[Stgt-devel] Adding Virtial Tape & Changer targets

[Mark Harvey]

A quick introduction.

I am planning on adding support to the stgt for both SSC and SMC
devices with the aim of full Virtual Tape Library support.

I have a working VTL based around the scsi_debug kernel module +
char-device 'back-end' to pass SCSI commands thru to user-space
daemons (which poll the char device looking for work to do). These
daemons act as the SSC or SMC devices.

This VTL I have had working for over 12mths.

However there are some limitations (like a kernel module required for
each OS port).

I want to move this code base across to an iSCSI frame-work and have
finally given up on the Intel iSCSI Reference code base.

There are some aspects of the stgt code that I would like to modify to
make this 'port' a little easier.

There is a lack of a 'generic' pointer for any data structures used
for each target.
i.e. I would like to malloc() required storage space to keep MODE/LOG
SENSE data per target.
===================================================================
--- tgtd.h      (revision 849)
+++ tgtd.h      (working copy)
@@ -47,6 +47,9 @@

        /* TODO: needs a structure for lots of device parameters */
        uint8_t d_sense;
+
+       /* For each device's private use */
+       void    * priv_p;
 };

  struct scsi_cmd {

===================================================================


I suppose what I am asking is:
1. Is this list interested in the SSC & SMC code base as/when I get it working ?
2. Should I submit all code in a couple of big chunks - e.g. smc.c,
ssc.c etc once I have got something worthy to submit ?
Or submit small incremental bits as they are added ? e.g. SCSI command
at a time.

So far, while testing of this code base, I have modified the Makefile
to include the following conditional compile time options. The SBC
code is still included.
e.g.
make KERNELSRC=/usr/src/linux-2.6.20.1 ISCSI=1 SSC=1 SMC=1

Would this be the 'right' way to go, or should it just be compiled
anyway - like the sbc code?


I would also like to see "int (*device_init)()" return a status code
instead of being a "void (*device_init)()", and a corresponding "int
(*device_shutdown)()" defined in the device_type_template.

I have patches if they are welcome.