MdeModulePkg/ScsiDisk: Using back-off algorithm to dynamically adjust transfer length in a single SCSI/ATAPI transfer to reach best device compatibility.

Besides this, the patch also fixed:
1) Wrong return value in SenseDataLength field of packet field of EFI_EXT_SCSI_PASS_THRU protocol, it should reflect real sense data length we got.
2) Wrong logic in ScsiDiskRequestSenseKeys that the logic makes SenseData pointer unaligned compared with BlockIo.Media.IoAlign field.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Tian, Feng <feng.tian@intel.com>
Reviewed-by: Zeng, Star <star.zeng@intel.com>
Reviewed-by: Fu, Siyuan <siyuan.fu@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15491 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 143 insertions, 81 deletions

diff --git a/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c b/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c
index 0eb1036e46..e5dd6b9c4d 100644
--- a/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c
+++ b/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c
@@ -1279,40 +1279,46 @@ DetectMediaParsingSenseKeys (
     ScsiDiskDevice->BlkIo.Media->MediaPresent = FALSE;

     ScsiDiskDevice->BlkIo.Media->LastBlock    = 0;

     *Action = ACTION_NO_ACTION;

+    DEBUG ((EFI_D_VERBOSE, "ScsiDisk: ScsiDiskIsNoMedia\n"));

     return EFI_SUCCESS;

   }

 

   if (ScsiDiskIsMediaChange (SenseData, NumberOfSenseKeys)) {

     ScsiDiskDevice->BlkIo.Media->MediaId++;

+    DEBUG ((EFI_D_VERBOSE, "ScsiDisk: ScsiDiskIsMediaChange!\n"));

     return EFI_SUCCESS;

   }

 

   if (ScsiDiskIsResetBefore (SenseData, NumberOfSenseKeys)) {

     *Action = ACTION_RETRY_COMMAND_LATER;

+    DEBUG ((EFI_D_VERBOSE, "ScsiDisk: ScsiDiskIsResetBefore!\n"));

     return EFI_SUCCESS;

   }

 

   if (ScsiDiskIsMediaError (SenseData, NumberOfSenseKeys)) {

-    ScsiDiskDevice->BlkIo.Media->MediaPresent = FALSE;

-    ScsiDiskDevice->BlkIo.Media->LastBlock    = 0;

-    *Action = ACTION_NO_ACTION;

+    DEBUG ((EFI_D_VERBOSE, "ScsiDisk: ScsiDiskIsMediaError\n"));

+    *Action = ACTION_RETRY_WITH_BACKOFF_ALGO;

     return EFI_DEVICE_ERROR;

   }

 

   if (ScsiDiskIsHardwareError (SenseData, NumberOfSenseKeys)) {

-    *Action = ACTION_NO_ACTION;

+    DEBUG ((EFI_D_VERBOSE, "ScsiDisk: ScsiDiskIsHardwareError\n"));

+    *Action = ACTION_RETRY_WITH_BACKOFF_ALGO;

     return EFI_DEVICE_ERROR;

   }

 

   if (!ScsiDiskIsDriveReady (SenseData, NumberOfSenseKeys, &RetryLater)) {

     if (RetryLater) {

       *Action = ACTION_RETRY_COMMAND_LATER;

+      DEBUG ((EFI_D_VERBOSE, "ScsiDisk: ScsiDiskDriveNotReady!\n"));

       return EFI_SUCCESS;

     }

     *Action = ACTION_NO_ACTION;

     return EFI_DEVICE_ERROR;

   }

 

+  *Action = ACTION_RETRY_WITH_BACKOFF_ALGO;

+  DEBUG ((EFI_D_VERBOSE, "ScsiDisk: Sense Key = 0x%x ASC = 0x%x!\n", SenseData->Sense_Key, SenseData->Addnl_Sense_Code));

   return EFI_SUCCESS;

 }

 

@@ -1618,9 +1624,14 @@ ScsiDiskRequestSenseKeys (
 

   *NumberOfSenseKeys  = 0;

   *SenseDataArray     = ScsiDiskDevice->SenseData;

-  PtrSenseData        = ScsiDiskDevice->SenseData;

+  Status              = EFI_SUCCESS;

+  PtrSenseData        = AllocateAlignedBuffer (ScsiDiskDevice, sizeof (EFI_SCSI_SENSE_DATA));

+  if (PtrSenseData == NULL) {

+    return EFI_DEVICE_ERROR;

+  }

 

   for (SenseReq = TRUE; SenseReq;) {

+    ZeroMem (PtrSenseData, sizeof (EFI_SCSI_SENSE_DATA));

     Status = ScsiRequestSenseCommand (

               ScsiDiskDevice->ScsiIo,

               SCSI_DISK_TIMEOUT,

@@ -1651,12 +1662,15 @@ ScsiDiskRequestSenseKeys (
     if (EFI_ERROR (FallStatus)) {

       if (*NumberOfSenseKeys != 0) {

         *NeedRetry = FALSE;

-        return EFI_SUCCESS;

+        Status = EFI_SUCCESS;

+        goto EXIT;

       } else {

-        return EFI_DEVICE_ERROR;

+        Status = EFI_DEVICE_ERROR;

+        goto EXIT;

       }

     }

 

+    CopyMem (ScsiDiskDevice->SenseData + *NumberOfSenseKeys, PtrSenseData, SenseDataLength);

     (*NumberOfSenseKeys) += 1;

 

     //

@@ -1667,9 +1681,11 @@ ScsiDiskRequestSenseKeys (
         (*NumberOfSenseKeys == ScsiDiskDevice->SenseDataNumber)) {

       SenseReq = FALSE;

     }

-    PtrSenseData += 1;

   }

-  return EFI_SUCCESS;

+

+EXIT:

+  FreeAlignedBuffer (PtrSenseData, sizeof (EFI_SCSI_SENSE_DATA));

+  return Status;

 }

 

 

@@ -1780,11 +1796,6 @@ ScsiDiskReadSectors (
   UINT8               Index;

   UINT8               MaxRetry;

   BOOLEAN             NeedRetry;

-  EFI_SCSI_SENSE_DATA *SenseData;

-  UINTN               NumberOfSenseKeys;

-

-  SenseData         = NULL;

-  NumberOfSenseKeys = 0;

 

   Status            = EFI_SUCCESS;

 

@@ -1855,8 +1866,6 @@ ScsiDiskReadSectors (
         Status = ScsiDiskRead10 (

                   ScsiDiskDevice,

                   &NeedRetry,

-                  &SenseData,

-                  &NumberOfSenseKeys,

                   Timeout,

                   PtrBuffer,

                   &ByteCount,

@@ -1867,8 +1876,6 @@ ScsiDiskReadSectors (
         Status = ScsiDiskRead16 (

                   ScsiDiskDevice,

                   &NeedRetry,

-                  &SenseData,

-                  &NumberOfSenseKeys,

                   Timeout,

                   PtrBuffer,

                   &ByteCount,

@@ -1934,11 +1941,6 @@ ScsiDiskWriteSectors (
   UINT8               Index;

   UINT8               MaxRetry;

   BOOLEAN             NeedRetry;

-  EFI_SCSI_SENSE_DATA *SenseData;

-  UINTN               NumberOfSenseKeys;

-

-  SenseData         = NULL;

-  NumberOfSenseKeys = 0;

 

   Status            = EFI_SUCCESS;

 

@@ -2008,8 +2010,6 @@ ScsiDiskWriteSectors (
         Status = ScsiDiskWrite10 (

                   ScsiDiskDevice,

                   &NeedRetry,

-                  &SenseData,

-                  &NumberOfSenseKeys,

                   Timeout,

                   PtrBuffer,

                   &ByteCount,

@@ -2020,8 +2020,6 @@ ScsiDiskWriteSectors (
         Status = ScsiDiskWrite16 (

                   ScsiDiskDevice,

                   &NeedRetry,

-                  &SenseData,

-                  &NumberOfSenseKeys,

                   Timeout,

                   PtrBuffer,

                   &ByteCount,

@@ -2060,13 +2058,11 @@ ScsiDiskWriteSectors (
 

   @param  ScsiDiskDevice     The pointer of ScsiDiskDevice

   @param  NeedRetry          The pointer of flag indicates if needs retry if error happens

-  @param  SenseDataArray     NOT used yet in this function

-  @param  NumberOfSenseKeys  The number of sense key

   @param  Timeout            The time to complete the command

   @param  DataBuffer         The buffer to fill with the read out data

   @param  DataLength         The length of buffer

   @param  StartLba           The start logic block address

-  @param  SectorSize         The size of sector

+  @param  SectorCount        The number of blocks to read

 

   @return  EFI_STATUS is returned by calling ScsiRead10Command().

 **/

@@ -2074,13 +2070,11 @@ EFI_STATUS
 ScsiDiskRead10 (

   IN     SCSI_DISK_DEV         *ScsiDiskDevice,

      OUT BOOLEAN               *NeedRetry,

-     OUT EFI_SCSI_SENSE_DATA   **SenseDataArray,   OPTIONAL

-     OUT UINTN                 *NumberOfSenseKeys,

   IN     UINT64                Timeout,

      OUT UINT8                 *DataBuffer,

   IN OUT UINT32                *DataLength,

   IN     UINT32                StartLba,

-  IN     UINT32                SectorSize

+  IN     UINT32                SectorCount

   )

 {

   UINT8       SenseDataLength;

@@ -2090,8 +2084,16 @@ ScsiDiskRead10 (
   UINT8       TargetStatus;

   UINTN       Action;

 

+  //

+  // Implement a backoff algorithem to resolve some compatibility issues that

+  // some SCSI targets or ATAPI devices couldn't correctly response reading/writing

+  // big data in a single operation.

+  // This algorithem will at first try to execute original request. If the request fails

+  // with media error sense data or else, it will reduce the transfer length to half and

+  // try again till the operation succeeds or fails with one sector transfer length.

+  //

+BackOff:

   *NeedRetry          = FALSE;

-  *NumberOfSenseKeys  = 0;

   Action              = ACTION_NO_ACTION;

   SenseDataLength     = (UINT8) (ScsiDiskDevice->SenseDataNumber * sizeof (EFI_SCSI_SENSE_DATA));

   ReturnStatus = ScsiRead10Command (

@@ -2104,7 +2106,7 @@ ScsiDiskRead10 (
                    DataBuffer,

                    DataLength,

                    StartLba,

-                   SectorSize

+                   SectorCount

                    );

 

   if (ReturnStatus == EFI_NOT_READY) {

@@ -2145,14 +2147,26 @@ ScsiDiskRead10 (
     return EFI_DEVICE_ERROR;

   }

 

-  if (TargetStatus == EFI_EXT_SCSI_STATUS_TARGET_CHECK_CONDITION) {

-    DEBUG ((EFI_D_VERBOSE, "ScsiDiskRead10: Check Condition happened!\n"));

+  if ((TargetStatus == EFI_EXT_SCSI_STATUS_TARGET_CHECK_CONDITION) || (EFI_ERROR (ReturnStatus))) {

+    DEBUG ((EFI_D_ERROR, "ScsiDiskRead10: Check Condition happened!\n"));

     Status = DetectMediaParsingSenseKeys (ScsiDiskDevice, ScsiDiskDevice->SenseData, SenseDataLength / sizeof (EFI_SCSI_SENSE_DATA), &Action);

-    if (EFI_ERROR (Status)) {

-      return Status;

-    } else if (Action == ACTION_RETRY_COMMAND_LATER) {

+    if (Action == ACTION_RETRY_COMMAND_LATER) {

       *NeedRetry = TRUE;

       return EFI_DEVICE_ERROR;

+    } else if (Action == ACTION_RETRY_WITH_BACKOFF_ALGO) {

+      if (SectorCount <= 1) {

+        //

+        // Jump out if the operation still fails with one sector transfer length.

+        //

+        *NeedRetry = FALSE;

+        return EFI_DEVICE_ERROR;

+      }

+      //

+      // Try again with half length if the sense data shows we need to retry.

+      //

+      SectorCount >>= 1;

+      *DataLength = SectorCount * ScsiDiskDevice->BlkIo.Media->BlockSize;

+      goto BackOff;

     } else {

       *NeedRetry = FALSE;

       return EFI_DEVICE_ERROR;

@@ -2168,13 +2182,11 @@ ScsiDiskRead10 (
 

   @param  ScsiDiskDevice     The pointer of ScsiDiskDevice

   @param  NeedRetry          The pointer of flag indicates if needs retry if error happens

-  @param  SenseDataArray     NOT used yet in this function

-  @param  NumberOfSenseKeys  The number of sense key

   @param  Timeout            The time to complete the command

   @param  DataBuffer         The buffer to fill with the read out data

   @param  DataLength         The length of buffer

   @param  StartLba           The start logic block address

-  @param  SectorSize         The size of sector

+  @param  SectorCount        The number of blocks to write

 

   @return  EFI_STATUS is returned by calling ScsiWrite10Command().

 

@@ -2183,13 +2195,11 @@ EFI_STATUS
 ScsiDiskWrite10 (

   IN     SCSI_DISK_DEV         *ScsiDiskDevice,

      OUT BOOLEAN               *NeedRetry,

-     OUT EFI_SCSI_SENSE_DATA   **SenseDataArray,   OPTIONAL

-     OUT UINTN                 *NumberOfSenseKeys,

   IN     UINT64                Timeout,

   IN     UINT8                 *DataBuffer,

   IN OUT UINT32                *DataLength,

   IN     UINT32                StartLba,

-  IN     UINT32                SectorSize

+  IN     UINT32                SectorCount

   )

 {

   EFI_STATUS  Status;

@@ -2199,8 +2209,16 @@ ScsiDiskWrite10 (
   UINT8       TargetStatus;

   UINTN       Action;

 

+  //

+  // Implement a backoff algorithem to resolve some compatibility issues that

+  // some SCSI targets or ATAPI devices couldn't correctly response reading/writing

+  // big data in a single operation.

+  // This algorithem will at first try to execute original request. If the request fails

+  // with media error sense data or else, it will reduce the transfer length to half and

+  // try again till the operation succeeds or fails with one sector transfer length.

+  //

+BackOff:

   *NeedRetry          = FALSE;

-  *NumberOfSenseKeys  = 0;

   Action              = ACTION_NO_ACTION;

   SenseDataLength     = (UINT8) (ScsiDiskDevice->SenseDataNumber * sizeof (EFI_SCSI_SENSE_DATA));

   ReturnStatus = ScsiWrite10Command (

@@ -2213,7 +2231,7 @@ ScsiDiskWrite10 (
                    DataBuffer,

                    DataLength,

                    StartLba,

-                   SectorSize

+                   SectorCount

                    );

   if (ReturnStatus == EFI_NOT_READY) {

     *NeedRetry = TRUE;

@@ -2253,14 +2271,26 @@ ScsiDiskWrite10 (
     return EFI_DEVICE_ERROR;

   }

 

-  if (TargetStatus == EFI_EXT_SCSI_STATUS_TARGET_CHECK_CONDITION) {

-    DEBUG ((EFI_D_VERBOSE, "ScsiDiskWrite10: Check Condition happened!\n"));

+  if ((TargetStatus == EFI_EXT_SCSI_STATUS_TARGET_CHECK_CONDITION) || (EFI_ERROR (ReturnStatus))) {

+    DEBUG ((EFI_D_ERROR, "ScsiDiskWrite10: Check Condition happened!\n"));

     Status = DetectMediaParsingSenseKeys (ScsiDiskDevice, ScsiDiskDevice->SenseData, SenseDataLength / sizeof (EFI_SCSI_SENSE_DATA), &Action);

-    if (EFI_ERROR (Status)) {

-      return Status;

-    } else if (Action == ACTION_RETRY_COMMAND_LATER) {

+    if (Action == ACTION_RETRY_COMMAND_LATER) {

       *NeedRetry = TRUE;

       return EFI_DEVICE_ERROR;

+    } else if (Action == ACTION_RETRY_WITH_BACKOFF_ALGO) {

+      if (SectorCount <= 1) {

+        //

+        // Jump out if the operation still fails with one sector transfer length.

+        //

+        *NeedRetry = FALSE;

+        return EFI_DEVICE_ERROR;

+      }

+      //

+      // Try again with half length if the sense data shows we need to retry.

+      //

+      SectorCount >>= 1;

+      *DataLength = SectorCount * ScsiDiskDevice->BlkIo.Media->BlockSize;

+      goto BackOff;

     } else {

       *NeedRetry = FALSE;

       return EFI_DEVICE_ERROR;

@@ -2276,27 +2306,23 @@ ScsiDiskWrite10 (
 

   @param  ScsiDiskDevice     The pointer of ScsiDiskDevice

   @param  NeedRetry          The pointer of flag indicates if needs retry if error happens

-  @param  SenseDataArray     NOT used yet in this function

-  @param  NumberOfSenseKeys  The number of sense key

   @param  Timeout            The time to complete the command

   @param  DataBuffer         The buffer to fill with the read out data

   @param  DataLength         The length of buffer

   @param  StartLba           The start logic block address

-  @param  SectorSize         The size of sector

+  @param  SectorCount        The number of blocks to read

 

-  @return  EFI_STATUS is returned by calling ScsiRead10Command().

+  @return  EFI_STATUS is returned by calling ScsiRead16Command().

 **/

 EFI_STATUS

 ScsiDiskRead16 (

   IN     SCSI_DISK_DEV         *ScsiDiskDevice,

      OUT BOOLEAN               *NeedRetry,

-     OUT EFI_SCSI_SENSE_DATA   **SenseDataArray,   OPTIONAL

-     OUT UINTN                 *NumberOfSenseKeys,

   IN     UINT64                Timeout,

      OUT UINT8                 *DataBuffer,

   IN OUT UINT32                *DataLength,

   IN     UINT64                StartLba,

-  IN     UINT32                SectorSize

+  IN     UINT32                SectorCount

   )

 {

   UINT8       SenseDataLength;

@@ -2306,8 +2332,16 @@ ScsiDiskRead16 (
   UINT8       TargetStatus;

   UINTN       Action;

 

+  //

+  // Implement a backoff algorithem to resolve some compatibility issues that

+  // some SCSI targets or ATAPI devices couldn't correctly response reading/writing

+  // big data in a single operation.

+  // This algorithem will at first try to execute original request. If the request fails

+  // with media error sense data or else, it will reduce the transfer length to half and

+  // try again till the operation succeeds or fails with one sector transfer length.

+  //

+BackOff:

   *NeedRetry          = FALSE;

-  *NumberOfSenseKeys  = 0;

   Action              = ACTION_NO_ACTION;

   SenseDataLength     = (UINT8) (ScsiDiskDevice->SenseDataNumber * sizeof (EFI_SCSI_SENSE_DATA));

   ReturnStatus = ScsiRead16Command (

@@ -2320,7 +2354,7 @@ ScsiDiskRead16 (
                    DataBuffer,

                    DataLength,

                    StartLba,

-                   SectorSize

+                   SectorCount

                    );

   if (ReturnStatus == EFI_NOT_READY) {

     *NeedRetry = TRUE;

@@ -2360,14 +2394,26 @@ ScsiDiskRead16 (
     return EFI_DEVICE_ERROR;

   }

 

-  if (TargetStatus == EFI_EXT_SCSI_STATUS_TARGET_CHECK_CONDITION) {

-    DEBUG ((EFI_D_VERBOSE, "ScsiDiskRead16: Check Condition happened!\n"));

+  if ((TargetStatus == EFI_EXT_SCSI_STATUS_TARGET_CHECK_CONDITION) || (EFI_ERROR (ReturnStatus))) {

+    DEBUG ((EFI_D_ERROR, "ScsiDiskRead16: Check Condition happened!\n"));

     Status = DetectMediaParsingSenseKeys (ScsiDiskDevice, ScsiDiskDevice->SenseData, SenseDataLength / sizeof (EFI_SCSI_SENSE_DATA), &Action);

-    if (EFI_ERROR (Status)) {

-      return Status;

-    } else if (Action == ACTION_RETRY_COMMAND_LATER) {

+    if (Action == ACTION_RETRY_COMMAND_LATER) {

       *NeedRetry = TRUE;

       return EFI_DEVICE_ERROR;

+    } else if (Action == ACTION_RETRY_WITH_BACKOFF_ALGO) {

+      if (SectorCount <= 1) {

+        //

+        // Jump out if the operation still fails with one sector transfer length.

+        //

+        *NeedRetry = FALSE;

+        return EFI_DEVICE_ERROR;

+      }

+      //

+      // Try again with half length if the sense data shows we need to retry.

+      //

+      SectorCount >>= 1;

+      *DataLength = SectorCount * ScsiDiskDevice->BlkIo.Media->BlockSize;

+      goto BackOff;

     } else {

       *NeedRetry = FALSE;

       return EFI_DEVICE_ERROR;

@@ -2383,28 +2429,24 @@ ScsiDiskRead16 (
 

   @param  ScsiDiskDevice     The pointer of ScsiDiskDevice

   @param  NeedRetry          The pointer of flag indicates if needs retry if error happens

-  @param  SenseDataArray     NOT used yet in this function

-  @param  NumberOfSenseKeys  The number of sense key

   @param  Timeout            The time to complete the command

   @param  DataBuffer         The buffer to fill with the read out data

   @param  DataLength         The length of buffer

   @param  StartLba           The start logic block address

-  @param  SectorSize         The size of sector

+  @param  SectorCount        The number of blocks to write

 

-  @return  EFI_STATUS is returned by calling ScsiWrite10Command().

+  @return  EFI_STATUS is returned by calling ScsiWrite16Command().

 

 **/

 EFI_STATUS

 ScsiDiskWrite16 (

   IN     SCSI_DISK_DEV         *ScsiDiskDevice,

      OUT BOOLEAN               *NeedRetry,

-     OUT EFI_SCSI_SENSE_DATA   **SenseDataArray,   OPTIONAL

-     OUT UINTN                 *NumberOfSenseKeys,

   IN     UINT64                Timeout,

   IN     UINT8                 *DataBuffer,

   IN OUT UINT32                *DataLength,

   IN     UINT64                StartLba,

-  IN     UINT32                SectorSize

+  IN     UINT32                SectorCount

   )

 {

   EFI_STATUS  Status;

@@ -2414,8 +2456,16 @@ ScsiDiskWrite16 (
   UINT8       TargetStatus;

   UINTN       Action;

 

+  //

+  // Implement a backoff algorithem to resolve some compatibility issues that

+  // some SCSI targets or ATAPI devices couldn't correctly response reading/writing

+  // big data in a single operation.

+  // This algorithem will at first try to execute original request. If the request fails

+  // with media error sense data or else, it will reduce the transfer length to half and

+  // try again till the operation succeeds or fails with one sector transfer length.

+  //

+BackOff:

   *NeedRetry          = FALSE;

-  *NumberOfSenseKeys  = 0;

   Action              = ACTION_NO_ACTION;

   SenseDataLength     = (UINT8) (ScsiDiskDevice->SenseDataNumber * sizeof (EFI_SCSI_SENSE_DATA));

   ReturnStatus = ScsiWrite16Command (

@@ -2428,7 +2478,7 @@ ScsiDiskWrite16 (
                    DataBuffer,

                    DataLength,

                    StartLba,

-                   SectorSize

+                   SectorCount

                    );

   if (ReturnStatus == EFI_NOT_READY) {

     *NeedRetry = TRUE;

@@ -2468,14 +2518,26 @@ ScsiDiskWrite16 (
     return EFI_DEVICE_ERROR;

   }

 

-  if (TargetStatus == EFI_EXT_SCSI_STATUS_TARGET_CHECK_CONDITION) {

-    DEBUG ((EFI_D_VERBOSE, "ScsiDiskWrite16: Check Condition happened!\n"));

+  if ((TargetStatus == EFI_EXT_SCSI_STATUS_TARGET_CHECK_CONDITION) || (EFI_ERROR (ReturnStatus))) {

+    DEBUG ((EFI_D_ERROR, "ScsiDiskWrite16: Check Condition happened!\n"));

     Status = DetectMediaParsingSenseKeys (ScsiDiskDevice, ScsiDiskDevice->SenseData, SenseDataLength / sizeof (EFI_SCSI_SENSE_DATA), &Action);

-    if (EFI_ERROR (Status)) {

-      return Status;

-    } else if (Action == ACTION_RETRY_COMMAND_LATER) {

+    if (Action == ACTION_RETRY_COMMAND_LATER) {

       *NeedRetry = TRUE;

       return EFI_DEVICE_ERROR;

+    } else if (Action == ACTION_RETRY_WITH_BACKOFF_ALGO) {

+      if (SectorCount <= 1) {

+        //

+        // Jump out if the operation still fails with one sector transfer length.

+        //

+        *NeedRetry = FALSE;

+        return EFI_DEVICE_ERROR;

+      }

+      //

+      // Try again with half length if the sense data shows we need to retry.

+      //

+      SectorCount >>= 1;

+      *DataLength = SectorCount * ScsiDiskDevice->BlkIo.Media->BlockSize;

+      goto BackOff;

     } else {

       *NeedRetry = FALSE;

       return EFI_DEVICE_ERROR;