From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33985) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eM6BD-000420-Mu for qemu-devel@nongnu.org; Tue, 05 Dec 2017 00:54:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eM6BC-0002B3-UE for qemu-devel@nongnu.org; Tue, 05 Dec 2017 00:54:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57108) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eM6BC-0002Af-OJ for qemu-devel@nongnu.org; Tue, 05 Dec 2017 00:54:06 -0500 From: Peter Xu Date: Tue, 5 Dec 2017 13:51:49 +0800 Message-Id: <20171205055200.16305-16-peterx@redhat.com> In-Reply-To: <20171205055200.16305-1-peterx@redhat.com> References: <20171205055200.16305-1-peterx@redhat.com> Subject: [Qemu-devel] [RFC v5 15/26] monitor: let suspend_cnt be thread safe List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi , "Daniel P . Berrange" , Paolo Bonzini , Fam Zheng , Juan Quintela , mdroth@linux.vnet.ibm.com, peterx@redhat.com, Eric Blake , Laurent Vivier , Markus Armbruster , marcandre.lureau@redhat.com, "Dr . David Alan Gilbert" Monitor code now can be run in more than one thread. Let it be thread safe when accessing suspend_cnt counter. Signed-off-by: Peter Xu --- monitor.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/monitor.c b/monitor.c index 35d8925636..6ac1b2065d 100644 --- a/monitor.c +++ b/monitor.c @@ -3874,7 +3874,7 @@ static int monitor_can_read(void *opaque) { Monitor *mon = opaque; - return (mon->suspend_cnt == 0) ? 1 : 0; + return (atomic_read(&mon->suspend_cnt) == 0) ? 1 : 0; } /* @@ -4003,7 +4003,7 @@ int monitor_suspend(Monitor *mon) { if (!mon->rs) return -ENOTTY; - mon->suspend_cnt++; + atomic_inc(&mon->suspend_cnt); return 0; } @@ -4011,8 +4011,9 @@ void monitor_resume(Monitor *mon) { if (!mon->rs) return; - if (--mon->suspend_cnt == 0) + if (atomic_dec_fetch(&mon->suspend_cnt) == 0) { readline_show_prompt(mon->rs); + } } static QObject *get_qmp_greeting(void) @@ -4078,19 +4079,19 @@ static void monitor_event(void *opaque, int event) monitor_resume(mon); monitor_flush(mon); } else { - mon->suspend_cnt = 0; + atomic_set(&mon->suspend_cnt, 0); } break; case CHR_EVENT_MUX_OUT: if (mon->reset_seen) { - if (mon->suspend_cnt == 0) { + if (atomic_read(&mon->suspend_cnt) == 0) { monitor_printf(mon, "\n"); } monitor_flush(mon); monitor_suspend(mon); } else { - mon->suspend_cnt++; + atomic_inc(&mon->suspend_cnt); } qemu_mutex_lock(&mon->out_lock); mon->mux_out = 1; -- 2.14.3