From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Greetings STGT folks,
Here is another go at a proper STGT bs_sg passthrough following input from Tomo and Boaz.
After taking another look, it ended up making alot more sense to split up the queue and
completion paths into struct scsi_lu->cmd_perform() and struct scsi_lu->cmd_done() callers
to support existing 'internal STGT port emulation' and proper struct scsi_cmd -> LUN passthrough
for bs_sg with TCM_Loop ports.
Following Boaz's recommendation, I will next have a look at extending bs_sg to support BSG so we
can actually pass things like SCSI Task Attrs and TMRs into TCM_Loop ports. Until then, please have
a look and let me know if anything is missing. These patches have been tested using STGT/iSCSI <->
TCM_Loop iSCSI Target Ports on v2.6.34 via Open-iSCSI with SPC-4 ALUA. Here is the brief status:
tgtadm --lld iscsi --mode target --op show
Target 1: iqn.2003-01.org.linux-iscsi.target.i686:sn.2aa7bad648f
System information:
Driver: iscsi
State: ready
I_T nexus information:
I_T nexus: 1
Initiator: iqn.1993-08.org.debian:01:2dadf92d0ef
Connection: 0
IP Address: 172.16.201.129
LUN information:
LUN: 0
Type: controller
SCSI ID: IET 00010000
SCSI SN: beaf10
Size: 0 MB
Online: Yes
Removable media: No
Backing store type: rdwr
Backing store path: None
LUN: 1
Type: disk
SCSI ID: IET 00010001
SCSI SN: beaf11
Size: 0 MB
Online: Yes
Removable media: No
Backing store type: sg
Backing store path: /dev/sg7
Account information:
ACL information:
ALL
and on the Open-iSCSI side:
[ 3282.692718] scsi6 : iSCSI Initiator over TCP/IP
[ 3282.979474] scsi 6:0:0:0: RAID IET Controller 0001 PQ: 0 ANSI: 5
[ 3282.982814] scsi 6:0:0:0: Attached scsi generic sg4 type 12
[ 3282.986803] scsi 6:0:0:1: Direct-Access LIO-ORG IBLOCK 3.1 PQ: 0 ANSI: 5
[ 3282.990601] sd 6:0:0:1: [sdf] 3072000 512-byte hardware sectors (1573 MB)
[ 3282.995035] sd 6:0:0:1: [sdf] Write Protect is off
[ 3282.995050] sd 6:0:0:1: [sdf] Mode Sense: 2f 00 00 00
[ 3282.999349] sd 6:0:0:1: [sdf] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 3283.003189] sd 6:0:0:1: [sdf] 3072000 512-byte hardware sectors (1573 MB)
[ 3283.005275] sd 6:0:0:1: [sdf] Write Protect is off
[ 3283.005287] sd 6:0:0:1: [sdf] Mode Sense: 2f 00 00 00
[ 3283.008722] sd 6:0:0:1: [sdf] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 3283.009550] sdf: unknown partition table
[ 3283.091273] sd 6:0:0:1: [sdf] Attached SCSI disk
[ 3283.092361] sd 6:0:0:1: Attached scsi generic sg5 type 0
[ 3283.419050] sd 6:0:0:1: alua: supports implicit and explicit TPGS
[ 3283.426177] sd 6:0:0:1: alua: port group 00 rel port 01
[ 3283.428413] sd 6:0:0:1: alua: port group 00 state A supports TOUSNA
[ 3283.454882] sd 6:0:0:1: alua: port group 00 state A supports TOUSNA
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
Nicholas Bellinger (2):
[tgt]: Add proper STGT LUN backstore passthrough support
[bs_sg]: Add bs_sg_init() for STGT LUN passthrough
usr/bs_sg.c | 20 ++++++++++++
usr/sbc.c | 1 +
usr/target.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----
usr/tgtd.h | 15 +++++++++
4 files changed, 120 insertions(+), 8 deletions(-)
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