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, 8 insertions, 4 deletions

diff --git a/hw/qdev.c b/hw/qdev.c
index 0d3c0fc49c..afbc975b8f 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -28,6 +28,7 @@
 #include "net.h"
 #include "qdev.h"
 #include "sysemu.h"
+#include "error.h"
 
 int qdev_hotplug = 0;
 static bool qdev_hot_added = false;
@@ -182,19 +183,22 @@ void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id,
     dev->alias_required_for_version = required_for_version;
 }
 
-int qdev_unplug(DeviceState *dev)
+void qdev_unplug(DeviceState *dev, Error **errp)
 {
     DeviceClass *dc = DEVICE_GET_CLASS(dev);
 
     if (!dev->parent_bus->allow_hotplug) {
-        qerror_report(QERR_BUS_NO_HOTPLUG, dev->parent_bus->name);
-        return -1;
+        error_set(errp, QERR_BUS_NO_HOTPLUG, dev->parent_bus->name);
+        return;
     }
     assert(dc->unplug != NULL);
 
     qdev_hot_removed = true;
 
-    return dc->unplug(dev);
+    if (dc->unplug(dev) < 0) {
+        error_set(errp, QERR_UNDEFINED_ERROR);
+        return;
+    }
 }
 
 static int qdev_reset_one(DeviceState *dev, void *opaque)