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 simply using:
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_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 $FABRIC_MOD_name' parameters, and actually running the script looks like:
target:/mnt/sdb/lio-core-2.6.git/Documentation/target# python tcm_mod_builder.py -p iSCSI -m tcm_nab5000
tcm_dir: /mnt/sdb/lio-core-2.6.git/Documentation/target/../../
Set fabric_mod_name: tcm_nab5000
Set fabric_mod_dir:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000
Using proto_ident: iSCSI
Creating fabric_mod_dir:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000
Writing file:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/tcm_nab5000_base.h
Using tcm_mod_scan_fabric_ops:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../include/target/target_core_fabric_ops.h
Writing file:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/tcm_nab5000_fabric.c
Writing file:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/tcm_nab5000_fabric.h
Writing file:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/tcm_nab5000_configfs.c
Writing file:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/Kbuild
Writing file:
/mnt/sdb/lio-core-2.6.git/Documentation/target/../../drivers/target/tcm_nab5000/Kconfig
Would you like to add tcm_nab5000to drivers/target/Kbuild..? [yes,no]: yes
Would you like to add tcm_nab5000to drivers/target/Kconfig..? [yes,no]: yes
At the end of tcm_mod_builder.py. the script will ask to add the following line to drivers/target/Kbuild:
obj-$(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() smarter and generate function pointer defs directly from include/target/target_core_fabric_ops.h:struct target_core_fabric_ops structure members.
October 5th, 2010
Nicholas A. Bellinger <nab@linux-iscsi.org>