scsi: introduce hotplug() and hot_unplug() interfaces for SCSI bus

Add two interfaces hotplug() and hot_unplug() to scsi bus info.
The scsi bus can implement these two interfaces to signal the HBA driver
of guest kernel to add/remove the scsi device in question.
Signed-off-by: NSen Wang <senwang@linux.vnet.ibm.com>
Signed-off-by: NCong Meng <mc@linux.vnet.ibm.com>
[ Fixed braces and indentation - Paolo ]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi-bus.c

@@ -186,6 +186,10 @@ static int scsi_qdev_init(DeviceState *qdev)
                                                          dev);
     }
 
+    if (bus->info->hotplug) {
+        bus->info->hotplug(bus, dev);
+    }
+
 err:
     return rc;
 }
@@ -1650,6 +1654,17 @@ static int get_scsi_requests(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
+static int scsi_qdev_unplug(DeviceState *qdev)
+{
+    SCSIDevice *dev = SCSI_DEVICE(qdev);
+    SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
+
+    if (bus->info->hot_unplug) {
+        bus->info->hot_unplug(bus, dev);
+    }
+    return qdev_simple_unplug_cb(qdev);
+}
+
 static const VMStateInfo vmstate_info_scsi_requests = {
     .name = "scsi-requests",
     .get  = get_scsi_requests,
@@ -1686,7 +1701,7 @@ static void scsi_device_class_init(ObjectClass *klass, void *data)
     DeviceClass *k = DEVICE_CLASS(klass);
     k->bus_type = TYPE_SCSI_BUS;
     k->init     = scsi_qdev_init;
-    k->unplug   = qdev_simple_unplug_cb;
+    k->unplug   = scsi_qdev_unplug;
     k->exit     = scsi_qdev_exit;
     k->props    = scsi_props;
 }

hw/scsi.h

@@ -131,6 +131,8 @@ struct SCSIBusInfo {
     void (*transfer_data)(SCSIRequest *req, uint32_t arg);
     void (*complete)(SCSIRequest *req, uint32_t arg, size_t resid);
     void (*cancel)(SCSIRequest *req);
+    void (*hotplug)(SCSIBus *bus, SCSIDevice *dev);
+    void (*hot_unplug)(SCSIBus *bus, SCSIDevice *dev);
     QEMUSGList *(*get_sg_list)(SCSIRequest *req);
 
     void (*save_request)(QEMUFile *f, SCSIRequest *req);