1 files changed, 40 insertions, 0 deletions
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index 64013c8a24..f80f4cb4fc 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -1669,6 +1669,46 @@ void scsi_device_purge_requests(SCSIDevice *sdev, SCSISense sense)
     scsi_device_set_ua(sdev, sense);
 }
 
+void scsi_device_drained_begin(SCSIDevice *sdev)
+{
+    SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, sdev->qdev.parent_bus);
+    if (!bus) {
+        return;
+    }
+
+    assert(qemu_get_current_aio_context() == qemu_get_aio_context());
+    assert(bus->drain_count < INT_MAX);
+
+    /*
+     * Multiple BlockBackends can be on a SCSIBus and each may begin/end
+     * draining at any time. Keep a counter so HBAs only see begin/end once.
+     */
+    if (bus->drain_count++ == 0) {
+        trace_scsi_bus_drained_begin(bus, sdev);
+        if (bus->info->drained_begin) {
+            bus->info->drained_begin(bus);
+        }
+    }
+}
+
+void scsi_device_drained_end(SCSIDevice *sdev)
+{
+    SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, sdev->qdev.parent_bus);
+    if (!bus) {
+        return;
+    }
+
+    assert(qemu_get_current_aio_context() == qemu_get_aio_context());
+    assert(bus->drain_count > 0);
+
+    if (bus->drain_count-- == 1) {
+        trace_scsi_bus_drained_end(bus, sdev);
+        if (bus->info->drained_end) {
+            bus->info->drained_end(bus);
+        }
+    }
+}
+
 static char *scsibus_get_dev_path(DeviceState *dev)
 {
     SCSIDevice *d = SCSI_DEVICE(dev);