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Wed, 12 Jun 2019 06:12:02 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-148.ams2.redhat.com [10.36.116.148]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 86AF739B9; Wed, 12 Jun 2019 06:12:01 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 18FB21138648; Wed, 12 Jun 2019 08:12:00 +0200 (CEST) From: Markus Armbruster To: Kevin Wolf References: <20190611134043.9524-1-kwolf@redhat.com> <20190611134043.9524-3-kwolf@redhat.com> Date: Wed, 12 Jun 2019 08:12:00 +0200 In-Reply-To: <20190611134043.9524-3-kwolf@redhat.com> (Kevin Wolf's message of "Tue, 11 Jun 2019 15:40:34 +0200") Message-ID: <87imtbuybz.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Wed, 12 Jun 2019 06:12:02 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v2 02/11] monitor: Split monitor_init in HMP and QMP function X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: berrange@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org, dgilbert@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Kevin Wolf writes: > Instead of mixing HMP and QMP monitors in the same function, separate > the monitor creation function for both. > > Signed-off-by: Kevin Wolf > Reviewed-by: Dr. David Alan Gilbert > --- > monitor.c | 86 +++++++++++++++++++++++++++++++------------------------ > 1 file changed, 49 insertions(+), 37 deletions(-) > > diff --git a/monitor.c b/monitor.c > index 70ce9e8a77..bb23cc0450 100644 > --- a/monitor.c > +++ b/monitor.c > @@ -702,7 +702,7 @@ static void handle_hmp_command(Monitor *mon, const char *cmdline); > > static void monitor_iothread_init(void); > > -static void monitor_data_init(Monitor *mon, bool skip_flush, > +static void monitor_data_init(Monitor *mon, int flags, bool skip_flush, > bool use_io_thread) > { > if (use_io_thread && !mon_iothread) { > @@ -717,6 +717,7 @@ static void monitor_data_init(Monitor *mon, bool skip_flush, > mon->skip_flush = skip_flush; > mon->use_io_thread = use_io_thread; > mon->qmp.qmp_requests = g_queue_new(); > + mon->flags = flags; > } > > static void monitor_data_destroy(Monitor *mon) > @@ -740,7 +741,7 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index, > char *output = NULL; > Monitor *old_mon, hmp; > > - monitor_data_init(&hmp, true, false); > + monitor_data_init(&hmp, 0, true, false); > > old_mon = cur_mon; > cur_mon = &hmp; Explicit initialization replaced implicit zero-initialization. Okay. > @@ -4603,19 +4604,48 @@ static void monitor_qmp_setup_handlers_bh(void *opaque) > monitor_list_append(mon); > } > > -void monitor_init(Chardev *chr, int flags) > +static void monitor_init_qmp(Chardev *chr, int flags) > { > Monitor *mon = g_malloc(sizeof(*mon)); > - bool use_readline = flags & MONITOR_USE_READLINE; > > /* Note: we run QMP monitor in I/O thread when @chr supports that */ > - monitor_data_init(mon, false, > - (flags & MONITOR_USE_CONTROL) > - && qemu_chr_has_feature(chr, > - QEMU_CHAR_FEATURE_GCONTEXT)); > + monitor_data_init(mon, flags, false, > + qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_GCONTEXT)); > > qemu_chr_fe_init(&mon->chr, chr, &error_abort); > - mon->flags = flags; > + qemu_chr_fe_set_echo(&mon->chr, true); > + > + json_message_parser_init(&mon->qmp.parser, handle_qmp_command, mon, NULL); > + if (mon->use_io_thread) { > + /* > + * Make sure the old iowatch is gone. It's possible when > + * e.g. the chardev is in client mode, with wait=on. > + */ > + remove_fd_in_watch(chr); > + /* > + * We can't call qemu_chr_fe_set_handlers() directly here > + * since chardev might be running in the monitor I/O > + * thread. Schedule a bottom half. > + */ > + aio_bh_schedule_oneshot(iothread_get_aio_context(mon_iothread), > + monitor_qmp_setup_handlers_bh, mon); > + /* The bottom half will add @mon to @mon_list */ > + } else { > + qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, > + monitor_qmp_read, monitor_qmp_event, > + NULL, mon, NULL, true); > + monitor_list_append(mon); > + } > +} > + > +static void monitor_init_hmp(Chardev *chr, int flags) > +{ > + Monitor *mon = g_malloc(sizeof(*mon)); > + bool use_readline = flags & MONITOR_USE_READLINE; > + > + monitor_data_init(mon, flags, false, false); > + qemu_chr_fe_init(&mon->chr, chr, &error_abort); > + > if (use_readline) { > mon->rs = readline_init(monitor_readline_printf, > monitor_readline_flush, > @@ -4624,36 +4654,18 @@ void monitor_init(Chardev *chr, int flags) > monitor_read_command(mon, 0); > } > > - if (monitor_is_qmp(mon)) { > - qemu_chr_fe_set_echo(&mon->chr, true); > - json_message_parser_init(&mon->qmp.parser, handle_qmp_command, > - mon, NULL); > - if (mon->use_io_thread) { > - /* > - * Make sure the old iowatch is gone. It's possible when > - * e.g. the chardev is in client mode, with wait=on. > - */ > - remove_fd_in_watch(chr); > - /* > - * We can't call qemu_chr_fe_set_handlers() directly here > - * since chardev might be running in the monitor I/O > - * thread. Schedule a bottom half. > - */ > - aio_bh_schedule_oneshot(iothread_get_aio_context(mon_iothread), > - monitor_qmp_setup_handlers_bh, mon); > - /* The bottom half will add @mon to @mon_list */ > - return; > - } else { > - qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, > - monitor_qmp_read, monitor_qmp_event, > - NULL, mon, NULL, true); > - } > + qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, monitor_read, > + monitor_event, NULL, mon, NULL, true); > + monitor_list_append(mon); > +} > + > +void monitor_init(Chardev *chr, int flags) > +{ > + if (flags & MONITOR_USE_CONTROL) { > + monitor_init_qmp(chr, flags); > } else { > - qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, monitor_read, > - monitor_event, NULL, mon, NULL, true); > + monitor_init_hmp(chr, flags); > } > - > - monitor_list_append(mon); > } > > void monitor_cleanup(void) This part of the diff is hard to read. I'm inserting a no-op patch just for review: make two identical copies of monitor_init() called monitor_init_qmp() and monitor_init_hmp(), have monitor_init() call them depending on MONITOR_USE_CONTROL. Rebasing this patch on top of that yields a more readable git-diff -w (readable for me, YMMV): | @@ -4606,28 +4607,15 @@ static void monitor_qmp_setup_handlers_bh(void *opaque) | static void monitor_init_qmp(Chardev *chr, int flags) | { | Monitor *mon = g_malloc(sizeof(*mon)); | - bool use_readline = flags & MONITOR_USE_READLINE; See below. | | /* Note: we run QMP monitor in I/O thread when @chr supports that */ | - monitor_data_init(mon, false, | - (flags & MONITOR_USE_CONTROL) | - && qemu_chr_has_feature(chr, | - QEMU_CHAR_FEATURE_GCONTEXT)); | + monitor_data_init(mon, flags, false, | + qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_GCONTEXT)); Partially evaluated: flags & MONITOR_USE_CONTROL is true. Good. | | qemu_chr_fe_init(&mon->chr, chr, &error_abort); | - mon->flags = flags; Moved into monitor_data_init(). Good. | - if (use_readline) { | - mon->rs = readline_init(monitor_readline_printf, | - monitor_readline_flush, | - mon, | - monitor_find_completion); | - monitor_read_command(mon, 0); | - } Deleting readline support here is not a regression, because nothing ever passes MONITOR_USE_READLINE along with MONITOR_USE_CONTROL. We use only three of the four cases: * Neither flag: gdbstub.c (I have no idea why and how this uses the monitor code, and why it doesn't use readline) * Just MONITOR_USE_READLINE: - vl.c on behalf of -mon mode=readline,... and its various sugared forms - chardev/char.c for implicit mux monitor (you don't want to know) * Just MONITOR_USE_CONTROL: - vl.c on behalf of -mon mode=control,... and its various sugared forms QMP with readline could perhaps be convenient for testing. I use socat's READLINE address type myself. Speaking of odd flag combinations: MONITOR_USE_PRETTY is silently ignored unless MONITOR_USE_CONTROL. Deleting the unused (and untried) code to use QMP with readline is fine with me, but please document MONITOR_USE_READLINE is silently ignored with MONITOR_USE_CONTROL, or replace all the flags by an enumeration of the actual cases: HMP without readline, HMP with readline, QMP, pretty QMP. | - | - if (monitor_is_qmp(mon)) { | qemu_chr_fe_set_echo(&mon->chr, true); | - json_message_parser_init(&mon->qmp.parser, handle_qmp_command, | - mon, NULL); | + | + json_message_parser_init(&mon->qmp.parser, handle_qmp_command, mon, NULL); Partially evaluated: monitor_is_qmp(mon) is true. Good. Keep the line break, please. | if (mon->use_io_thread) { | /* | * Make sure the old iowatch is gone. It's possible when | @@ -4642,33 +4630,22 @@ static void monitor_init_qmp(Chardev *chr, int flags) | aio_bh_schedule_oneshot(iothread_get_aio_context(mon_iothread), | monitor_qmp_setup_handlers_bh, mon); | /* The bottom half will add @mon to @mon_list */ | - return; | } else { | qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, | monitor_qmp_read, monitor_qmp_event, | NULL, mon, NULL, true); | - } | - } else { This else belongs to if (!monitor_is_qmp(mon)). Good. | - qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, monitor_read, | - monitor_event, NULL, mon, NULL, true); | - } | - | monitor_list_append(mon); | } | +} You simplified if (mon->use_io_thread) { ... /* The bottom half will add @mon to @mon_list */ return; } else { ... } monitor_list_append(mon); to if (mon->use_io_thread) { ... /* The bottom half will add @mon to @mon_list */ } else { ... monitor_list_append(mon); } Good. | | static void monitor_init_hmp(Chardev *chr, int flags) | { | Monitor *mon = g_malloc(sizeof(*mon)); | bool use_readline = flags & MONITOR_USE_READLINE; | | - /* Note: we run QMP monitor in I/O thread when @chr supports that */ | - monitor_data_init(mon, false, | - (flags & MONITOR_USE_CONTROL) | - && qemu_chr_has_feature(chr, | - QEMU_CHAR_FEATURE_GCONTEXT)); | - | + monitor_data_init(mon, flags, false, false); Partially evaluated: flags & MONITOR_USE_CONTROL is false. Good. | qemu_chr_fe_init(&mon->chr, chr, &error_abort); | - mon->flags = flags; | + Moved into monitor_data_init(). Good. | if (use_readline) { | mon->rs = readline_init(monitor_readline_printf, | monitor_readline_flush, | @@ -4677,35 +4654,8 @@ static void monitor_init_hmp(Chardev *chr, int flags) | monitor_read_command(mon, 0); | } | | - if (monitor_is_qmp(mon)) { | - qemu_chr_fe_set_echo(&mon->chr, true); | - json_message_parser_init(&mon->qmp.parser, handle_qmp_command, | - mon, NULL); | - if (mon->use_io_thread) { | - /* | - * Make sure the old iowatch is gone. It's possible when | - * e.g. the chardev is in client mode, with wait=on. | - */ | - remove_fd_in_watch(chr); | - /* | - * We can't call qemu_chr_fe_set_handlers() directly here | - * since chardev might be running in the monitor I/O | - * thread. Schedule a bottom half. | - */ | - aio_bh_schedule_oneshot(iothread_get_aio_context(mon_iothread), | - monitor_qmp_setup_handlers_bh, mon); | - /* The bottom half will add @mon to @mon_list */ | - return; | - } else { | - qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, | - monitor_qmp_read, monitor_qmp_event, | - NULL, mon, NULL, true); | - } | - } else { | qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, monitor_read, | monitor_event, NULL, mon, NULL, true); | - } | - Partially evaluated: monitor_is_qmp(mon) is false. Good. | monitor_list_append(mon); | } | Duplicates qemu_chr_fe_init(&mon->chr, chr, &error_abort). Quite tolerable. Much clearer overall.