From nobody Sun Feb 8 10:31:40 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1526641773642178.13332805732819; Fri, 18 May 2018 04:09:33 -0700 (PDT) Received: from localhost ([::1]:38053 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fJdGJ-00083X-AD for importer@patchew.org; Fri, 18 May 2018 07:09:27 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59911) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fJdEA-0006Qb-C7 for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fJdE9-0005aa-77 for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:14 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:42944 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fJdE9-0005aR-1b for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:13 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B0FFD81FE159 for ; Fri, 18 May 2018 11:07:12 +0000 (UTC) Received: from xz-mi.nay.redhat.com (dhcp-14-151.nay.redhat.com [10.66.14.151]) by smtp.corp.redhat.com (Postfix) with ESMTP id 12576202358C; Fri, 18 May 2018 11:07:09 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Fri, 18 May 2018 19:07:01 +0800 Message-Id: <20180518110704.10849-2-peterx@redhat.com> In-Reply-To: <20180518110704.10849-1-peterx@redhat.com> References: <20180518110704.10849-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 18 May 2018 11:07:12 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 18 May 2018 11:07:12 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'peterx@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v6 1/4] monitor: rename out_lock to mon_lock X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Markus Armbruster , peterx@redhat.com, "Dr . David Alan Gilbert" , Stefan Hajnoczi , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The out_lock is protecting a few Monitor fields. In the future the monitor code will start to run in multiple threads. We are going to turn it into a bigger lock to protect not only the out buffer but also all the rest. Since at it, rearrange the Monitor struct a bit. Reviewed-by: Stefan Hajnoczi Signed-off-by: Peter Xu --- monitor.c | 53 +++++++++++++++++++++++++++++------------------------ 1 file changed, 29 insertions(+), 24 deletions(-) diff --git a/monitor.c b/monitor.c index 46814af533..14c681dc8a 100644 --- a/monitor.c +++ b/monitor.c @@ -207,15 +207,6 @@ struct Monitor { int suspend_cnt; /* Needs to be accessed atomically */ bool skip_flush; bool use_io_thr; - - /* We can't access guest memory when holding the lock */ - QemuMutex out_lock; - QString *outbuf; - guint out_watch; - - /* Read under either BQL or out_lock, written with BQL+out_lock. */ - int mux_out; - ReadLineState *rs; MonitorQMP qmp; gchar *mon_cpu_path; @@ -224,6 +215,20 @@ struct Monitor { mon_cmd_t *cmd_table; QLIST_HEAD(,mon_fd_t) fds; QTAILQ_ENTRY(Monitor) entry; + + /* + * The per-monitor lock. We can't access guest memory when holding + * the lock. + */ + QemuMutex mon_lock; + + /* + * Fields that are protected by the per-monitor lock. + */ + QString *outbuf; + guint out_watch; + /* Read under either BQL or mon_lock, written with BQL+mon_lock. */ + int mux_out; }; =20 /* Let's add monitor global variables to this struct. */ @@ -366,14 +371,14 @@ static gboolean monitor_unblocked(GIOChannel *chan, G= IOCondition cond, { Monitor *mon =3D opaque; =20 - qemu_mutex_lock(&mon->out_lock); + qemu_mutex_lock(&mon->mon_lock); mon->out_watch =3D 0; monitor_flush_locked(mon); - qemu_mutex_unlock(&mon->out_lock); + qemu_mutex_unlock(&mon->mon_lock); return FALSE; } =20 -/* Called with mon->out_lock held. */ +/* Called with mon->mon_lock held. */ static void monitor_flush_locked(Monitor *mon) { int rc; @@ -411,9 +416,9 @@ static void monitor_flush_locked(Monitor *mon) =20 void monitor_flush(Monitor *mon) { - qemu_mutex_lock(&mon->out_lock); + qemu_mutex_lock(&mon->mon_lock); monitor_flush_locked(mon); - qemu_mutex_unlock(&mon->out_lock); + qemu_mutex_unlock(&mon->mon_lock); } =20 /* flush at every end of line */ @@ -421,7 +426,7 @@ static void monitor_puts(Monitor *mon, const char *str) { char c; =20 - qemu_mutex_lock(&mon->out_lock); + qemu_mutex_lock(&mon->mon_lock); for(;;) { c =3D *str++; if (c =3D=3D '\0') @@ -434,7 +439,7 @@ static void monitor_puts(Monitor *mon, const char *str) monitor_flush_locked(mon); } } - qemu_mutex_unlock(&mon->out_lock); + qemu_mutex_unlock(&mon->mon_lock); } =20 void monitor_vprintf(Monitor *mon, const char *fmt, va_list ap) @@ -725,7 +730,7 @@ static void monitor_data_init(Monitor *mon, bool skip_f= lush, bool use_io_thr) { memset(mon, 0, sizeof(Monitor)); - qemu_mutex_init(&mon->out_lock); + qemu_mutex_init(&mon->mon_lock); qemu_mutex_init(&mon->qmp.qmp_queue_lock); mon->outbuf =3D qstring_new(); /* Use *mon_cmds by default. */ @@ -745,7 +750,7 @@ static void monitor_data_destroy(Monitor *mon) } readline_free(mon->rs); qobject_unref(mon->outbuf); - qemu_mutex_destroy(&mon->out_lock); + qemu_mutex_destroy(&mon->mon_lock); qemu_mutex_destroy(&mon->qmp.qmp_queue_lock); monitor_qmp_cleanup_req_queue_locked(mon); monitor_qmp_cleanup_resp_queue_locked(mon); @@ -777,13 +782,13 @@ char *qmp_human_monitor_command(const char *command_l= ine, bool has_cpu_index, handle_hmp_command(&hmp, command_line); cur_mon =3D old_mon; =20 - qemu_mutex_lock(&hmp.out_lock); + qemu_mutex_lock(&hmp.mon_lock); if (qstring_get_length(hmp.outbuf) > 0) { output =3D g_strdup(qstring_get_str(hmp.outbuf)); } else { output =3D g_strdup(""); } - qemu_mutex_unlock(&hmp.out_lock); + qemu_mutex_unlock(&hmp.mon_lock); =20 out: monitor_data_destroy(&hmp); @@ -4377,9 +4382,9 @@ static void monitor_event(void *opaque, int event) =20 switch (event) { case CHR_EVENT_MUX_IN: - qemu_mutex_lock(&mon->out_lock); + qemu_mutex_lock(&mon->mon_lock); mon->mux_out =3D 0; - qemu_mutex_unlock(&mon->out_lock); + qemu_mutex_unlock(&mon->mon_lock); if (mon->reset_seen) { readline_restart(mon->rs); monitor_resume(mon); @@ -4399,9 +4404,9 @@ static void monitor_event(void *opaque, int event) } else { atomic_inc(&mon->suspend_cnt); } - qemu_mutex_lock(&mon->out_lock); + qemu_mutex_lock(&mon->mon_lock); mon->mux_out =3D 1; - qemu_mutex_unlock(&mon->out_lock); + qemu_mutex_unlock(&mon->mon_lock); break; =20 case CHR_EVENT_OPENED: --=20 2.17.0 From nobody Sun Feb 8 10:31:40 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1526641904535200.8940271508004; Fri, 18 May 2018 04:11:44 -0700 (PDT) Received: from localhost ([::1]:38072 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fJdIV-0002C1-Mt for importer@patchew.org; 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Fri, 18 May 2018 11:07:13 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Fri, 18 May 2018 19:07:02 +0800 Message-Id: <20180518110704.10849-3-peterx@redhat.com> In-Reply-To: <20180518110704.10849-1-peterx@redhat.com> References: <20180518110704.10849-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 18 May 2018 11:07:15 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 18 May 2018 11:07:15 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'peterx@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v6 2/4] monitor: protect mon->fds with mon_lock X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Markus Armbruster , peterx@redhat.com, "Dr . David Alan Gilbert" , Stefan Hajnoczi , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" mon->fds were protected by BQL. Now protect it by mon_lock so that it can even be used in monitor iothread. Reviewed-by: Stefan Hajnoczi Reviewed-by: Markus Armbruster Signed-off-by: Peter Xu --- monitor.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/monitor.c b/monitor.c index 14c681dc8a..d6c3c08932 100644 --- a/monitor.c +++ b/monitor.c @@ -213,7 +213,6 @@ struct Monitor { BlockCompletionFunc *password_completion_cb; void *password_opaque; mon_cmd_t *cmd_table; - QLIST_HEAD(,mon_fd_t) fds; QTAILQ_ENTRY(Monitor) entry; =20 /* @@ -225,6 +224,7 @@ struct Monitor { /* * Fields that are protected by the per-monitor lock. */ + QLIST_HEAD(, mon_fd_t) fds; QString *outbuf; guint out_watch; /* Read under either BQL or mon_lock, written with BQL+mon_lock. */ @@ -2189,7 +2189,7 @@ static void hmp_acl_remove(Monitor *mon, const QDict = *qdict) void qmp_getfd(const char *fdname, Error **errp) { mon_fd_t *monfd; - int fd; + int fd, tmp_fd; =20 fd =3D qemu_chr_fe_get_msgfd(&cur_mon->chr); if (fd =3D=3D -1) { @@ -2204,13 +2204,17 @@ void qmp_getfd(const char *fdname, Error **errp) return; } =20 + qemu_mutex_lock(&cur_mon->mon_lock); QLIST_FOREACH(monfd, &cur_mon->fds, next) { if (strcmp(monfd->name, fdname) !=3D 0) { continue; } =20 - close(monfd->fd); + tmp_fd =3D monfd->fd; monfd->fd =3D fd; + qemu_mutex_unlock(&cur_mon->mon_lock); + /* Make sure close() is out of critical section */ + close(tmp_fd); return; } =20 @@ -2219,24 +2223,31 @@ void qmp_getfd(const char *fdname, Error **errp) monfd->fd =3D fd; =20 QLIST_INSERT_HEAD(&cur_mon->fds, monfd, next); + qemu_mutex_unlock(&cur_mon->mon_lock); } =20 void qmp_closefd(const char *fdname, Error **errp) { mon_fd_t *monfd; + int tmp_fd; =20 + qemu_mutex_lock(&cur_mon->mon_lock); QLIST_FOREACH(monfd, &cur_mon->fds, next) { if (strcmp(monfd->name, fdname) !=3D 0) { continue; } =20 QLIST_REMOVE(monfd, next); - close(monfd->fd); + tmp_fd =3D monfd->fd; g_free(monfd->name); g_free(monfd); + qemu_mutex_unlock(&cur_mon->mon_lock); + /* Make sure close() is out of critical section */ + close(tmp_fd); return; } =20 + qemu_mutex_unlock(&cur_mon->mon_lock); error_setg(errp, QERR_FD_NOT_FOUND, fdname); } =20 @@ -2244,6 +2255,7 @@ int monitor_get_fd(Monitor *mon, const char *fdname, = Error **errp) { mon_fd_t *monfd; =20 + qemu_mutex_lock(&mon->mon_lock); QLIST_FOREACH(monfd, &mon->fds, next) { int fd; =20 @@ -2257,10 +2269,12 @@ int monitor_get_fd(Monitor *mon, const char *fdname= , Error **errp) QLIST_REMOVE(monfd, next); g_free(monfd->name); g_free(monfd); + qemu_mutex_unlock(&mon->mon_lock); =20 return fd; } =20 + qemu_mutex_unlock(&mon->mon_lock); error_setg(errp, "File descriptor named '%s' has not been found", fdna= me); return -1; } --=20 2.17.0 From nobody Sun Feb 8 10:31:40 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1526641776690722.4137681689217; Fri, 18 May 2018 04:09:36 -0700 (PDT) Received: from localhost ([::1]:38054 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fJdGQ-00087V-Pv for importer@patchew.org; Fri, 18 May 2018 07:09:34 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59956) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fJdEI-0006Tt-PD for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fJdEF-0005eV-Ix for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:22 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:42948 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fJdEF-0005eM-FK for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:19 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 264DC81FE159 for ; Fri, 18 May 2018 11:07:19 +0000 (UTC) Received: from xz-mi.nay.redhat.com (dhcp-14-151.nay.redhat.com [10.66.14.151]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7C2022026DFD; Fri, 18 May 2018 11:07:16 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Fri, 18 May 2018 19:07:03 +0800 Message-Id: <20180518110704.10849-4-peterx@redhat.com> In-Reply-To: <20180518110704.10849-1-peterx@redhat.com> References: <20180518110704.10849-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 18 May 2018 11:07:19 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 18 May 2018 11:07:19 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'peterx@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v6 3/4] monitor: more comments on lock-free fleids/funcs X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Markus Armbruster , peterx@redhat.com, "Dr . David Alan Gilbert" , Stefan Hajnoczi , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Add some explicit comment for both Readline and cpu_set/cpu_get helpers that they do not need the mon_lock protection. Signed-off-by: Peter Xu --- monitor.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/monitor.c b/monitor.c index d6c3c08932..696109acb4 100644 --- a/monitor.c +++ b/monitor.c @@ -207,7 +207,14 @@ struct Monitor { int suspend_cnt; /* Needs to be accessed atomically */ bool skip_flush; bool use_io_thr; + + /* + * ReadLineState is only used in parser, and the parser of a + * monitor will only be run either in main thread or monitor + * IOThread but never both, so no lock is needed when accessing. + */ ReadLineState *rs; + MonitorQMP qmp; gchar *mon_cpu_path; BlockCompletionFunc *password_completion_cb; @@ -1313,7 +1320,7 @@ void qmp_qmp_capabilities(bool has_enable, QMPCapabil= ityList *enable, cur_mon->qmp.commands =3D &qmp_commands; } =20 -/* set the current CPU defined by the user */ +/* Set the current CPU defined by the user. Callers must hold BQL. */ int monitor_set_cpu(int cpu_index) { CPUState *cpu; @@ -1327,6 +1334,7 @@ int monitor_set_cpu(int cpu_index) return 0; } =20 +/* Callers must hold BQL. */ static CPUState *mon_get_cpu_sync(bool synchronize) { CPUState *cpu; --=20 2.17.0 From nobody Sun Feb 8 10:31:40 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1526641779579150.81236912819736; Fri, 18 May 2018 04:09:39 -0700 (PDT) Received: from localhost ([::1]:38055 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fJdGU-0008A7-Oe for importer@patchew.org; Fri, 18 May 2018 07:09:38 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59968) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fJdEK-0006Vx-4C for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fJdEI-0005gB-T2 for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:24 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:42954 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fJdEI-0005fx-Ne for qemu-devel@nongnu.org; Fri, 18 May 2018 07:07:22 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5AF9581FE159 for ; Fri, 18 May 2018 11:07:22 +0000 (UTC) Received: from xz-mi.nay.redhat.com (dhcp-14-151.nay.redhat.com [10.66.14.151]) by smtp.corp.redhat.com (Postfix) with ESMTP id B0BDA2024CBC; Fri, 18 May 2018 11:07:19 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Fri, 18 May 2018 19:07:04 +0800 Message-Id: <20180518110704.10849-5-peterx@redhat.com> In-Reply-To: <20180518110704.10849-1-peterx@redhat.com> References: <20180518110704.10849-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 18 May 2018 11:07:22 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 18 May 2018 11:07:22 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'peterx@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v6 4/4] monitor: add lock to protect mon_fdsets X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Markus Armbruster , peterx@redhat.com, "Dr . David Alan Gilbert" , Stefan Hajnoczi , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Similar to previous patch, but introduce a new global big lock for mon_fdsets. Take it where needed. The monitor_fdset_get_fd() handling is a bit tricky: now we need to call qemu_mutex_unlock() which might pollute errno, so we need to make sure the correct errno be passed up to the callers. Signed-off-by: Peter Xu --- monitor.c | 79 +++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 65 insertions(+), 14 deletions(-) diff --git a/monitor.c b/monitor.c index 696109acb4..84064a0b89 100644 --- a/monitor.c +++ b/monitor.c @@ -269,6 +269,9 @@ typedef struct QMPRequest QMPRequest; /* Protects mon_list, monitor_event_state. */ static QemuMutex monitor_lock; =20 +/* Protects mon_fdsets */ +static QemuMutex mon_fdsets_lock; + static QTAILQ_HEAD(mon_list, Monitor) mon_list; static QLIST_HEAD(mon_fdsets, MonFdset) mon_fdsets; static int mon_refcount; @@ -285,6 +288,16 @@ static QEMUClockType event_clock_type =3D QEMU_CLOCK_R= EALTIME; static void monitor_command_cb(void *opaque, const char *cmdline, void *readline_opaque); =20 +/* + * This lock can be used very early, even during param parsing. + * Meanwhile it can also be used even at the end of main. Let's keep + * it initialized for the whole lifecycle of QEMU. + */ +static void __attribute__((constructor)) mon_fdsets_lock_init(void) +{ + qemu_mutex_init(&mon_fdsets_lock); +} + /** * Is @mon a QMP monitor? */ @@ -2314,9 +2327,11 @@ static void monitor_fdsets_cleanup(void) MonFdset *mon_fdset; MonFdset *mon_fdset_next; =20 + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH_SAFE(mon_fdset, &mon_fdsets, next, mon_fdset_next) { monitor_fdset_cleanup(mon_fdset); } + qemu_mutex_unlock(&mon_fdsets_lock); } =20 AddfdInfo *qmp_add_fd(bool has_fdset_id, int64_t fdset_id, bool has_opaque, @@ -2351,6 +2366,7 @@ void qmp_remove_fd(int64_t fdset_id, bool has_fd, int= 64_t fd, Error **errp) MonFdsetFd *mon_fdset_fd; char fd_str[60]; =20 + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { if (mon_fdset->id !=3D fdset_id) { continue; @@ -2370,10 +2386,12 @@ void qmp_remove_fd(int64_t fdset_id, bool has_fd, i= nt64_t fd, Error **errp) goto error; } monitor_fdset_cleanup(mon_fdset); + qemu_mutex_unlock(&mon_fdsets_lock); return; } =20 error: + qemu_mutex_unlock(&mon_fdsets_lock); if (has_fd) { snprintf(fd_str, sizeof(fd_str), "fdset-id:%" PRId64 ", fd:%" PRId= 64, fdset_id, fd); @@ -2389,6 +2407,7 @@ FdsetInfoList *qmp_query_fdsets(Error **errp) MonFdsetFd *mon_fdset_fd; FdsetInfoList *fdset_list =3D NULL; =20 + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { FdsetInfoList *fdset_info =3D g_malloc0(sizeof(*fdset_info)); FdsetFdInfoList *fdsetfd_list =3D NULL; @@ -2418,6 +2437,7 @@ FdsetInfoList *qmp_query_fdsets(Error **errp) fdset_info->next =3D fdset_list; fdset_list =3D fdset_info; } + qemu_mutex_unlock(&mon_fdsets_lock); =20 return fdset_list; } @@ -2430,6 +2450,7 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdse= t_id, int64_t fdset_id, MonFdsetFd *mon_fdset_fd; AddfdInfo *fdinfo; =20 + qemu_mutex_lock(&mon_fdsets_lock); if (has_fdset_id) { QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { /* Break if match found or match impossible due to ordering by= ID */ @@ -2450,6 +2471,7 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdse= t_id, int64_t fdset_id, if (fdset_id < 0) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "fdset-id", "a non-negative value"); + qemu_mutex_unlock(&mon_fdsets_lock); return NULL; } /* Use specified fdset ID */ @@ -2500,16 +2522,22 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fd= set_id, int64_t fdset_id, fdinfo->fdset_id =3D mon_fdset->id; fdinfo->fd =3D mon_fdset_fd->fd; =20 + qemu_mutex_unlock(&mon_fdsets_lock); return fdinfo; } =20 int monitor_fdset_get_fd(int64_t fdset_id, int flags) { -#ifndef _WIN32 +#ifdef _WIN32 + errno =3D ENOENT; + return -1; +#else MonFdset *mon_fdset; MonFdsetFd *mon_fdset_fd; int mon_fd_flags; + int ret =3D -ENOENT; =20 + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { if (mon_fdset->id !=3D fdset_id) { continue; @@ -2517,49 +2545,68 @@ int monitor_fdset_get_fd(int64_t fdset_id, int flag= s) QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) { mon_fd_flags =3D fcntl(mon_fdset_fd->fd, F_GETFL); if (mon_fd_flags =3D=3D -1) { - return -1; + ret =3D -errno; + goto out; } =20 if ((flags & O_ACCMODE) =3D=3D (mon_fd_flags & O_ACCMODE)) { - return mon_fdset_fd->fd; + ret =3D mon_fdset_fd->fd; + goto out; } } - errno =3D EACCES; - return -1; + ret =3D -EACCES; + break; + } +out: + qemu_mutex_unlock(&mon_fdsets_lock); + /* + * qemu_mutex_unlock might pollute errno, so we translate the + * "ret" value into errno if error happened. + */ + if (ret < 0) { + errno =3D -ret; + ret =3D -1; } + return ret; #endif - - errno =3D ENOENT; - return -1; } =20 int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd) { MonFdset *mon_fdset; MonFdsetFd *mon_fdset_fd_dup; + int ret =3D -1; =20 + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { if (mon_fdset->id !=3D fdset_id) { continue; } QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) { if (mon_fdset_fd_dup->fd =3D=3D dup_fd) { - return -1; + ret =3D -1; + goto out; } } mon_fdset_fd_dup =3D g_malloc0(sizeof(*mon_fdset_fd_dup)); mon_fdset_fd_dup->fd =3D dup_fd; QLIST_INSERT_HEAD(&mon_fdset->dup_fds, mon_fdset_fd_dup, next); - return 0; + ret =3D 0; + break; } - return -1; + +out: + qemu_mutex_unlock(&mon_fdsets_lock); + return ret; } =20 static int monitor_fdset_dup_fd_find_remove(int dup_fd, bool remove) { MonFdset *mon_fdset; MonFdsetFd *mon_fdset_fd_dup; + int ret =3D -1; =20 + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) { if (mon_fdset_fd_dup->fd =3D=3D dup_fd) { @@ -2568,14 +2615,18 @@ static int monitor_fdset_dup_fd_find_remove(int dup= _fd, bool remove) if (QLIST_EMPTY(&mon_fdset->dup_fds)) { monitor_fdset_cleanup(mon_fdset); } - return -1; + ret =3D -1; + goto out; } else { - return mon_fdset->id; + ret =3D mon_fdset->id; + goto out; } } } } - return -1; +out: + qemu_mutex_unlock(&mon_fdsets_lock); + return ret; } =20 int monitor_fdset_dup_fd_find(int dup_fd) --=20 2.17.0