1 files changed, 31 insertions, 11 deletions

diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
index d8bc39d359..2597f38805 100644
--- a/hw/block/dataplane/xen-block.c
+++ b/hw/block/dataplane/xen-block.c
@@ -664,6 +664,30 @@ void xen_block_dataplane_destroy(XenBlockDataPlane *dataplane)
     g_free(dataplane);
 }
 
+void xen_block_dataplane_detach(XenBlockDataPlane *dataplane)
+{
+    if (!dataplane || !dataplane->event_channel) {
+        return;
+    }
+
+    /* Only reason for failure is a NULL channel */
+    xen_device_set_event_channel_context(dataplane->xendev,
+                                         dataplane->event_channel,
+                                         NULL, &error_abort);
+}
+
+void xen_block_dataplane_attach(XenBlockDataPlane *dataplane)
+{
+    if (!dataplane || !dataplane->event_channel) {
+        return;
+    }
+
+    /* Only reason for failure is a NULL channel */
+    xen_device_set_event_channel_context(dataplane->xendev,
+                                         dataplane->event_channel,
+                                         dataplane->ctx, &error_abort);
+}
+
 void xen_block_dataplane_stop(XenBlockDataPlane *dataplane)
 {
     XenDevice *xendev;
@@ -674,13 +698,11 @@ void xen_block_dataplane_stop(XenBlockDataPlane *dataplane)
 
     xendev = dataplane->xendev;
 
-    aio_context_acquire(dataplane->ctx);
-    if (dataplane->event_channel) {
-        /* Only reason for failure is a NULL channel */
-        xen_device_set_event_channel_context(xendev, dataplane->event_channel,
-                                             qemu_get_aio_context(),
-                                             &error_abort);
+    if (!blk_in_drain(dataplane->blk)) {
+        xen_block_dataplane_detach(dataplane);
     }
+
+    aio_context_acquire(dataplane->ctx);
     /* Xen doesn't have multiple users for nodes, so this can't fail */
     blk_set_aio_context(dataplane->blk, qemu_get_aio_context(), &error_abort);
     aio_context_release(dataplane->ctx);
@@ -819,11 +841,9 @@ void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
     blk_set_aio_context(dataplane->blk, dataplane->ctx, NULL);
     aio_context_release(old_context);
 
-    /* Only reason for failure is a NULL channel */
-    aio_context_acquire(dataplane->ctx);
-    xen_device_set_event_channel_context(xendev, dataplane->event_channel,
-                                         dataplane->ctx, &error_abort);
-    aio_context_release(dataplane->ctx);
+    if (!blk_in_drain(dataplane->blk)) {
+        xen_block_dataplane_attach(dataplane);
+    }
 
     return;