From: Paul Durrant <paul.durrant@citrix.com>
Date: Tue, 8 Dec 2015 15:06:51 +0000 (+0000)
Subject: Don't get XENBUS_SUSPEND callback registration on AdapterCount
X-Git-Tag: 8.1.0-rc7^0
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=7e10b0af37a44db6b9c98b0fcb97d22171579a9f;p=pvdrivers%2Fwin%2Fxennet.git

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 f105724..0b262d5 100644
--- 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: