.0.1]) by goliath.siemens.de (8.13.6/8.13.6) with ESMTP id q9C7qoMc029962; Fri, 12 Oct 2012 09:52:50 +0200 Received: from mchn199C.mchp.siemens.de ([139.22.128.147]) by mail1.siemens.de (8.13.6/8.13.6) with SMTP id q9C7qosO029501; Fri, 12 Oct 2012 09:52:50 +0200 Message-ID: <5077CC51.4080200@siemens.com> Date: Fri, 12 Oct 2012 09:52:49 +0200 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: qemu-devel , Anthony Liguori References: <5073083C.1060201@siemens.com> In-Reply-To: <5073083C.1060201@siemens.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 192.35.17.28 Cc: Peter Maydell , Aurelien Jarno , Paolo Bonzini Subject: [Qemu-devel] [PATCH v2] chardev: Use timer instead of bottom-half to postpone open event X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org As the block layer may decide to flush bottom-halfs while the machine is still initializing (e.g. to read geometry data from the disk), our postponed open event may be processed before the last frontend registered with a muxed chardev. Until the semantics of BHs have been clarified, use an expired timer to achieve the same effect (suggested by Paolo Bonzini). This requires to perform the alarm timer initialization earlier as otherwise timer subsystem can be used before being ready. Signed-off-by: Jan Kiszka --- Changes in v2: - Move init_alarm_timer call to fix e.g. -monitor stdio qemu-char.c | 13 +++++++------ qemu-char.h | 2 +- vl.c | 10 +++++----- 3 files changed, 13 insertions(+), 12 deletions(-) diff --git a/qemu-char.c b/qemu-char.c index b082bae..d8eed21 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -123,19 +123,20 @@ void qemu_chr_be_event(CharDriverState *s, int event) s->chr_event(s->handler_opaque, event); } -static void qemu_chr_generic_open_bh(void *opaque) +static void qemu_chr_fire_open_event(void *opaque) { CharDriverState *s = opaque; qemu_chr_be_event(s, CHR_EVENT_OPENED); - qemu_bh_delete(s->bh); - s->bh = NULL; + qemu_free_timer(s->open_timer); + s->open_timer = NULL; } void qemu_chr_generic_open(CharDriverState *s) { - if (s->bh == NULL) { - s->bh = qemu_bh_new(qemu_chr_generic_open_bh, s); - qemu_bh_schedule(s->bh); + if (s->open_timer == NULL) { + s->open_timer = qemu_new_timer_ms(vm_clock, + qemu_chr_fire_open_event, s); + qemu_mod_timer(s->open_timer, qemu_get_clock_ms(vm_clock) - 1); } } diff --git a/qemu-char.h b/qemu-char.h index 486644b..297dd98 100644 --- a/qemu-char.h +++ b/qemu-char.h @@ -69,7 +69,7 @@ struct CharDriverState { void (*chr_guest_open)(struct CharDriverState *chr); void (*chr_guest_close)(struct CharDriverState *chr); void *opaque; - QEMUBH *bh; + QEMUTimer *open_timer; char *label; char *filename; int opened; diff --git a/vl.c b/vl.c index 5b357a3..586773c 100644 --- a/vl.c +++ b/vl.c @@ -3439,6 +3439,11 @@ int main(int argc, char **argv, char **envp) add_device_config(DEV_VIRTCON, "vc:80Cx24C"); } + if (init_timer_alarm() < 0) { + fprintf(stderr, "could not initialize alarm timer\n"); + exit(1); + } + socket_init(); if (qemu_opts_foreach(qemu_find_opts("chardev"), chardev_init_func, NULL, 1) != 0) @@ -3506,11 +3511,6 @@ int main(int argc, char **argv, char **envp) os_set_line_buffering(); - if (init_timer_alarm() < 0) { - fprintf(stderr, "could not initialize alarm timer\n"); - exit(1); - } - #ifdef CONFIG_SPICE /* spice needs the timers to be initialized by this point */ qemu_spice_init();