From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 94D35CAC592 for ; Fri, 19 Sep 2025 13:31:22 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uzbBL-0002XN-RV; Fri, 19 Sep 2025 09:29:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uzbBJ-0002WP-5U for qemu-devel@nongnu.org; Fri, 19 Sep 2025 09:29:45 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uzbBA-0001vN-Nx for qemu-devel@nongnu.org; Fri, 19 Sep 2025 09:29:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1758288570; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qm12Bt1q93b+aYnp6CWK0gI7z8+VHd0QjAvjlijmfb0=; b=glSDzrV9istqJ/Tc3IAIofFCu4iKS2YLzm4DR0q3VEOIB8NgUWX9jeY0jo6DsQJEv0elfB 9+WQBZE0jdeoP5gv2yzAt4dx/1KDoQ3rRdS33YBa87B5qAn4I0XyVN2iIquxU4Fgr8Xra7 S0ce6rlaeGfimESDi5sAmknVTOP0sws= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-41-oeKRizvZNFmtRsk1QWVLGg-1; Fri, 19 Sep 2025 09:29:25 -0400 X-MC-Unique: oeKRizvZNFmtRsk1QWVLGg-1 X-Mimecast-MFC-AGG-ID: oeKRizvZNFmtRsk1QWVLGg_1758288564 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EAFFA195608B; Fri, 19 Sep 2025 13:29:23 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.187]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CD2361956045; Fri, 19 Sep 2025 13:29:18 +0000 (UTC) Date: Fri, 19 Sep 2025 14:29:15 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Hanna Reitz , Kevin Wolf , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Christian Schoenebeck , Richard Henderson , Manos Pitsidianakis , Stefan Weil , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Gerd Hoffmann , Paolo Bonzini , "Dr. David Alan Gilbert" Subject: Re: [PATCH v3 12/20] monitor: introduce monitor_cur_hmp() function Message-ID: References: <20250910180357.320297-1-berrange@redhat.com> <20250910180357.320297-13-berrange@redhat.com> <87zfaqwr2a.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87zfaqwr2a.fsf@pond.sub.org> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.105, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Sep 19, 2025 at 02:43:41PM +0200, Markus Armbruster wrote: > Daniel P. Berrangé writes: > > > A number of callers use monitor_cur() followed by !monitor_cur_is_qmp(). > > "A number of"? I can see just one: > > int error_vprintf(const char *fmt, va_list ap) > { > Monitor *cur_mon = monitor_cur(); > > if (cur_mon && !monitor_cur_is_qmp()) { > return monitor_vprintf(cur_mon, fmt, ap); > } > return vfprintf(stderr, fmt, ap); > } Opps, that'll be referring to the other use of monitor_cur() in my patches that I then removed when I re-ordered the series. > > > This is undesirable because monitor_cur_is_qmp() will itself call > > monitor_cur() again, and monitor_cur() must acquire locks and do > > hash table lookups. Introducing a monitor_cur_hmp() helper will > > combine the two operations into one reducing cost. > > This made me expect the patch replaces the undesirable uses. It does > not; the new function remains unused for now. > > > Signed-off-by: Daniel P. Berrangé > > --- > > include/monitor/monitor.h | 1 + > > monitor/monitor.c | 14 ++++++++++++++ > > stubs/monitor-core.c | 5 +++++ > > tests/unit/test-util-sockets.c | 1 + > > 4 files changed, 21 insertions(+) > > > > diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h > > index 296690e1f1..c3b79b960a 100644 > > --- a/include/monitor/monitor.h > > +++ b/include/monitor/monitor.h > > @@ -14,6 +14,7 @@ typedef struct MonitorOptions MonitorOptions; > > extern QemuOptsList qemu_mon_opts; > > > > Monitor *monitor_cur(void); > > +Monitor *monitor_cur_hmp(void); > > Monitor *monitor_set_cur(Coroutine *co, Monitor *mon); > > bool monitor_cur_is_qmp(void); > > > > diff --git a/monitor/monitor.c b/monitor/monitor.c > > index e1e5dbfcbe..cff502c53e 100644 > > --- a/monitor/monitor.c > > +++ b/monitor/monitor.c > > @@ -84,6 +84,20 @@ Monitor *monitor_cur(void) > > return mon; > > } > > > > +Monitor *monitor_cur_hmp(void) > > +{ > > + Monitor *mon; > > + > > + qemu_mutex_lock(&monitor_lock); > > + mon = g_hash_table_lookup(coroutine_mon, qemu_coroutine_self()); > > + if (mon && monitor_is_qmp(mon)) { > > + mon = NULL; > > + } > > + qemu_mutex_unlock(&monitor_lock); > > + > > + return mon; > > +} > > + > > /** > > * Sets a new current monitor and returns the old one. > > * > > diff --git a/stubs/monitor-core.c b/stubs/monitor-core.c > > index b498a0f1af..1e0b11ec29 100644 > > --- a/stubs/monitor-core.c > > +++ b/stubs/monitor-core.c > > @@ -7,6 +7,11 @@ Monitor *monitor_cur(void) > > return NULL; > > } > > > > +Monitor *monitor_cur_hmp(void) > > +{ > > + return NULL; > > +} > > + > > bool monitor_cur_is_qmp(void) > > { > > return false; > > diff --git a/tests/unit/test-util-sockets.c b/tests/unit/test-util-sockets.c > > index bd48731ea2..d40813c682 100644 > > --- a/tests/unit/test-util-sockets.c > > +++ b/tests/unit/test-util-sockets.c > > @@ -72,6 +72,7 @@ int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp) > > * otherwise we get duplicate syms at link time. > > */ > > Monitor *monitor_cur(void) { return cur_mon; } > > +Monitor *monitor_cur_hmp(void) { return cur_mon; } > > @cur_mon is a fake here. Why do you make this fake monitor HMP? If we > somehow call error_vprintf(), it'll call monitor_vprintf(), which will > dereference the fake monitor. Best possible outcome would be an > immediate crash. Current code has 'monitor_cur' return 'cur_mon', and 'monitor_cur_is_qmp' (below) return 'false'. IOW, the current behaviour of the stubs is that 'cur_mon' is HMP, so I just maintained those semantics. We've stubbed monitor_vprintf() too so it'll abort() no matter what, as we don't expect that code path to be triggered from this test suite. > > bool monitor_cur_is_qmp(void) { return false; } > > Monitor *monitor_set_cur(Coroutine *co, Monitor *mon) { abort(); } > > int monitor_vprintf(Monitor *mon, const char *fmt, va_list ap) { abort(); } With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|