Commit ef12a703 authored by Marc-André Lureau's avatar Marc-André Lureau Committed by Markus Armbruster
Browse files

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 >
9005b2a7). 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: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarMarkus Armbruster <armbru@redhat.com>
Message-Id: <20181205203737.9011-3-marcandre.lureau@redhat.com>
Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
parent 88e40e43

monitor.c

+19 −10
Original line number Diff line number Diff line
@@ -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.

             */

        AioContext *ctx;



        if (mon->use_io_thread) {

                aio_notify(iothread_get_aio_context(mon_iothread));

            }

            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);

}