target: Set additional sense length field in sense data

The target code was not setting the additional sense length field in the
sense data it returned, which meant that at least the Linux stack
ignored the ASC/ASCQ fields.  For example, without this patch, on a
tcm_loop device:

    # sg_raw -v /dev/sda 2 0 0 0 0 0

gives

        cdb to send: 02 00 00 00 00 00
    SCSI Status: Check Condition

    Sense Information:
     Fixed format, current;  Sense key: Illegal Request
      Raw sense data (in hex):
            70 00 05 00 00 00 00 00

while after the patch we correctly get the following (which matches what
a regular disk returns):

        cdb to send: 02 00 00 00 00 00
    SCSI Status: Check Condition

    Sense Information:
     Fixed format, current;  Sense key: Illegal Request
     Additional sense: Invalid command operation code
     Raw sense data (in hex):
            70 00 05 00 00 00 00 0a  00 00 00 00 20 00 00 00
            00 00

Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: stable@kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index a74cb2be74de..daf532bc721a 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -35,6 +35,7 @@
 #define TRANSPORT_SENSE_BUFFER                  SCSI_SENSE_BUFFERSIZE
 /* Used by transport_send_check_condition_and_sense() */
 #define SPC_SENSE_KEY_OFFSET                    2
+#define SPC_ADD_SENSE_LEN_OFFSET                7
 #define SPC_ASC_KEY_OFFSET                      12
 #define SPC_ASCQ_KEY_OFFSET                     13
 #define TRANSPORT_IQN_LEN                       224