tcm_loop: Set residual field for SCSI commands

commit 6cf3fa6918baab0c447f1206f1cef9166ad04864 upstream.

If the target core signals an over- or under-run, tcm_loop should call
scsi_set_resid() to tell the SCSI midlayer about the residual data length.

The difference can be seen by doing something like

    strace -eioctl sg_raw -r 1024 /dev/sda 8 0 0 0 1 0 > /dev/null

and looking at the "resid=" part of the SG_IO ioctl -- after this patch,
the field is correctly reported as 512.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index 81d5832..5d1d4f2 100644 (file)
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -866,6 +866,9 @@ static int tcm_loop_queue_data_in(struct se_cmd *se_cmd)
 
        sc->result = SAM_STAT_GOOD;
        set_host_byte(sc, DID_OK);
+       if ((se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) ||
+           (se_cmd->se_cmd_flags & SCF_UNDERFLOW_BIT))
+               scsi_set_resid(sc, se_cmd->residual_count);
        sc->scsi_done(sc);
        return 0;
 }
@@ -891,6 +894,9 @@ static int tcm_loop_queue_status(struct se_cmd *se_cmd)
                sc->result = se_cmd->scsi_status;
 
        set_host_byte(sc, DID_OK);
+       if ((se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) ||
+           (se_cmd->se_cmd_flags & SCF_UNDERFLOW_BIT))
+               scsi_set_resid(sc, se_cmd->residual_count);
        sc->scsi_done(sc);
        return 0;
 }