diff options
author | Peter Xu <peterx@redhat.com> | 2018-03-09 16:59:55 +0800 |
---|---|---|
committer | Eric Blake <eblake@redhat.com> | 2018-03-19 14:58:37 -0500 |
commit | df152fb950e3e00d0186cbdc412dc8ddcc618621 (patch) | |
tree | c57d0301cf69e0d82dc34581ebc8864b3a4727e1 | |
parent | 546aa56674305a4ab45bea4f36956651fd892b04 (diff) | |
download | qemu-df152fb950e3e00d0186cbdc412dc8ddcc618621.zip qemu-df152fb950e3e00d0186cbdc412dc8ddcc618621.tar.gz qemu-df152fb950e3e00d0186cbdc412dc8ddcc618621.tar.bz2 |
monitor: let suspend_cnt be thread safe
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 <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180309090006.10018-13-peterx@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
-rw-r--r-- | monitor.c | 15 |
1 files changed, 8 insertions, 7 deletions
@@ -194,7 +194,7 @@ 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; @@ -3819,7 +3819,7 @@ static int monitor_can_read(void *opaque) { Monitor *mon = opaque; - return (mon->suspend_cnt == 0) ? 1 : 0; + return !atomic_mb_read(&mon->suspend_cnt); } /* @@ -3951,7 +3951,7 @@ int monitor_suspend(Monitor *mon) { if (!mon->rs) return -ENOTTY; - mon->suspend_cnt++; + atomic_inc(&mon->suspend_cnt); return 0; } @@ -3959,8 +3959,9 @@ 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) @@ -4025,19 +4026,19 @@ 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; |