Fix PdoReset by attempting to poll ring for up to 5 minutes before bugchecking

Signed-off-by: Owen Smith <owen.smith@citrix.com>

diff --git a/src/xenvbd/granter.c b/src/xenvbd/granter.c
index 6103c7f664caf72a229af17f70ababb2a6cf73c7..c5d39b07d304971aea6dc06bbb379cfd2f5efc76 100644 (file)
--- a/src/xenvbd/granter.c
+++ b/src/xenvbd/granter.c
@@ -267,6 +267,10 @@ GranterGet(
     NTSTATUS                    status;
     LONG                        Value;
 
+    status = STATUS_DEVICE_NOT_READY;
+    if (Granter->Enabled == FALSE)
+        goto fail1;
+
     status = GNTTAB(PermitForeignAccess, 
                     Granter->GnttabInterface, 
                     Granter->Cache,
@@ -276,7 +280,7 @@ GranterGet(
                     ReadOnly,
                     &Descriptor);
     if (!NT_SUCCESS(status))
-        goto fail1;
+        goto fail2;
     
     Value = InterlockedIncrement(&Granter->Current);
     if (Value > Granter->Maximum)
@@ -285,6 +289,7 @@ GranterGet(
     *Handle = Descriptor;
     return STATUS_SUCCESS;
 
+fail2:
 fail1:
     return status;
 }
@@ -298,6 +303,9 @@ GranterPut(
     PXENBUS_GNTTAB_DESCRIPTOR   Descriptor = Handle;
     NTSTATUS                    status;
 
+    if (Granter->Enabled == FALSE)
+        return;
+
     status = GNTTAB(RevokeForeignAccess,
                     Granter->GnttabInterface,
                     Granter->Cache,
@@ -316,5 +324,8 @@ GranterReference(
 {
     PXENBUS_GNTTAB_DESCRIPTOR   Descriptor = Handle;
 
+    if (Granter->Enabled == FALSE)
+        return 0;
+
     return GNTTAB(Reference, Granter->GnttabInterface, Descriptor);
 }

diff --git a/src/xenvbd/pdo.c b/src/xenvbd/pdo.c
index 16207eb2a2e7865dc18630bad16e82bd6e9a085f..a4d9c3bf9808ebb61d47d9bec80b9018ed329d2b 100644 (file)
--- a/src/xenvbd/pdo.c
+++ b/src/xenvbd/pdo.c
@@ -447,27 +447,37 @@ __PdoRestoreDevicePnpState(
     }
 }
 
-__drv_maxIRQL(APC_LEVEL)
 static FORCEINLINE VOID
 __PdoPauseDataPath(
-    __in PXENVBD_PDO             Pdo
+    __in PXENVBD_PDO             Pdo,
+    __in BOOLEAN                 Timeout
     )
 {
     KIRQL               Irql;
-    LARGE_INTEGER       Timeout;
+    ULONG               Requests;
+    ULONG               Count = 0;
     PXENVBD_NOTIFIER    Notifier = FrontendGetNotifier(Pdo->Frontend);
 
     KeAcquireSpinLock(&Pdo->Lock, &Irql);
     ++Pdo->Paused;
     KeReleaseSpinLock(&Pdo->Lock, Irql);
 
-    Verbose("Target[%d] : Waiting for %d Submitted requests\n", PdoGetTargetId(Pdo), QueueCount(&Pdo->SubmittedReqs));
+    Requests = QueueCount(&Pdo->SubmittedReqs);
+    KeMemoryBarrier();
+
+    Verbose("Target[%d] : Waiting for %d Submitted requests\n", PdoGetTargetId(Pdo), Requests);
 
-    Timeout.QuadPart = -10000000;
     while (QueueCount(&Pdo->SubmittedReqs)) {
-        NotifierSend(Notifier); // let backend know it needs to do some work
-        KeDelayExecutionThread(KernelMode, FALSE, &Timeout);
+        if (Timeout && Count > 60000)
+            break;
+        FrontendNotifyResponses(Pdo->Frontend);
+        NotifierSend(Notifier);         // let backend know it needs to do some work
+        StorPortStallExecution(500);    // 500 micro-seconds
+        ++Count;
     }
+
+    Verbose("Target[%d] : %u/%u Submitted requests left (%u iterrations)\n",
+            PdoGetTargetId(Pdo), QueueCount(&Pdo->SubmittedReqs), Requests, Count);
 }
 
 static FORCEINLINE VOID
@@ -691,7 +701,7 @@ PdoD0ToD3(
 
     // close frontend
     if (Pdo->EmulatedUnplugged) {
-        __PdoPauseDataPath(Pdo);
+        __PdoPauseDataPath(Pdo, FALSE);
         (VOID) FrontendSetState(Pdo->Frontend, XENVBD_CLOSED);
         PdoAbortAllSrbs(Pdo);
         ASSERT3U(QueueCount(&Pdo->SubmittedReqs), ==, 0);
@@ -2274,46 +2284,30 @@ PdoReset(
     __in PXENVBD_PDO             Pdo
     )
 {
-    ULONG               Count;
-    PXENVBD_NOTIFIER    Notifier = FrontendGetNotifier(Pdo->Frontend);
+    NTSTATUS        Status;
 
     Trace("Target[%d] ====> (Irql=%d)\n", PdoGetTargetId(Pdo), KeGetCurrentIrql());
 
-    // Handles FreshSrbs and PreparedReqs
-    PdoAbortAllSrbs(Pdo);
+    // poll until SubmittedReqs are complete, dont submit any new requests
+    __PdoPauseDataPath(Pdo, TRUE);
 
-    // SubmittedReqs (5 secs)
-    for (Count = 0; QueueCount(&Pdo->SubmittedReqs) && Count < 50000; ++Count) {
-        FrontendNotifyResponses(Pdo->Frontend);
-        NotifierSend(Notifier);
-        StorPortStallExecution(100); // 100 micro-seconds
-    }
+    // if there are submitted reqs left, BSOD, its the only way to be sure
     if (QueueCount(&Pdo->SubmittedReqs)) {
-        Warning("Target[%d] : Still have %u requests outstanding\n", PdoGetTargetId(Pdo),
-                                QueueCount(&Pdo->SubmittedReqs));
-
-        for (;;) {
-            PXENVBD_SRBEXT  SrbExt;
-            PXENVBD_REQUEST Request;
-            PLIST_ENTRY     Entry = QueuePop(&Pdo->SubmittedReqs);
-            if (Entry == NULL)
-                break;
-            Request = CONTAINING_RECORD(Entry, XENVBD_REQUEST, Entry);
-            SrbExt = GetSrbExt(Request->Srb);
-
-            Verbose("Target[%d] : SubmittedReq 0x%p -> FAILED\n", PdoGetTargetId(Pdo), Request);
-        
-            SrbExt->Srb->SrbStatus = SRB_STATUS_ABORTED;
-            RequestCleanup(Pdo, Request);
-            __LookasideFree(&Pdo->RequestList, Request);
-
-            if (InterlockedDecrement(&SrbExt->Count) == 0) {
-                SrbExt->Srb->ScsiStatus = 0x40; // SCSI_ABORTED
-                FdoCompleteSrb(PdoGetFdo(Pdo), SrbExt->Srb);
-            }
-        }
+        BUG("backend contains outstanding requests after reset");
     }
 
+    Status = FrontendSetState(Pdo->Frontend, XENVBD_CLOSED);
+    ASSERT(NT_SUCCESS(Status));
+
+    // unprepare all PreparedReqs and abort all FreshSrbs
+    PdoAbortAllSrbs(Pdo);
+    ASSERT3U(QueueCount(&Pdo->SubmittedReqs), ==, 0);
+
+    Status = FrontendSetState(Pdo->Frontend, XENVBD_ENABLED);
+    ASSERT(NT_SUCCESS(Status));
+
+    __PdoUnpauseDataPath(Pdo);
+
     Trace("Target[%d] <==== (Irql=%d)\n", PdoGetTargetId(Pdo), KeGetCurrentIrql());
 }