From a0cb134bd3ad1894096fc6894ce0731146b5b7b5 Mon Sep 17 00:00:00 2001
From: Bill Zissimopoulos <billziss@navimatics.com>
Date: Wed, 9 Nov 2016 15:58:17 -0800
Subject: [PATCH] sys: FspFsvolReadNonCached,FspFsvolWriteNonCached: reuse work
 Requests

---
 src/sys/read.c  | 26 ++++++++++++++++++--------
 src/sys/write.c | 27 +++++++++++++++++++--------
 2 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/src/sys/read.c b/src/sys/read.c
index 1a9f0bd4..e9248652 100644
--- a/src/sys/read.c
+++ b/src/sys/read.c
@@ -266,15 +266,25 @@ static NTSTATUS FspFsvolReadNonCached(
     /* convert FileNode to shared */
     FspFileNodeConvertExclusiveToShared(FileNode, Full);
 
-    /* delete any work item if present! */
-    FspIrpDeleteRequest(Irp);
-
-    /* create request */
-    Result = FspIopCreateRequestEx(Irp, 0, 0, FspFsvolReadNonCachedRequestFini, &Request);
-    if (!NT_SUCCESS(Result))
+    Request = FspIrpRequest(Irp);
+    if (0 == Request)
     {
-        FspFileNodeRelease(FileNode, Full);
-        return Result;
+        /* create request */
+        Result = FspIopCreateRequestEx(Irp, 0, 0, FspFsvolReadNonCachedRequestFini, &Request);
+        if (!NT_SUCCESS(Result))
+        {
+            FspFileNodeRelease(FileNode, Full);
+            return Result;
+        }
+    }
+    else
+    {
+        /* reuse existing request */
+        ASSERT(Request->Size == sizeof *Request);
+        ASSERT(Request->Hint == (UINT_PTR)Irp);
+        FspIopResetRequest(Request, FspFsvolReadNonCachedRequestFini);
+        RtlZeroMemory(&Request->Req,
+            sizeof *Request - FIELD_OFFSET(FSP_FSCTL_TRANSACT_REQ, Req));
     }
 
     Request->Kind = FspFsctlTransactReadKind;
diff --git a/src/sys/write.c b/src/sys/write.c
index 9f141da3..ea2a5a7e 100644
--- a/src/sys/write.c
+++ b/src/sys/write.c
@@ -333,16 +333,27 @@ static NTSTATUS FspFsvolWriteNonCached(
         }
     }
 
-    /* delete any work item if present! */
-    FspIrpDeleteRequest(Irp);
-
-    /* create request */
-    Result = FspIopCreateRequestEx(Irp, 0, 0, FspFsvolWriteNonCachedRequestFini, &Request);
-    if (!NT_SUCCESS(Result))
+    Request = FspIrpRequest(Irp);
+    if (0 == Request)
     {
-        FspFileNodeRelease(FileNode, Full);
-        return Result;
+        /* create request */
+        Result = FspIopCreateRequestEx(Irp, 0, 0, FspFsvolWriteNonCachedRequestFini, &Request);
+        if (!NT_SUCCESS(Result))
+        {
+            FspFileNodeRelease(FileNode, Full);
+            return Result;
+        }
     }
+    else
+    {
+        /* reuse existing request */
+        ASSERT(Request->Size == sizeof *Request);
+        ASSERT(Request->Hint == (UINT_PTR)Irp);
+        FspIopResetRequest(Request, FspFsvolWriteNonCachedRequestFini);
+        RtlZeroMemory(&Request->Req,
+            sizeof *Request - FIELD_OFFSET(FSP_FSCTL_TRANSACT_REQ, Req));
+    }
+
 
     Request->Kind = FspFsctlTransactWriteKind;
     Request->Req.Write.UserContext = FileNode->UserContext;