MdeModulePkg ScsiDiskDxe: Raise the Tpl of async IO callback to TPL_NOTIFY

When reading data from non-blockingly from a CD-ROM logic partition, the
procedure can be shown by the following call stack:
(The write process is similar)

|-------------------|
| DiskIoDxe (logic) |<---Raise Tpl to TPL_CALLBACK
|-------------------|
 |
 | Sub-task 1 (UnderRun) succeeds
 |
 |    |-----------------|     |-----------------|     |-----------------|
 +--->|  PartitionDxe   |---->| DiskIoDxe (Phy) |---->|   ScsiDiskDxe   |
 |    |-----------------|     |-----------------|     |-----------------|
 |
 | Sub-task 2 (OverRun) fails
 |
 |    |-----------------|     |-----------------|     |-----------------|
 +--->|  PartitionDxe   |---->| DiskIoDxe (Phy) |---->|   ScsiDiskDxe   |
 |    |-----------------|     |-----------------|     |-----------------|
 |                                     ^
 |                                     |
 More subtasks...              Wait indefinitely
 |
 |<---Restore Tpl
 |
 Completes

In PartitionDxe, if the 'Lba' and 'BufferSize' parameters passed to
function PartitionReadBlocksEx() are invalid, the function will issue a
blocking ReadDisk call (in function ProbeMediaStatusEx()).

In DiskIoDxe, blocking I/O request will wait for all the non-blocking I/O
requests to complete first before sending down the blocking request.

If the Tpl of the async I/O callback in ScsiDiskDxe is TPL_CALLBACK and
Sub-task 1 (UnderRun) succeeds but Sub-task 2 (OverRun) fails with an
invalid parameter, DiskIoDxe will wait indefinitely for the event created
by ScsiDiskDxe of Sub-task 1 to signal.

Hence, this commit will raise the Tpl of async IO callback in ScsiDiskDxe
to TPL_NOTIFY so that the indefinite wait in DiskIoDxe can be avoided.

(Sync patch r19452 from main trunk.)

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/branches/UDK2015@19473 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 7 insertions, 1 deletions

diff --git a/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.h b/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.h
index 7a287d3bb3..2406df51b8 100644
--- a/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.h
+++ b/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.h
@@ -98,7 +98,13 @@ typedef struct {
 typedef struct {

   EFI_BLOCK_IO2_TOKEN                  *Token;

   //

-  // The queue for Scsi Read/Write requests of a BlockIo2

+  // The flag indicates if the last Scsi Read/Write sub-task for a BlockIo2

+  // request is sent to device

+  //

+  BOOLEAN                              LastScsiRW;

+

+  //

+  // The queue for Scsi Read/Write sub-tasks of a BlockIo2 request

   //

   LIST_ENTRY                           ScsiRWQueue;