[NTOS:CM] Implement the shared lock macro for use

CmpAcquireKcbLockSharedByKey can come in handy for use to lock KCBs by their convkey with a shared lock, specifically we would need this for cache lookup stuff.

ntoskrnl/include/internal/cm_x.h

@@ -89,6 +89,14 @@
     (GET_HASH_ENTRY(CmpCacheTable,                                  \
                     (k)->ConvKey)->Owner == KeGetCurrentThread())
 
+//
+// Shared acquires a KCB by index
+//
+#define CmpAcquireKcbLockSharedByIndex(i)                           \
+{                                                                   \
+    ExAcquirePushLockShared(&CmpCacheTable[(i)].Lock);              \
+}
+
 //
 // Exclusively acquires a KCB by index
 //
@@ -120,6 +128,16 @@ CmpAcquireKcbLockExclusiveByKey(IN ULONG ConvKey)
     CmpAcquireKcbLockExclusiveByIndex(GET_HASH_INDEX(ConvKey));
 }
 
+//
+// Shared acquires a KCB by key
+//
+FORCEINLINE
+VOID
+CmpAcquireKcbLockSharedByKey(
+    _In_ ULONG ConvKey)
+{
+    CmpAcquireKcbLockSharedByIndex(GET_HASH_INDEX(ConvKey));
+}
 
 //
 // Shared acquires a KCB
@@ -130,14 +148,6 @@ CmpAcquireKcbLockExclusiveByKey(IN ULONG ConvKey)
                                             (k)->ConvKey)->Lock);    \
 }
 
-//
-// Shared acquires a KCB by index
-//
-#define CmpAcquireKcbLockSharedByIndex(i)                           \
-{                                                                   \
-    ExAcquirePushLockShared(&CmpCacheTable[(i)].Lock);              \
-}
-
 //
 // Tries to convert a KCB lock
 //