Message-Id: <1287443775.14039.209.camel@haakon2.linux-iscsi.org>
Date:	Mon, 18 Oct 2010 16:16:15 -0700
From:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To:	Randy Dunlap <randy.dunlap@...cle.com>
Cc:	linux-scsi <linux-scsi@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [RFCv3 20/21] tcm: Add Kbuild and Kconfig for drivers/target
	and Documentation/target/

On Mon, 2010-10-18 at 15:54 -0700, Randy Dunlap wrote:
> On Mon, 18 Oct 2010 15:39:19 -0700 Nicholas A. Bellinger wrote:
> 
> > From: Nicholas Bellinger <nab@...ux-iscsi.org>
> 
> 
> > diff --git a/Documentation/target/tcm_mod_builder.txt b/Documentation/target/tcm_mod_builder.txt
> > new file mode 100644
> > index 0000000..b829e83
> > --- /dev/null
> > +++ b/Documentation/target/tcm_mod_builder.txt
> > @@ -0,0 +1,145 @@
> > +>>>>>>>>>> The TCM v4 fabric module script generator <<<<<<<<<<
> > +
> > +Greetings all,
> > +
> > +This document is intended to be a mini-HOWTO for using the tcm_mod_builder.py
> > +script to generate a brand new functional TCM v4 fabric .ko module of your very own,
> > +that once built can be immediately be loaded to start access the new TCM/ConfigFS
> > +fabric skeleton, by simplying using:
> 
>                        simply
> 

Fixed

> > +
> > +	modprobe $TCM_NEW_MOD
> > +	mkdir -p /sys/kernel/config/target/$TCM_NEW_MOD
> > +
> > +This script will create a new drivers/target/$TCM_NEW_MOD/, and will do the following
> > +
> > +	*) Generate new API callers for drivers/target/target_core_fabric_configs.c logic
> > +	   ->make_nodeacl(), ->drop_nodeacl(), ->make_tpg(), ->drop_tpg()
> > +	   ->make_wwn(), ->drop_wwn().  These are created into $TCM_NEW_MOD/$TCM_NEW_MOD_configfs.c
> > +	*) Generate basic infrastructure for loading/unloading LKMs and TCM/ConfigFS fabric module
> > +	   using a skeleton struct target_core_fabric_ops API template.
> > +	*) Based on user defined T10 Proto_Ident for the new fabric module being built,
> > +	   the TransportID / Initiator and Target WWPN related handlers for
> > +	   SPC-3 persistent reservation are automatically generated in $TCM_NEW_MOD/$TCM_NEW_MOD_fabric.c
> > +	   using drivers/target/target_core_fabric_lib.c logic.
> > +	*) NOP API calls for all other Data I/O path and fabric dependent attribute logic
> > +	   in $TCM_NEW_MOD/$TCM_NEW_MOD_fabric.c
> > +
> > +tcm_mod_builder.py depends upon the mandatory '-p $PROTO_IDENT' and '-m
> > +$FABRIC_MOD_name' paramters, and actually running the script looks like:
> 
>                      parameters,
> 

fixed

> > +
> > +target:/mnt/sdb/lio-core-2.6.git/Documentation/target# python tcm_mod_builder.py -p iSCSI -m tcm_nab5000
> > +tcm_dir: /mnt/sdb/lio-core-2.6.git/Documentation/target/../../
> > +Set fabric_mod_name: tcm_nab5000
> > +Set fabric_mod_dir:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000
> > +Using proto_ident: iSCSI
> > +Creating fabric_mod_dir:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000
> > +Writing file:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/tcm_nab5000_base.h
> > +Using tcm_mod_scan_fabric_ops:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../include/target/target_core_fabric_ops.h
> > +Writing file:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/tcm_nab5000_fabric.c
> > +Writing file:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/tcm_nab5000_fabric.h
> > +Writing file:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/tcm_nab5000_configfs.c
> > +Writing file:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/Kbuild
> > +Writing file:
> > +/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/Kconfig
> > +Would you like to add tcm_nab5000to drivers/target/Kbuild..? [yes,no]: yes
> > +Would you like to add tcm_nab5000to drivers/target/Kconfig..? [yes,no]: yes
> > +
> > +At the end of tcm_mod_builder.py. the script will ask to add the following
> 
>                                 .py,
> 
> > +line for to drivers/target/Kbuild:
> 
>    line to
> 

fixed

> > +
> > +	obj-$(CONFIG_TCM_NAB5000)       += tcm_nab5000/
> > +
> > +and the same for drivers/target/Kconfig:
> > +
> > +	source "drivers/target/tcm_nab5000/Kconfig"
> > +
> > +*) Run 'make menuconfig' and select the new CONFIG_TCM_NAB5000 item:
> > +
> > +	<M>   TCM_NAB5000 fabric module                   
> > +
> > +*) Build using 'make modules', once completed you will have:
> > +
> > +target:/mnt/sdb/lio-core-2.6.git# ls -la drivers/target/tcm_nab5000/
> > +total 1348
> > +drwxr-xr-x 2 root root   4096 2010-10-05 03:23 .
> > +drwxr-xr-x 9 root root   4096 2010-10-05 03:22 ..
> > +-rw-r--r-- 1 root root    282 2010-10-05 03:22 Kbuild
> > +-rw-r--r-- 1 root root    171 2010-10-05 03:22 Kconfig
> > +-rw-r--r-- 1 root root     49 2010-10-05 03:23 modules.order
> > +-rw-r--r-- 1 root root    738 2010-10-05 03:22 tcm_nab5000_base.h
> > +-rw-r--r-- 1 root root   9096 2010-10-05 03:22 tcm_nab5000_configfs.c
> > +-rw-r--r-- 1 root root 191200 2010-10-05 03:23 tcm_nab5000_configfs.o
> > +-rw-r--r-- 1 root root  40504 2010-10-05 03:23 .tcm_nab5000_configfs.o.cmd
> > +-rw-r--r-- 1 root root   5414 2010-10-05 03:22 tcm_nab5000_fabric.c
> > +-rw-r--r-- 1 root root   2016 2010-10-05 03:22 tcm_nab5000_fabric.h
> > +-rw-r--r-- 1 root root 190932 2010-10-05 03:23 tcm_nab5000_fabric.o
> > +-rw-r--r-- 1 root root  40713 2010-10-05 03:23 .tcm_nab5000_fabric.o.cmd
> > +-rw-r--r-- 1 root root 401861 2010-10-05 03:23 tcm_nab5000.ko
> > +-rw-r--r-- 1 root root    265 2010-10-05 03:23 .tcm_nab5000.ko.cmd
> > +-rw-r--r-- 1 root root    459 2010-10-05 03:23 tcm_nab5000.mod.c
> > +-rw-r--r-- 1 root root  23896 2010-10-05 03:23 tcm_nab5000.mod.o
> > +-rw-r--r-- 1 root root  22655 2010-10-05 03:23 .tcm_nab5000.mod.o.cmd
> > +-rw-r--r-- 1 root root 379022 2010-10-05 03:23 tcm_nab5000.o
> > +-rw-r--r-- 1 root root    211 2010-10-05 03:23 .tcm_nab5000.o.cmd
> > +
> > +*) Load the new module, create a lun_0 configfs group, and add new TCM Core
> > +   IBLOCK backstore symlink to port:
> > +
> > +target:/mnt/sdb/lio-core-2.6.git# insmod drivers/target/tcm_nab5000.ko
> > +target:/mnt/sdb/lio-core-2.6.git# mkdir -p /sys/kernel/config/target/nab5000/iqn.foo/tpgt_1/lun/lun_0
> > +target:/mnt/sdb/lio-core-2.6.git# cd /sys/kernel/config/target/nab5000/iqn.foo/tpgt_1/lun/lun_0/
> > +target:/sys/kernel/config/target/nab5000/iqn.foo/tpgt_1/lun/lun_0# ln -s /sys/kernel/config/target/core/iblock_0/lvm_test0 nab5000_port
> > +
> > +target:/sys/kernel/config/target/nab5000/iqn.foo/tpgt_1/lun/lun_0# cd -
> > +target:/mnt/sdb/lio-core-2.6.git# tree /sys/kernel/config/target/nab5000/
> > +/sys/kernel/config/target/nab5000/
> > +|-- discovery_auth
> > +|-- iqn.foo
> > +|   `-- tpgt_1
> > +|       |-- acls
> > +|       |-- attrib
> > +|       |-- lun
> > +|       |   `-- lun_0
> > +|       |       |-- alua_tg_pt_gp
> > +|       |       |-- alua_tg_pt_offline
> > +|       |       |-- alua_tg_pt_status
> > +|       |       |-- alua_tg_pt_write_md
> > +|	|	`-- nab5000_port -> ../../../../../../target/core/iblock_0/lvm_test0
> > +|       |-- np
> > +|       `-- param
> > +`-- version
> > +
> > +target:/mnt/sdb/lio-core-2.6.git# lsmod
> > +Module                  Size  Used by
> > +tcm_nab5000             3935  4 
> > +iscsi_target_mod      193211  0 
> > +target_core_stgt        8090  0 
> > +target_core_pscsi      11122  1 
> > +target_core_file        9172  2 
> > +target_core_iblock      9280  1 
> > +target_core_mod       228575  31
> > +tcm_nab5000,iscsi_target_mod,target_core_stgt,target_core_pscsi,target_core_file,target_core_iblock
> > +libfc                  73681  0 
> > +scsi_debug             56265  0 
> > +scsi_tgt                8666  1 target_core_stgt
> > +configfs               20644  2 target_core_mod
> > +
> > +----------------------------------------------------------------------
> > +
> > +Future TODO items:
> > +
> > +	*) Add more T10 proto_idents 
> > +	*) Make tcm_mod_dump_fabric_ops() smater and generate function pointer
> 
> 	                                  smarter
> 

fixed

> > +	   defs directly from include/target/target_core_fabric_ops.h:struct target_core_fabric_ops 
> > +	   structure members.
> > +
> > +October 5th, 2010
> > +Nicholas A. Bellinger <nab@...ux-iscsi.org>
> 
> 
> I don't get it, but then I haven't followed the scsi target development closely.
> 
> Why the intermediate step of the python script?  I.e., why generate
> source & build/make files?
> 

The main idea here is to produce a functional running configfs skeleton
that can be loaded and configured in /sys/kernel/config/target/$MOD_NAME
using NOPs in order to jump start new TCM fabric module development.  
This allows a fabric module developer to be able to just focus on the
development of fabric dependent kernel I/O pieces, and use the TCM v4.0
generic target_core_fabric_configfs.c framework so that fabric control
plane code 'just works' out of the box for the basic setup.

>>From there the newly generated module can be extended using context
group specific CPP macros based on CONFIGFS_EATTR() code in
include/target/target_core_fabric_configfs.h for fabric dependent knobs,
etc.

Thanks for your review!

--nab


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