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, 2 insertions, 2 deletions

diff --git a/hw/xen_platform.c b/hw/xen_platform.c
index 5a7c4cc97b..a9c52a6e36 100644
--- a/hw/xen_platform.c
+++ b/hw/xen_platform.c
@@ -87,7 +87,7 @@ static void unplug_nic(PCIBus *b, PCIDevice *d)
 {
     if (pci_get_word(d->config + PCI_CLASS_DEVICE) ==
             PCI_CLASS_NETWORK_ETHERNET) {
-        qdev_unplug(&(d->qdev));
+        qdev_unplug(&(d->qdev), NULL);
     }
 }
 
@@ -100,7 +100,7 @@ static void unplug_disks(PCIBus *b, PCIDevice *d)
 {
     if (pci_get_word(d->config + PCI_CLASS_DEVICE) ==
             PCI_CLASS_STORAGE_IDE) {
-        qdev_unplug(&(d->qdev));
+        qdev_unplug(&(d->qdev), NULL);
     }
 }