Don't get XENBUS_SUSPEND callback registration on AdapterCount

Instances will not necessarily come and go in order so we can't know that
the last instance to go will be the one the registered the callback.
Instead register a callback for every instance and just use AdapterCount to
decide which instance writes distribution information to xenstore.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>

diff --git a/src/xennet/adapter.c b/src/xennet/adapter.c
index f1057249466d9199303354bc73602ca8087999a4..0b262d53122a464c0d202be1759354eeeb4ed4b6 100644 (file)
--- a/src/xennet/adapter.c
+++ b/src/xennet/adapter.c
@@ -1380,8 +1380,15 @@ AdapterSuspendCallbackLate(
     )
 {
     PXENNET_ADAPTER Adapter = Argument;
+    LONG            Count;
+
+    (VOID) InterlockedDecrement(&AdapterCount);
+
+    Count = InterlockedIncrement(&AdapterCount);
+    ASSERT(Count != 0);
 
-    (VOID) __AdapterSetDistribution(Adapter);
+    if (Count == 1)
+        (VOID) __AdapterSetDistribution(Adapter);
 }
 
 static NTSTATUS
@@ -1397,12 +1404,8 @@ AdapterSetDistribution(
     Count = InterlockedIncrement(&AdapterCount);
     ASSERT(Count != 0);
 
-    if (Count != 1)
-        goto done;
-
-    status = __AdapterSetDistribution(Adapter);
-    if (!NT_SUCCESS(status))
-        goto fail1;
+    if (Count == 1)
+        (VOID) __AdapterSetDistribution(Adapter);
 
     status = XENBUS_SUSPEND(Register,
                             &Adapter->SuspendInterface,
@@ -1411,20 +1414,19 @@ AdapterSetDistribution(
                             Adapter,
                             &Adapter->SuspendCallbackLate);
     if (!NT_SUCCESS(status))
-        goto fail2;
+        goto fail1;
 
-done:
     Trace("<====\n");
     return STATUS_SUCCESS;
 
-fail2:
-    Error("fail2\n");
-
-    __AdapterClearDistribution(Adapter);
-
 fail1:
     Error("fail1 (%08x)\n", status);
 
+    Count = InterlockedDecrement(&AdapterCount);
+
+    if (Count == 0)
+        __AdapterClearDistribution(Adapter);
+
     return status;
 }
 
@@ -1437,19 +1439,16 @@ AdapterClearDistribution(
 
     Trace("====>\n");
 
-    Count = InterlockedDecrement(&AdapterCount);
-
-    if (Count != 0)
-        goto done;
-
     XENBUS_SUSPEND(Deregister,
                    &Adapter->SuspendInterface,
                    Adapter->SuspendCallbackLate);
     Adapter->SuspendCallbackLate = NULL;
 
-    __AdapterClearDistribution(Adapter);
+    Count = InterlockedDecrement(&AdapterCount);
+
+    if (Count == 0)
+        __AdapterClearDistribution(Adapter);
 
-done:
     Trace("<====\n");
 }
 
@@ -1472,14 +1471,16 @@ AdapterEnable(
     if (!NT_SUCCESS(status))
         goto fail2;
 
-    (VOID) AdapterSetDistribution(Adapter);
+    status = AdapterSetDistribution(Adapter);
+    if (!NT_SUCCESS(status))
+        goto fail3;
 
     status = XENVIF_VIF(Enable,
                         &Adapter->VifInterface,
                         AdapterVifCallback,
                         Adapter);
     if (!NT_SUCCESS(status))
-        goto fail3;
+        goto fail4;
 
     AdapterMediaStateChange(Adapter);
 
@@ -1487,9 +1488,10 @@ AdapterEnable(
 
     return NDIS_STATUS_SUCCESS;
 
-fail3:
+fail4:
     AdapterClearDistribution(Adapter);
 
+fail3:
     XENBUS_SUSPEND(Release, &Adapter->SuspendInterface);
 
 fail2: