[PATCH] Correct return codes during racy destruction (3).

[Martin Harvey <Martin.Harvey@xxxxxxxxxx>]

Errors in PnP retun codes found when testing under driver
verifier with mixed VM lifecycle operations. Under some
rare cases, it is possible to get more than one PnP
"remove like" operation. This results in a PnP remove
operation being processed whilst the device is already
in the deleted state.

This patch fixes the immediate cause of the bugfixes,
buy fixing the return code. Device destruction is
unchanged. Investigation into the root cause is still
ongoing.

Signed-off-by: Martin Harvey <martin.harvey@xxxxxxxxxx>
---
 src/xendisk/driver.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/xendisk/driver.c b/src/xendisk/driver.c
index 4b004c5..c165c90 100644
--- a/src/xendisk/driver.c
+++ b/src/xendisk/driver.c
@@ -170,8 +170,20 @@ Dispatch(
     ASSERT3P(Dx->DeviceObject, ==, DeviceObject);
 
     if (Dx->DevicePnpState == Deleted) {
+        PIO_STACK_LOCATION StackLocation = IoGetCurrentIrpStackLocation(Irp);
+        UCHAR MajorFunction = StackLocation->MajorFunction;
+        UCHAR MinorFunction = StackLocation->MinorFunction;
         status = STATUS_NO_SUCH_DEVICE;
 
+        if (MajorFunction == IRP_MJ_PNP) {
+            if ((MinorFunction == IRP_MN_SURPRISE_REMOVAL) ||
+               (MinorFunction == IRP_MN_REMOVE_DEVICE)) {
+                /* FDO and PDO deletions can block after being marked deleted, 
but before IoDeleteDevice */
+                status = STATUS_SUCCESS;
+            }
+            ASSERT((MinorFunction != IRP_MN_CANCEL_REMOVE_DEVICE) && 
(MinorFunction != IRP_MN_CANCEL_STOP_DEVICE));
+        }
+
         Irp->IoStatus.Status = status;
         IoCompleteRequest(Irp, IO_NO_INCREMENT);
         goto done;
-- 
2.25.0.windows.1