[PATCH xenbus] Re-work ASSERTion to avoid issues with VERIFIER list checks

[Paul Durrant <paul@xxxxxxx>]

From: Paul Durrant <pdurrant@xxxxxxxxxx>

The current mechanism of ASSERTing that there is a single item on the list
seems to fail when list checking is turned on in VERIFIER. Avoid going round
the back of the list macros by instead ASSERTing that the list is empty, once
the entry is removed.

Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
---
 src/xenbus/cache.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/xenbus/cache.c b/src/xenbus/cache.c
index ba0177b71223..48772d419fd0 100644
--- a/src/xenbus/cache.c
+++ b/src/xenbus/cache.c
@@ -385,14 +385,14 @@ CacheDestroySlab(
     // The only reason the cursor should be pointing at this slab is
     // if it is the only one in the list.
     //
-    if (Cache->Cursor == &Slab->ListEntry) {
-        ASSERT(Slab->ListEntry.Flink == &Cache->SlabList);
-        ASSERT(Slab->ListEntry.Blink == &Cache->SlabList);
+    if (Cache->Cursor == &Slab->ListEntry)
         Cache->Cursor = &Cache->SlabList;
-    }
 
     RemoveEntryList(&Slab->ListEntry);
 
+    ASSERT(Cache->Cursor != &Cache->SlabList ||
+           IsListEmpty(&Cache->SlabList));
+
     Index = Slab->MaximumOccupancy;
     while (--Index >= 0) {
         PVOID Object = (PVOID)&Slab->Buffer[Index * Cache->Size];
-- 
2.17.1