[win-pv-devel] [PATCH] Improve auditing in CACHE and GNTTAB interfaces

[Paul Durrant <pdurrant@xxxxxxxxx>]

Add 'Get' and 'Put' counters to CACHEs which can then be checked for
equality at destruction time to make sure all objects have been returned.
Also add a list of GNTTAB caches so that the code can BUG on any
outstanding caches at Release.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
 src/xenbus/cache.c  | 31 ++++++++++++++++++++++---------
 src/xenbus/gnttab.c | 21 ++++++++++++++++++++-
 2 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/src/xenbus/cache.c b/src/xenbus/cache.c
index ba7dcdf..83993ca 100644
--- a/src/xenbus/cache.c
+++ b/src/xenbus/cache.c
@@ -79,8 +79,10 @@ struct _XENBUS_CACHE {
     VOID                    (*ReleaseLock)(PVOID);
     PVOID                   Argument;
     LIST_ENTRY              GetList;
+    LONG                    GetCount;
     PLIST_ENTRY             PutList;
-    LONG                    ObjectCount;
+    LONG                    PutCount;
+    LONG                    ListCount;
     PXENBUS_CACHE_MAGAZINE  Magazine;
     ULONG                   MagazineCount;
     XENBUS_CACHE_FIST       FIST;
@@ -225,7 +227,7 @@ CacheGetObjectFromList(
     KIRQL                       Irql = PASSIVE_LEVEL;
     NTSTATUS                    status;
 
-    Count = InterlockedDecrement(&Cache->ObjectCount);
+    Count = InterlockedDecrement(&Cache->ListCount);
 
     status = STATUS_NO_MEMORY;
     if (Count < 0)
@@ -255,7 +257,7 @@ CacheGetObjectFromList(
     return Object;
 
 fail1:
-    (VOID) InterlockedIncrement(&Cache->ObjectCount);
+    (VOID) InterlockedIncrement(&Cache->ListCount);
 
     return NULL;    
 }
@@ -294,7 +296,7 @@ CachePutObjectToList(
 
     KeMemoryBarrier();
 
-    (VOID) InterlockedIncrement(&Cache->ObjectCount);
+    (VOID) InterlockedIncrement(&Cache->ListCount);
 }
 
 static PVOID
@@ -305,6 +307,7 @@ CacheGetObjectFromMagazine(
 {
     PXENBUS_CACHE_MAGAZINE  Magazine;
 
+    ASSERT3U(Index, <, Cache->MagazineCount);
     Magazine = &Cache->Magazine[Index];
 
     for (Index = 0; Index < XENBUS_CACHE_MAGAZINE_SLOTS; Index++) {
@@ -330,6 +333,7 @@ CachePutObjectToMagazine(
 {
     PXENBUS_CACHE_MAGAZINE  Magazine;
 
+    ASSERT3U(Index, <, Cache->MagazineCount);
     Magazine = &Cache->Magazine[Index];
 
     for (Index = 0; Index < XENBUS_CACHE_MAGAZINE_SLOTS; Index++) {
@@ -385,6 +389,8 @@ CacheGet(
 done:
     KeLowerIrql(Irql);
 
+    (VOID) InterlockedIncrement(&Cache->GetCount);
+
     return Object;
 }
 
@@ -401,6 +407,8 @@ CachePut(
 
     UNREFERENCED_PARAMETER(Interface);
 
+    (VOID) InterlockedIncrement(&Cache->PutCount);
+
     KeRaiseIrql(DISPATCH_LEVEL, &Irql);
     Index = KeGetCurrentProcessorNumberEx(NULL);
 
@@ -679,17 +687,22 @@ CacheDestroy(
 
     RtlZeroMemory(&Cache->ListEntry, sizeof (LIST_ENTRY));
 
+    ASSERT3U(Cache->PutCount, ==, Cache->GetCount);
+    Cache->PutCount = 0;
+    Cache->GetCount = 0;
+
     Cache->Reservation = 0;
     CacheFlushMagazines(Cache);
-    CacheSpill(Cache, Cache->ObjectCount);
-
-    ASSERT3U(Cache->ObjectCount, ==, 0);
 
     ASSERT(IsZeroMemory(Cache->Magazine, sizeof (XENBUS_CACHE_MAGAZINE) * 
Cache->MagazineCount));
     __CacheFree(Cache->Magazine);
     Cache->Magazine = NULL;
     Cache->MagazineCount = 0;
 
+    CacheSpill(Cache, Cache->ListCount);
+    ASSERT3U(Cache->ListCount, ==, 0);
+
+    ASSERT(IsListEmpty(&Cache->GetList));
     RtlZeroMemory(&Cache->GetList, sizeof (LIST_ENTRY));
 
     RtlZeroMemory(&Cache->FIST, sizeof (XENBUS_CACHE_FIST));
@@ -737,7 +750,7 @@ CacheDebugCallback(
                          &Context->DebugInterface,
                          "- %s: Count = %d (Reservation = %d)\n",
                          Cache->Name,
-                         Cache->ObjectCount,
+                         Cache->ListCount,
                          Cache->Reservation);
         }
     }
@@ -793,7 +806,7 @@ CacheMonitor(
 
             Cache = CONTAINING_RECORD(ListEntry, XENBUS_CACHE, ListEntry);
 
-            Count = Cache->ObjectCount;
+            Count = Cache->ListCount;
 
             if (Count < Cache->Reservation)
                 CacheFill(Cache, Cache->Reservation - Count);
diff --git a/src/xenbus/gnttab.c b/src/xenbus/gnttab.c
index 3912028..165e38f 100644
--- a/src/xenbus/gnttab.c
+++ b/src/xenbus/gnttab.c
@@ -53,8 +53,9 @@
 #define MAXNAMELEN  128
 
 struct _XENBUS_GNTTAB_CACHE {
-    PXENBUS_GNTTAB_CONTEXT  Context;
+    LIST_ENTRY              ListEntry;
     CHAR                    Name[MAXNAMELEN];
+    PXENBUS_GNTTAB_CONTEXT  Context;
     VOID                    (*AcquireLock)(PVOID);
     VOID                    (*ReleaseLock)(PVOID);
     PVOID                   Argument;
@@ -81,6 +82,7 @@ struct _XENBUS_GNTTAB_CONTEXT {
     PXENBUS_SUSPEND_CALLBACK    SuspendCallbackEarly;
     XENBUS_DEBUG_INTERFACE      DebugInterface;
     PXENBUS_DEBUG_CALLBACK      DebugCallback;
+    LIST_ENTRY                  List;
 };
 
 #define XENBUS_GNTTAB_TAG   'TTNG'
@@ -321,6 +323,7 @@ GnttabCreateCache(
     )
 {
     PXENBUS_GNTTAB_CONTEXT      Context = Interface->Context;
+    KIRQL                       Irql;
     NTSTATUS                    status;
 
     *Cache = __GnttabAllocate(sizeof (XENBUS_GNTTAB_CACHE));
@@ -356,6 +359,10 @@ GnttabCreateCache(
     if (!NT_SUCCESS(status))
         goto fail3;
 
+    KeAcquireSpinLock(&Context->Lock, &Irql);
+    InsertTailList(&Context->List, &(*Cache)->ListEntry);
+    KeReleaseSpinLock(&Context->Lock, Irql);
+
     return STATUS_SUCCESS;
 
 fail3:
@@ -388,6 +395,13 @@ GnttabDestroyCache(
     )
 {
     PXENBUS_GNTTAB_CONTEXT      Context = Interface->Context;
+    KIRQL                       Irql;
+
+    KeAcquireSpinLock(&Context->Lock, &Irql);
+    RemoveEntryList(&Cache->ListEntry);
+    KeReleaseSpinLock(&Context->Lock, Irql);
+
+    RtlZeroMemory(&Cache->ListEntry, sizeof (LIST_ENTRY));
 
     XENBUS_CACHE(Destroy,
                  &Context->CacheInterface,
@@ -717,6 +731,9 @@ GnttabRelease(
 
     Trace("====>\n");
 
+    if (!IsListEmpty(&Context->List))
+        BUG("OUTSTANDING CACHES");
+
     XENBUS_DEBUG(Deregister,
                  &Context->DebugInterface,
                  Context->DebugCallback);
@@ -816,6 +833,7 @@ GnttabInitialize(
     ASSERT(NT_SUCCESS(status));
     ASSERT((*Context)->DebugInterface.Interface.Context != NULL);
 
+    InitializeListHead(&(*Context)->List);
     KeInitializeSpinLock(&(*Context)->Lock);
 
     (*Context)->Fdo = Fdo;
@@ -878,6 +896,7 @@ GnttabTeardown(
     Context->Fdo = NULL;
 
     RtlZeroMemory(&Context->Lock, sizeof (KSPIN_LOCK));
+    RtlZeroMemory(&Context->List, sizeof (LIST_ENTRY));
 
     RtlZeroMemory(&Context->DebugInterface,
                   sizeof (XENBUS_DEBUG_INTERFACE));
-- 
2.1.1


_______________________________________________
win-pv-devel mailing list
win-pv-devel@xxxxxxxxxxxxxxxxxxxx
http://lists.xenproject.org/cgi-bin/mailman/listinfo/win-pv-devel