From patchwork Thu May 24 04:39:49 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 919556 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 40rxX96l4Cz9s16 for ; Thu, 24 May 2018 14:40:41 +1000 (AEST) Received: from localhost ([::1]:36440 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi3L-0003Pr-KT for incoming@patchwork.ozlabs.org; Thu, 24 May 2018 00:40:39 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42583) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi2j-0003Oh-UX for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fLi2i-0008St-DN for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:01 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43344 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 1fLi2i-0008Si-8L for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:00 -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 C5722401EF03 for ; Thu, 24 May 2018 04:39:59 +0000 (UTC) Received: from xz-mi.redhat.com (ovpn-12-95.pek2.redhat.com [10.72.12.95]) by smtp.corp.redhat.com (Postfix) with ESMTP id 192412026609; Thu, 24 May 2018 04:39:56 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 24 May 2018 12:39:49 +0800 Message-Id: <20180524043952.11245-2-peterx@redhat.com> In-Reply-To: <20180524043952.11245-1-peterx@redhat.com> References: <20180524043952.11245-1-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 [10.11.55.5]); Thu, 24 May 2018 04:39:59 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 24 May 2018 04:39:59 +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 v7 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_Lureau?= Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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; }; /* Let's add monitor global variables to this struct. */ @@ -366,14 +371,14 @@ static gboolean monitor_unblocked(GIOChannel *chan, GIOCondition cond, { Monitor *mon = opaque; - qemu_mutex_lock(&mon->out_lock); + qemu_mutex_lock(&mon->mon_lock); mon->out_watch = 0; monitor_flush_locked(mon); - qemu_mutex_unlock(&mon->out_lock); + qemu_mutex_unlock(&mon->mon_lock); return FALSE; } -/* 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) 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); } /* flush at every end of line */ @@ -421,7 +426,7 @@ static void monitor_puts(Monitor *mon, const char *str) { char c; - qemu_mutex_lock(&mon->out_lock); + qemu_mutex_lock(&mon->mon_lock); for(;;) { c = *str++; if (c == '\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); } void monitor_vprintf(Monitor *mon, const char *fmt, va_list ap) @@ -725,7 +730,7 @@ static void monitor_data_init(Monitor *mon, bool skip_flush, 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 = 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_line, bool has_cpu_index, handle_hmp_command(&hmp, command_line); cur_mon = old_mon; - qemu_mutex_lock(&hmp.out_lock); + qemu_mutex_lock(&hmp.mon_lock); if (qstring_get_length(hmp.outbuf) > 0) { output = g_strdup(qstring_get_str(hmp.outbuf)); } else { output = g_strdup(""); } - qemu_mutex_unlock(&hmp.out_lock); + qemu_mutex_unlock(&hmp.mon_lock); out: monitor_data_destroy(&hmp); @@ -4377,9 +4382,9 @@ static void monitor_event(void *opaque, int event) switch (event) { case CHR_EVENT_MUX_IN: - qemu_mutex_lock(&mon->out_lock); + qemu_mutex_lock(&mon->mon_lock); mon->mux_out = 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 = 1; - qemu_mutex_unlock(&mon->out_lock); + qemu_mutex_unlock(&mon->mon_lock); break; case CHR_EVENT_OPENED: From patchwork Thu May 24 04:39:50 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 919557 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 40rxXK4ppLz9s0q for ; Thu, 24 May 2018 14:40:49 +1000 (AEST) Received: from localhost ([::1]:36442 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi3T-0003SU-0f for incoming@patchwork.ozlabs.org; Thu, 24 May 2018 00:40:47 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42601) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi2n-0003Qp-S3 for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fLi2m-0008UJ-Pc for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:05 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:57634 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 1fLi2m-0008UC-L4 for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:04 -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 3F3A77C6DE for ; Thu, 24 May 2018 04:40:04 +0000 (UTC) Received: from xz-mi.redhat.com (ovpn-12-95.pek2.redhat.com [10.72.12.95]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5DBE92024CA1; Thu, 24 May 2018 04:40:00 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 24 May 2018 12:39:50 +0800 Message-Id: <20180524043952.11245-3-peterx@redhat.com> In-Reply-To: <20180524043952.11245-1-peterx@redhat.com> References: <20180524043952.11245-1-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 [10.11.55.2]); Thu, 24 May 2018 04:40:04 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Thu, 24 May 2018 04:40:04 +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 v7 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_Lureau?= Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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; /* @@ -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; fd = qemu_chr_fe_get_msgfd(&cur_mon->chr); if (fd == -1) { @@ -2204,13 +2204,17 @@ void qmp_getfd(const char *fdname, Error **errp) return; } + qemu_mutex_lock(&cur_mon->mon_lock); QLIST_FOREACH(monfd, &cur_mon->fds, next) { if (strcmp(monfd->name, fdname) != 0) { continue; } - close(monfd->fd); + tmp_fd = monfd->fd; monfd->fd = fd; + qemu_mutex_unlock(&cur_mon->mon_lock); + /* Make sure close() is out of critical section */ + close(tmp_fd); return; } @@ -2219,24 +2223,31 @@ void qmp_getfd(const char *fdname, Error **errp) monfd->fd = fd; QLIST_INSERT_HEAD(&cur_mon->fds, monfd, next); + qemu_mutex_unlock(&cur_mon->mon_lock); } void qmp_closefd(const char *fdname, Error **errp) { mon_fd_t *monfd; + int tmp_fd; + qemu_mutex_lock(&cur_mon->mon_lock); QLIST_FOREACH(monfd, &cur_mon->fds, next) { if (strcmp(monfd->name, fdname) != 0) { continue; } QLIST_REMOVE(monfd, next); - close(monfd->fd); + tmp_fd = 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; } + qemu_mutex_unlock(&cur_mon->mon_lock); error_setg(errp, QERR_FD_NOT_FOUND, fdname); } @@ -2244,6 +2255,7 @@ int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp) { mon_fd_t *monfd; + qemu_mutex_lock(&mon->mon_lock); QLIST_FOREACH(monfd, &mon->fds, next) { int fd; @@ -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); return fd; } + qemu_mutex_unlock(&mon->mon_lock); error_setg(errp, "File descriptor named '%s' has not been found", fdname); return -1; } From patchwork Thu May 24 04:39:51 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 919558 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 40rxZq3rcPz9s0q for ; Thu, 24 May 2018 14:42:58 +1000 (AEST) Received: from localhost ([::1]:36452 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi5V-0005EJ-La for incoming@patchwork.ozlabs.org; Thu, 24 May 2018 00:42:53 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42634) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi2u-0003Wa-SV for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fLi2q-0008VH-0p for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:12 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33324 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 1fLi2p-0008V8-T3 for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:07 -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 80C92BB414 for ; Thu, 24 May 2018 04:40:07 +0000 (UTC) Received: from xz-mi.redhat.com (ovpn-12-95.pek2.redhat.com [10.72.12.95]) by smtp.corp.redhat.com (Postfix) with ESMTP id CAC51202660C; Thu, 24 May 2018 04:40:04 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 24 May 2018 12:39:51 +0800 Message-Id: <20180524043952.11245-4-peterx@redhat.com> In-Reply-To: <20180524043952.11245-1-peterx@redhat.com> References: <20180524043952.11245-1-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 [10.11.55.1]); Thu, 24 May 2018 04:40:07 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Thu, 24 May 2018 04:40:07 +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 v7 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_Lureau?= Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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 Reviewed-by: Stefan Hajnoczi --- monitor.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/monitor.c b/monitor.c index d6c3c08932..f01589f945 100644 --- a/monitor.c +++ b/monitor.c @@ -207,7 +207,16 @@ struct Monitor { int suspend_cnt; /* Needs to be accessed atomically */ bool skip_flush; bool use_io_thr; + + /* + * State used only in the thread "owning" the monitor. + * If @use_io_thr, this is mon_global.mon_iothread. + * Else, it's the main thread. + * These members can be safely accessed without locks. + */ ReadLineState *rs; + // other members that aren't shared + MonitorQMP qmp; gchar *mon_cpu_path; BlockCompletionFunc *password_completion_cb; @@ -1313,7 +1322,7 @@ void qmp_qmp_capabilities(bool has_enable, QMPCapabilityList *enable, cur_mon->qmp.commands = &qmp_commands; } -/* 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 +1336,7 @@ int monitor_set_cpu(int cpu_index) return 0; } +/* Callers must hold BQL. */ static CPUState *mon_get_cpu_sync(bool synchronize) { CPUState *cpu; From patchwork Thu May 24 04:39:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 919559 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 40rxcR2pb1z9s0q for ; Thu, 24 May 2018 14:44:23 +1000 (AEST) Received: from localhost ([::1]:36457 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi6u-0006E0-V9 for incoming@patchwork.ozlabs.org; Thu, 24 May 2018 00:44:20 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42635) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi2u-0003Wb-T4 for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fLi2t-000060-Em for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:12 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34352 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 1fLi2t-00005q-9g for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:11 -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 DF6F140BC049 for ; Thu, 24 May 2018 04:40:10 +0000 (UTC) Received: from xz-mi.redhat.com (ovpn-12-95.pek2.redhat.com [10.72.12.95]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1785B2026DEF; Thu, 24 May 2018 04:40:07 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 24 May 2018 12:39:52 +0800 Message-Id: <20180524043952.11245-5-peterx@redhat.com> In-Reply-To: <20180524043952.11245-1-peterx@redhat.com> References: <20180524043952.11245-1-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 [10.11.55.7]); Thu, 24 May 2018 04:40:10 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Thu, 24 May 2018 04:40:10 +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 v7 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_Lureau?= Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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. To make things simpler, we let monitor_fdset_get_fd() return the -errno directly when error happens, then in qemu_open() we translate it back into errno. Signed-off-by: Peter Xu --- monitor.c | 70 +++++++++++++++++++++++++++++++++++++++++----------- util/osdep.c | 3 ++- 2 files changed, 58 insertions(+), 15 deletions(-) diff --git a/monitor.c b/monitor.c index f01589f945..6266ff65c4 100644 --- a/monitor.c +++ b/monitor.c @@ -271,6 +271,9 @@ typedef struct QMPRequest QMPRequest; /* Protects mon_list, monitor_event_state. */ static QemuMutex monitor_lock; +/* 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; @@ -287,6 +290,16 @@ static QEMUClockType event_clock_type = QEMU_CLOCK_REALTIME; static void monitor_command_cb(void *opaque, const char *cmdline, void *readline_opaque); +/* + * 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? */ @@ -2316,9 +2329,11 @@ static void monitor_fdsets_cleanup(void) MonFdset *mon_fdset; MonFdset *mon_fdset_next; + 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); } AddfdInfo *qmp_add_fd(bool has_fdset_id, int64_t fdset_id, bool has_opaque, @@ -2353,6 +2368,7 @@ void qmp_remove_fd(int64_t fdset_id, bool has_fd, int64_t fd, Error **errp) MonFdsetFd *mon_fdset_fd; char fd_str[60]; + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { if (mon_fdset->id != fdset_id) { continue; @@ -2372,10 +2388,12 @@ void qmp_remove_fd(int64_t fdset_id, bool has_fd, int64_t fd, Error **errp) goto error; } monitor_fdset_cleanup(mon_fdset); + qemu_mutex_unlock(&mon_fdsets_lock); return; } error: + qemu_mutex_unlock(&mon_fdsets_lock); if (has_fd) { snprintf(fd_str, sizeof(fd_str), "fdset-id:%" PRId64 ", fd:%" PRId64, fdset_id, fd); @@ -2391,6 +2409,7 @@ FdsetInfoList *qmp_query_fdsets(Error **errp) MonFdsetFd *mon_fdset_fd; FdsetInfoList *fdset_list = NULL; + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { FdsetInfoList *fdset_info = g_malloc0(sizeof(*fdset_info)); FdsetFdInfoList *fdsetfd_list = NULL; @@ -2420,6 +2439,7 @@ FdsetInfoList *qmp_query_fdsets(Error **errp) fdset_info->next = fdset_list; fdset_list = fdset_info; } + qemu_mutex_unlock(&mon_fdsets_lock); return fdset_list; } @@ -2432,6 +2452,7 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdset_id, int64_t fdset_id, MonFdsetFd *mon_fdset_fd; AddfdInfo *fdinfo; + 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 */ @@ -2452,6 +2473,7 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdset_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 */ @@ -2502,16 +2524,21 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdset_id, int64_t fdset_id, fdinfo->fdset_id = mon_fdset->id; fdinfo->fd = mon_fdset_fd->fd; + qemu_mutex_unlock(&mon_fdsets_lock); return fdinfo; } int monitor_fdset_get_fd(int64_t fdset_id, int flags) { -#ifndef _WIN32 +#ifdef _WIN32 + return -ENOENT; +#else MonFdset *mon_fdset; MonFdsetFd *mon_fdset_fd; int mon_fd_flags; + int ret = -ENOENT; + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { if (mon_fdset->id != fdset_id) { continue; @@ -2519,49 +2546,60 @@ int monitor_fdset_get_fd(int64_t fdset_id, int flags) QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) { mon_fd_flags = fcntl(mon_fdset_fd->fd, F_GETFL); if (mon_fd_flags == -1) { - return -1; + ret = -errno; + goto out; } if ((flags & O_ACCMODE) == (mon_fd_flags & O_ACCMODE)) { - return mon_fdset_fd->fd; + ret = mon_fdset_fd->fd; + goto out; } } - errno = EACCES; - return -1; + ret = -EACCES; + break; } +out: + qemu_mutex_unlock(&mon_fdsets_lock); + return ret; #endif - - errno = ENOENT; - return -1; } int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd) { MonFdset *mon_fdset; MonFdsetFd *mon_fdset_fd_dup; + int ret = -1; + qemu_mutex_lock(&mon_fdsets_lock); QLIST_FOREACH(mon_fdset, &mon_fdsets, next) { if (mon_fdset->id != fdset_id) { continue; } QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) { if (mon_fdset_fd_dup->fd == dup_fd) { - return -1; + ret = -1; + goto out; } } mon_fdset_fd_dup = g_malloc0(sizeof(*mon_fdset_fd_dup)); mon_fdset_fd_dup->fd = dup_fd; QLIST_INSERT_HEAD(&mon_fdset->dup_fds, mon_fdset_fd_dup, next); - return 0; + ret = 0; + break; } - return -1; + +out: + qemu_mutex_unlock(&mon_fdsets_lock); + return ret; } static int monitor_fdset_dup_fd_find_remove(int dup_fd, bool remove) { MonFdset *mon_fdset; MonFdsetFd *mon_fdset_fd_dup; + int ret = -1; + 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 == dup_fd) { @@ -2570,14 +2608,18 @@ 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 = -1; + goto out; } else { - return mon_fdset->id; + ret = mon_fdset->id; + goto out; } } } } - return -1; +out: + qemu_mutex_unlock(&mon_fdsets_lock); + return ret; } int monitor_fdset_dup_fd_find(int dup_fd) diff --git a/util/osdep.c b/util/osdep.c index a73de0e1ba..ea51d500b6 100644 --- a/util/osdep.c +++ b/util/osdep.c @@ -302,7 +302,8 @@ int qemu_open(const char *name, int flags, ...) } fd = monitor_fdset_get_fd(fdset_id, flags); - if (fd == -1) { + if (fd < 0) { + errno = -fd; return -1; }