[ 047/108] tcm_loop: Set residual field for SCSI commands

From: Greg KH
Date: Fri Mar 30 2012 - 17:05:38 EST


3.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Roland Dreier <roland@xxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/target/loopback/tcm_loop.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -905,6 +905,9 @@ static int tcm_loop_queue_data_in(struct

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;
}
@@ -930,6 +933,9 @@ static int tcm_loop_queue_status(struct
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;
}


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