qdev: qdev_unplug(): use error_set()

It currently uses qerror_report(), but next commit will convert
the drive_del command to the QAPI and this requires using
error_set().

One particularity of qerror_report() is that it knows when it's
running on monitor context or command-line context and prints the
error message accordingly. error_set() doesn't do this, so we
have to be careful not to drop error messages.

qdev_unplug() has three kinds of usages:

 1. It's called when hot adding a device fails, to undo anything
    that has been done before hitting the error

 2. It's called by function monitor functions like device_del(),
    to unplug a device

 3. It's used by xen_platform.c in a way that doesn't _seem_ to
    be in monitor context

Only item 2 can print an error message to the user, this commit
maintains that.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/hw/qdev-monitor.c b/hw/qdev-monitor.c
index 4783366cf4..fd56afed45 100644
--- a/hw/qdev-monitor.c
+++ b/hw/qdev-monitor.c
@@ -573,6 +573,7 @@ int do_device_add(Monitor *mon, const QDict *qdict, QObject **ret_data)
 int do_device_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     const char *id = qdict_get_str(qdict, "id");
+    Error *local_err = NULL;
     DeviceState *dev;
 
     dev = qdev_find_recursive(sysbus_get_default(), id);
@@ -580,7 +581,15 @@ int do_device_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
         qerror_report(QERR_DEVICE_NOT_FOUND, id);
         return -1;
     }
-    return qdev_unplug(dev);
+
+    qdev_unplug(dev, &local_err);
+    if (error_is_set(&local_err)) {
+        qerror_report_err(local_err);
+        error_free(local_err);
+        return -1;
+    }
+
+    return 0;
 }
 
 void qdev_machine_init(void)