From 258329b01b77d2cecce205bc270e63375df20822 Mon Sep 17 00:00:00 2001
From: Art Yerkes <art.yerkes@gmail.com>
Date: Mon, 28 Jul 2008 12:38:47 +0000
Subject: [PATCH] Fix (among other things) failure to boot when a CD is not
 inserted, caused by the new (correct) ASSERT in mutex acquisition in
 MmProbeAndLockPages, which was erroneously being called from
 IoBuildAsynchronousFsdRequest at DISPATCH_LEVEL.

The only correct course of action when calling IoBuildAsynchronousFsdRequest
at DISPATCH_LEVEL is to MmBuildMdlForNonPagedPool since the buffer must be
nonpaged (if the IRP completes synchronously, we'll still be at DISPATCH_LEVEL)
This is the case when direct io is done at DISPATCH_LEVEL using
IoBuildAsynchronousFsdRequest.

svn path=/trunk/; revision=34899
---
 reactos/drivers/storage/scsiport/scsiport.c |  3 +-
 reactos/ntoskrnl/io/iomgr/irp.c             | 43 ++++++++++++---------
 2 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/reactos/drivers/storage/scsiport/scsiport.c b/reactos/drivers/storage/scsiport/scsiport.c
index e7296e36c06..2f63cb5ee16 100644
--- a/reactos/drivers/storage/scsiport/scsiport.c
+++ b/reactos/drivers/storage/scsiport/scsiport.c
@@ -4405,7 +4405,8 @@ SpiCompletionRoutine(PDEVICE_OBJECT DeviceObject,
 
     if (Irp->MdlAddress != NULL)
     {
-        MmUnlockPages(Irp->MdlAddress);
+		/* We don't need to unlock this MDL because the request could 
+		 * only have come from dispatch level */
         IoFreeMdl(Irp->MdlAddress);
         Irp->MdlAddress = NULL;
     }
diff --git a/reactos/ntoskrnl/io/iomgr/irp.c b/reactos/ntoskrnl/io/iomgr/irp.c
index fdb48064786..f4f7ea4a3de 100644
--- a/reactos/ntoskrnl/io/iomgr/irp.c
+++ b/reactos/ntoskrnl/io/iomgr/irp.c
@@ -682,23 +682,30 @@ IoBuildAsynchronousFsdRequest(IN ULONG MajorFunction,
                 return NULL;
             }
 
-            /* Probe and Lock */
-            _SEH_TRY
-            {
-                /* Do the probe */
-                MmProbeAndLockPages(Irp->MdlAddress,
-                                    KernelMode,
-                                    MajorFunction == IRP_MJ_READ ?
-                                    IoWriteAccess : IoReadAccess);
-            }
-            _SEH_HANDLE
-            {
-                /* Free the IRP and its MDL */
-                IoFreeMdl(Irp->MdlAddress);
-                IoFreeIrp(Irp);
-                Irp = NULL;
-            }
-            _SEH_END;
+			if (KeGetCurrentIrql() >= DISPATCH_LEVEL)
+			{
+				MmBuildMdlForNonPagedPool(Irp->MdlAddress);
+			}
+			else
+			{
+				/* Probe and Lock */
+				_SEH_TRY
+				{
+					/* Do the probe */
+					MmProbeAndLockPages(Irp->MdlAddress,
+										KernelMode,
+										MajorFunction == IRP_MJ_READ ?
+										IoWriteAccess : IoReadAccess);
+				}
+				_SEH_HANDLE
+				{
+					/* Free the IRP and its MDL */
+					IoFreeMdl(Irp->MdlAddress);
+					IoFreeIrp(Irp);
+					Irp = NULL;
+				}
+				_SEH_END;
+			}
 
             /* This is how we know if we failed during the probe */
             if (!Irp) return NULL;
@@ -1344,7 +1351,7 @@ IofCompleteRequest(IN PIRP Irp,
     Mdl = Irp->MdlAddress;
     while (Mdl)
     {
-        MmUnlockPages(Mdl);
+		MmUnlockPages(Mdl);
         Mdl = Mdl->Next;
     }