01/02: [NTOSKRNL] Stubplement CcPinMappedData() and simplify CcPinRead()

[Pierre Schweitzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=469e15c7ae5d2b7dc266fd...

commit 469e15c7ae5d2b7dc266fdde7beb173d8263d563
Author:     Pierre Schweitzer [e-mail]
AuthorDate: Sun Aug 26 21:49:05 2018 +0200
Commit:     Pierre Schweitzer [e-mail]
CommitDate: Sun Aug 26 22:05:11 2018 +0200

[NTOSKRNL] Stubplement CcPinMappedData() and simplify CcPinRead()

It's based on the code that was in CcPinRead() implementation. This
    made no sense to have CcPinMappedData() doing nothing while implementing
    everything in CcPinRead(). Indeed, drivers (starting with MS drivers)
    can map data first and pin it afterwards with CcPinMappedData(). It was
    leading to incorrect behavior with our previous noop implementation.
---
 ntoskrnl/cc/pin.c | 53 +++++++++++++++++++++++++++--------------------------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/ntoskrnl/cc/pin.c b/ntoskrnl/cc/pin.c
index 2d48a27a0a..8b99b8c210 100644
--- a/ntoskrnl/cc/pin.c
+++ b/ntoskrnl/cc/pin.c
@@ -161,6 +161,7 @@ CcPinMappedData (
     IN	ULONG Flags,
     OUT	PVOID * Bcb)
 {
+    PINTERNAL_BCB iBcb;
     PROS_SHARED_CACHE_MAP SharedCacheMap;

CCTRACE(CC_API_DEBUG, "FileOffset=%p FileOffset=%p Length=%lu Flags=0x%lx\n",
@@ -174,7 +175,21 @@ CcPinMappedData (
     ASSERT(SharedCacheMap);
     ASSERT(SharedCacheMap->PinAccess);

-    /* no-op for current implementation. */
+    iBcb = *Bcb;
+    ASSERT(iBcb->Pinned == FALSE);
+
+    iBcb->Pinned = TRUE;
+    iBcb->Vacb->PinCount++;
+
+    if (Flags & PIN_EXCLUSIVE)
+    {
+        ExAcquireResourceExclusiveLite(&iBcb->Lock, TRUE);
+    }
+    else
+    {
+        ExAcquireResourceSharedLite(&iBcb->Lock, TRUE);
+    }
+
     return TRUE;
 }

@@ -191,8 +206,6 @@ CcPinRead (
     OUT	PVOID * Bcb,
     OUT	PVOID * Buffer)
 {
-    PINTERNAL_BCB iBcb;
-
     CCTRACE(CC_API_DEBUG, "FileOffset=%p FileOffset=%p Length=%lu Flags=0x%lx\n",
         FileObject, FileOffset, Length, Flags);

@@ -205,32 +218,20 @@ CcPinRead (
         ++CcPinReadNoWait;
     }

-    if (CcMapData(FileObject, FileOffset, Length, Flags, Bcb, Buffer))
+    /* Map first */
+    if (!CcMapData(FileObject, FileOffset, Length, Flags, Bcb, Buffer))
     {
-        if (CcPinMappedData(FileObject, FileOffset, Length, Flags, Bcb))
-        {
-            iBcb = *Bcb;
-
-            ASSERT(iBcb->Pinned == FALSE);
-
-            iBcb->Pinned = TRUE;
-            iBcb->Vacb->PinCount++;
-
-            if (Flags & PIN_EXCLUSIVE)
-            {
-                ExAcquireResourceExclusiveLite(&iBcb->Lock, TRUE);
-            }
-            else
-            {
-                ExAcquireResourceSharedLite(&iBcb->Lock, TRUE);
-            }
+        return FALSE;
+    }

-            return TRUE;
-        }
-        else
-            CcUnpinData(*Bcb);
+    /* Pin then */
+    if (!CcPinMappedData(FileObject, FileOffset, Length, Flags, Bcb))
+    {
+        CcUnpinData(*Bcb);
+        return FALSE;
     }
-    return FALSE;
+
+    return TRUE;
 }

/*