[PATCH 21/24][RFC] scsi_tgt: use of sense accessors

[PATCH 21/24][RFC] scsi_tgt: use of sense accessors

[Boaz Harrosh]

  FIXME: I need help with this driver (Pete?)
    I used scsi_sense() in a none const way. But since
    scsi_tgt is the ULD here, it can just access it's own sense
    buffer directly. I did not use scsi_eh_cpy_sense() because
    I did not want the extra copy. Pete will want to use a 260
    bytes buffer here.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Need-help-from: Pete Wyckoff <pw@osc.edu>
---
 drivers/scsi/scsi_tgt_lib.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c
index e01a985..d42f318 100644
--- a/drivers/scsi/scsi_tgt_lib.c
+++ b/drivers/scsi/scsi_tgt_lib.c
@@ -29,6 +29,7 @@
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_transport.h>
 #include <scsi/scsi_tgt.h>
+#include <scsi/scsi_eh.h>
 
 #include "scsi_tgt_priv.h"
 
@@ -397,7 +398,7 @@ static int scsi_tgt_copy_sense(struct scsi_cmnd *cmd, unsigned long uaddr,
 {
 	char __user *p = (char __user *) uaddr;
 
-	if (copy_from_user(cmd->sense_buffer, p,
+	if (copy_from_user(scsi_sense(cmd), p,
 			   min_t(unsigned, SCSI_SENSE_BUFFERSIZE, len))) {
 		printk(KERN_ERR "Could not copy the sense buffer\n");
 		return -EIO;
-- 
1.5.3.3

Re: [PATCH 21/24][RFC] scsi_tgt: use of sense accessors

[Pete Wyckoff]

bharrosh@panasas.com wrote on Mon, 04 Feb 2008 19:53 +0200:
>   FIXME: I need help with this driver (Pete?)
>     I used scsi_sense() in a none const way. But since
>     scsi_tgt is the ULD here, it can just access it's own sense
>     buffer directly. I did not use scsi_eh_cpy_sense() because
>     I did not want the extra copy. Pete will want to use a 260
>     bytes buffer here.
> 
> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
> Need-help-from: Pete Wyckoff <pw@osc.edu>

FYI, I never use scsi_tgt.  Only just pure userspace on the target,
and a dumb ethernet NIC that does not know it is speaking any form
of SCSI.

People who need scsi_tgt have real target-enabled NICs like the
fancy qla4xxx.  Those act as SCSI targets across FC or IP or
whatever and bring commands into the kernel, which then relays them
to a userspace tgtd process, which does the read/write as necessary,
and returns a result code to the NIC to ship back across FC.

So sorry, I won't take a guess at what has to happen here.  But
yeah, you are right that an OSD target implementation would at times
need a sense buffer bigger than 96.  Protocol maximum length for all
sense data is 264.

		-- Pete

Re: [PATCH 21/24][RFC] scsi_tgt: use of sense accessors

[FUJITA Tomonori]

On Tue, 5 Feb 2008 11:21:33 -0500
Pete Wyckoff <pw@osc.edu> wrote:

> bharrosh@panasas.com wrote on Mon, 04 Feb 2008 19:53 +0200:
> >   FIXME: I need help with this driver (Pete?)
> >     I used scsi_sense() in a none const way. But since
> >     scsi_tgt is the ULD here, it can just access it's own sense
> >     buffer directly. I did not use scsi_eh_cpy_sense() because
> >     I did not want the extra copy. Pete will want to use a 260
> >     bytes buffer here.
> > 
> > Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
> > Need-help-from: Pete Wyckoff <pw@osc.edu>
> 
> FYI, I never use scsi_tgt.  Only just pure userspace on the target,
> and a dumb ethernet NIC that does not know it is speaking any form
> of SCSI.

Seems that many people misunderstand STGT iSCSI (and iSER), FCoE, and
SRP (not implemented yet) software target drivers. They don't use the
tgt kernel module. They just run in user space like user-space nfs
daemon.

Re: [PATCH 21/24][RFC] scsi_tgt: use of sense accessors

[Jeff Garzik]

FUJITA Tomonori wrote:
> On Tue, 5 Feb 2008 11:21:33 -0500
> Pete Wyckoff <pw@osc.edu> wrote:
> 
>> bharrosh@panasas.com wrote on Mon, 04 Feb 2008 19:53 +0200:
>>>   FIXME: I need help with this driver (Pete?)
>>>     I used scsi_sense() in a none const way. But since
>>>     scsi_tgt is the ULD here, it can just access it's own sense
>>>     buffer directly. I did not use scsi_eh_cpy_sense() because
>>>     I did not want the extra copy. Pete will want to use a 260
>>>     bytes buffer here.
>>>
>>> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
>>> Need-help-from: Pete Wyckoff <pw@osc.edu>
>> FYI, I never use scsi_tgt.  Only just pure userspace on the target,
>> and a dumb ethernet NIC that does not know it is speaking any form
>> of SCSI.
> 
> Seems that many people misunderstand STGT iSCSI (and iSER), FCoE, and
> SRP (not implemented yet) software target drivers. They don't use the
> tgt kernel module. They just run in user space like user-space nfs
> daemon.

FWIW, some AHCI and other SATA chips implement ATA target mode.  I'm 
watching this SCSI work with interest, hoping that many of the concepts 
(and code?) can be applied to SATA as well.

If for no other reason than I can build a cheap ATA protocol analyzer, 
or bridge.

	Jeff