[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v7 12/23] monitor: let suspend_cnt be thread safe
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH v7 12/23] monitor: let suspend_cnt be thread safe |
Date: |
Wed, 24 Jan 2018 13:39:46 +0800 |
Monitor code now can be run in more than one thread. Let it be thread
safe when accessing suspend_cnt counter.
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Peter Xu <address@hidden>
---
monitor.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/monitor.c b/monitor.c
index 92114aaa80..60bcf67b3a 100644
--- a/monitor.c
+++ b/monitor.c
@@ -190,7 +190,7 @@ struct Monitor {
CharBackend chr;
int reset_seen;
int flags;
- int suspend_cnt;
+ int suspend_cnt; /* Needs to be accessed atomically */
bool skip_flush;
bool use_io_thr;
@@ -3864,7 +3864,7 @@ static int monitor_can_read(void *opaque)
{
Monitor *mon = opaque;
- return (mon->suspend_cnt == 0) ? 1 : 0;
+ return !atomic_mb_read(&mon->suspend_cnt);
}
/*
@@ -3996,7 +3996,7 @@ int monitor_suspend(Monitor *mon)
{
if (!mon->rs)
return -ENOTTY;
- mon->suspend_cnt++;
+ atomic_inc(&mon->suspend_cnt);
return 0;
}
@@ -4004,8 +4004,9 @@ 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(Monitor *mon)
@@ -4070,19 +4071,19 @@ static void monitor_event(void *opaque, int event)
monitor_resume(mon);
monitor_flush(mon);
} else {
- mon->suspend_cnt = 0;
+ atomic_mb_set(&mon->suspend_cnt, 0);
}
break;
case CHR_EVENT_MUX_OUT:
if (mon->reset_seen) {
- if (mon->suspend_cnt == 0) {
+ if (atomic_mb_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
- [Qemu-devel] [PATCH v7 02/23] qobject: introduce qstring_get_try_str(), (continued)
- [Qemu-devel] [PATCH v7 02/23] qobject: introduce qstring_get_try_str(), Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 03/23] qobject: introduce qobject_get_try_str(), Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 04/23] qobject: let object_property_get_str() use new API, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 05/23] monitor: move skip_flush into monitor_data_init, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 06/23] monitor: move the cur_mon hack deeper for QMP, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 07/23] monitor: unify global init, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 08/23] monitor: let mon_list be tail queue, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 09/23] monitor: allow using IO thread for parsing, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 10/23] qmp: introduce QMPCapability, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 11/23] monitor: introduce monitor_qmp_respond(), Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 12/23] monitor: let suspend_cnt be thread safe,
Peter Xu <=
- [Qemu-devel] [PATCH v7 13/23] monitor: let suspend/resume work even with QMPs, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 14/23] monitor: separate QMP parser and dispatcher, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 15/23] qmp: add new event "command-dropped", Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 16/23] monitor: send event when command queue full, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 17/23] qapi: introduce new cmd option "allow-oob", Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 18/23] qmp: support out-of-band (oob) execution, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 19/23] qmp: isolate responses into io thread, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 20/23] monitor: enable IO thread for (qmp & !mux) typed, Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 21/23] qmp: add command "x-oob-test", Peter Xu, 2018/01/24
- [Qemu-devel] [PATCH v7 22/23] tests: qmp-test: verify command batching, Peter Xu, 2018/01/24