[PATCH] Ensure the PV ring is drained on disconnect

[Mark Syms]

Also ensure all pending AIO is complete.

Signed-off-by: Mark Syms <mark.syms@citrix.com>
---
 hw/block/dataplane/xen-block.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
index 734da42ea7..067f8e2f45 100644
--- a/hw/block/dataplane/xen-block.c
+++ b/hw/block/dataplane/xen-block.c
@@ -523,6 +523,10 @@ static bool xen_block_handle_requests(XenBlockDataPlane 
*dataplane)
 
     dataplane->more_work = 0;
 
+    if (dataplane->sring == 0) {
+        return done_something;
+    }
+
     rc = dataplane->rings.common.req_cons;
     rp = dataplane->rings.common.sring->req_prod;
     xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
@@ -666,11 +670,23 @@ void xen_block_dataplane_destroy(XenBlockDataPlane 
*dataplane)
 void xen_block_dataplane_stop(XenBlockDataPlane *dataplane)
 {
     XenDevice *xendev;
+    XenBlockRequest *request, *next;
 
     if (!dataplane) {
         return;
     }
 
+    /* Ensure we have drained the ring */
+    do {
+        xen_block_handle_requests(dataplane);
+    } while (dataplane->more_work);
+
+    /* Now ensure that all inflight requests are complete */
+    QLIST_FOREACH_SAFE(request, &dataplane->inflight, list, next) {
+        blk_aio_flush(request->dataplane->blk, xen_block_complete_aio,
+                      request);
+    }
+
     xendev = dataplane->xendev;
 
     aio_context_acquire(dataplane->ctx);
-- 
2.39.2