From 8b44caccfed5d8c68c72e13c09ee0930e35df78d Mon Sep 17 00:00:00 2001
From: Owen Smith <owen.smith@citrix.com>
Date: Wed, 2 Dec 2015 15:16:49 +0000
Subject: [PATCH] Remove BlockRing.Outstanding / BlockRingAbort

The BlockRing Outstanding stat is duplicated by SubmittedReqs.Count.
Remove BlockRing.Outstanding and the BlockRingAbort function as the
stat is not useful, and can trigger ASSERTion failures when requests
are stuck outstanding on a broken ring that is being destroyed.

Signed-off-by: Owen Smith <owen.smith@citrix.com>
---
 src/xenvbd/blockring.c | 28 +---------------------------
 src/xenvbd/blockring.h |  6 ------
 src/xenvbd/pdo.c       |  4 +---
 3 files changed, 2 insertions(+), 36 deletions(-)

diff --git a/src/xenvbd/blockring.c b/src/xenvbd/blockring.c
index 28f1393..6e07f09 100644
--- a/src/xenvbd/blockring.c
+++ b/src/xenvbd/blockring.c
@@ -56,7 +56,6 @@ struct _XENVBD_BLOCKRING {
     ULONG                           DeviceId;
     ULONG                           Order;
     PVOID                           Grants[XENVBD_MAX_RING_PAGES];
-    ULONG                           Outstanding;
     ULONG                           Submitted;
     ULONG                           Received;
 };
@@ -235,7 +234,6 @@ __BlockRingInsert(
         break;
     }
     ++BlockRing->Submitted;
-    ++BlockRing->Outstanding;
 }
 
 NTSTATUS
@@ -432,7 +430,6 @@ BlockRingDisconnect(
     PXENVBD_GRANTER Granter = FrontendGetGranter(BlockRing->Frontend);
 
     ASSERT(BlockRing->Connected == TRUE);
-    ASSERT3U(BlockRing->Outstanding, ==, 0);
 
     BlockRing->Submitted = 0;
     BlockRing->Received = 0;
@@ -467,8 +464,7 @@ BlockRingDebugCallback(
     PXENVBD_GRANTER Granter = FrontendGetGranter(BlockRing->Frontend);
 
     XENBUS_DEBUG(Printf, Debug,
-                 "BLOCKRING: Requests  : %d / %d / %d\n",
-                 BlockRing->Outstanding,
+                 "BLOCKRING: Requests  : %d / %d\n",
                  BlockRing->Submitted,
                  BlockRing->Received);
 
@@ -543,7 +539,6 @@ BlockRingPoll(
 
             if (__BlockRingPutTag(BlockRing, Response->id, &Tag)) {
                 ++BlockRing->Received;
-                --BlockRing->Outstanding;
                 PdoCompleteResponse(Pdo, Tag, Response->status);
             }
 
@@ -589,24 +584,3 @@ BlockRingSubmit(
 
     return TRUE;
 }
-
-VOID
-BlockRingAbort(
-    IN  PXENVBD_BLOCKRING           BlockRing,
-    IN  PXENVBD_REQUEST             Request
-    )
-{
-    KIRQL               Irql;
-
-    UNREFERENCED_PARAMETER(Request);
-
-    KeAcquireSpinLock(&BlockRing->Lock, &Irql);
-
-    // Should check Request is present on the ring, but
-    // the shared page(s) may not contain any valid data,
-    // due to suspend/resume
-    ASSERT3U(BlockRing->Outstanding, >, 0);
-    --BlockRing->Outstanding;
-
-    KeReleaseSpinLock(&BlockRing->Lock, Irql);
-}
diff --git a/src/xenvbd/blockring.h b/src/xenvbd/blockring.h
index 4c94b6c..1117d73 100644
--- a/src/xenvbd/blockring.h
+++ b/src/xenvbd/blockring.h
@@ -94,10 +94,4 @@ BlockRingSubmit(
     IN  PXENVBD_REQUEST             Request
     );
 
-extern VOID
-BlockRingAbort(
-    IN  PXENVBD_BLOCKRING           BlockRing,
-    IN  PXENVBD_REQUEST             Request
-    );
-
 #endif // _XENVBD_BLOCKRING_H
diff --git a/src/xenvbd/pdo.c b/src/xenvbd/pdo.c
index 198c4d3..2971e12 100644
--- a/src/xenvbd/pdo.c
+++ b/src/xenvbd/pdo.c
@@ -1721,8 +1721,7 @@ PdoPreResume(
     )
 {
     LIST_ENTRY          List;
-    PXENVBD_BLOCKRING   BlockRing = FrontendGetBlockRing(Pdo->Frontend);
-    
+
     InitializeListHead(&List);
 
     // pop all submitted requests, cleanup and add associated SRB to a list
@@ -1735,7 +1734,6 @@ PdoPreResume(
         Request = CONTAINING_RECORD(Entry, XENVBD_REQUEST, Entry);
         SrbExt = GetSrbExt(Request->Srb);
 
-        BlockRingAbort(BlockRing, Request);
         RequestCleanup(Pdo, Request);
         __LookasideFree(&Pdo->RequestList, Request);
 
-- 
2.39.5