monitor: accept chardev input from iothread

Chardev backends may not handle safely IO events from concurrent
threads (may not handle I/O events from concurrent threads safely,
only the write path is since commit >
9005b2a758). Better to wake up the
chardev from the monitor IO thread if it's being used as the chardev
context.

Unify code paths by using a BH in all cases.

Drop the now redundant aio_notify() call.

Clean up control flow not to rely on mon->use_io_thread implying
monitor_is_qmp(mon).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20181205203737.9011-3-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
Marc-André Lureau 2018-12-06 00:37:32 +04:00 committed by Markus Armbruster
parent 88e40e4347
commit ef12a703b7

View File

@ -4297,7 +4297,7 @@ int monitor_suspend(Monitor *mon)
atomic_inc(&mon->suspend_cnt);
if (monitor_is_qmp(mon) && mon->use_io_thread) {
if (mon->use_io_thread) {
/*
* Kick I/O thread to make sure this takes effect. It'll be
* evaluated again in prepare() of the watch object.
@ -4309,6 +4309,13 @@ int monitor_suspend(Monitor *mon)
return 0;
}
static void monitor_accept_input(void *opaque)
{
Monitor *mon = opaque;
qemu_chr_fe_accept_input(&mon->chr);
}
void monitor_resume(Monitor *mon)
{
if (monitor_is_hmp_non_interactive(mon)) {
@ -4316,20 +4323,22 @@ void monitor_resume(Monitor *mon)
}
if (atomic_dec_fetch(&mon->suspend_cnt) == 0) {
if (monitor_is_qmp(mon)) {
/*
* For QMP monitors that are running in the I/O thread,
* let's kick the thread in case it's sleeping.
*/
if (mon->use_io_thread) {
aio_notify(iothread_get_aio_context(mon_iothread));
}
AioContext *ctx;
if (mon->use_io_thread) {
ctx = iothread_get_aio_context(mon_iothread);
} else {
ctx = qemu_get_aio_context();
}
if (!monitor_is_qmp(mon)) {
assert(mon->rs);
readline_show_prompt(mon->rs);
}
qemu_chr_fe_accept_input(&mon->chr);
aio_bh_schedule_oneshot(ctx, monitor_accept_input, mon);
}
trace_monitor_suspend(mon, -1);
}