Hello
I have been testing the SRP initiator code to an LIO array here and part of the testing requires me to set the max_sectors_kb size to get 4k I/O's.
This has been due to me having to debug various sg_map issues.
Linux srptest 4.5.0 #2 SMP Thu Apr 7 16:14:38 EDT 2016 x86_64 x86_64 x86_64 GNU/Linux
This kernel has the scan patch from Hannes, as well as the "[PATCH] IB/mlx5: Expose correct max_sge_rd limit" patch.
However, I also tested with vanilla 4.5.0 as well and its the same issue.
For some reason I cannot change the max_sectors_kb size on 4.5.0 here.
I chatted with Ewan about it as well and he reminded me about Martins changes so wondering if that's playing into this.
Take /dev/sdb as an example
[root@srptest queue]# sg_inq --p 0xb0 /dev/sdb
VPD INQUIRY: Block limits page (SBC)
Maximum compare and write length: 1 blocks
Optimal transfer length granularity: 256 blocks
Maximum transfer length: 256 blocks
Optimal transfer length: 768 blocks
Maximum prefetch, xdread, xdwrite transfer length: 0 blocks
[root@srptest queue]# sg_inq --p 0x83 /dev/sdb
VPD INQUIRY: Device Identification page
Designation descriptor number 1, descriptor length: 20
designator_type: NAA, code_set: Binary
associated with the addressed logical unit
NAA 6, IEEE Company_id: 0x1405
Vendor Specific Identifier: 0x3ec95b43d
Vendor Specific Identifier Extension: 0xaf74871a5f1a0117
[0x60014053ec95b43daf74871a5f1a0117]
Designation descriptor number 2, descriptor length: 57
designator_type: T10 vendor identification, code_set: ASCII
associated with the addressed logical unit
vendor id: LIO-ORG
vendor specific: block-1:3ec95b43-daf7-4871-a5f1-a0117ecc9c87
Designation descriptor number 3, descriptor length: 8
transport: SCSI RDMA Protocol (SRP)
designator_type: Relative target port, code_set: Binary
associated with the target port
Relative target port: 0x2
Designation descriptor number 4, descriptor length: 8
transport: SCSI RDMA Protocol (SRP)
designator_type: Target port group, code_set: Binary
associated with the target port
Target port group: 0x0
Designation descriptor number 5, descriptor length: 8
designator_type: Logical unit group, code_set: Binary
associated with the addressed logical unit
Logical unit group: 0x0
Designation descriptor number 6, descriptor length: 48
transport: SCSI RDMA Protocol (SRP)
designator_type: SCSI name string, code_set: UTF-8
associated with the target port
SCSI name string:
0xfe800000000000007cfe900300726e4f,t,0x0001
Designation descriptor number 7, descriptor length: 40
transport: SCSI RDMA Protocol (SRP)
designator_type: SCSI name string, code_set: UTF-8
associated with the target device that contains addressed lu
SCSI name string:
0xfe800000000000007cfe900300726e4f
[root@srptest queue]# cat max_hw_sectors_kb max_sectors_kb
4096
1280
[root@srptest queue]# echo 4096 > max_sectors_kb
-bash: echo: write error: Invalid argument
The exact same targets served by the same array work fine when I test with the RHEL 7.2 kernel
Linux srptest 3.10.0-327.10.1.el7.bz1313814.x86_64 #1 SMP Fri Mar 11 14:10:52 EST 2016 x86_64 x86_64 x86_64 GNU/Linux
[root@srptest ~]# cd /sys/block/sdb/queue
cat max_hw_sectors_kb max_sectors_kb
4096
512
echo 4096 > max_sectors_kb
cat max_hw_sectors_kb max_sectors_kb
4096
4096
[root@srptest ~]# sg_inq --p 0xb0 /dev/sdb
VPD INQUIRY: Block limits page (SBC)
Maximum compare and write length: 1 blocks
Optimal transfer length granularity: 256 blocks
Maximum transfer length: 256 blocks
Optimal transfer length: 768 blocks
Maximum prefetch, xdread, xdwrite transfer length: 0 blocks
This is an SRP device served by LVM via target LIO on my SRp target server
[root@srptest ~]# sg_inq --p 0x83 /dev/sdb
VPD INQUIRY: Device Identification page
Designation descriptor number 1, descriptor length: 20
designator_type: NAA, code_set: Binary
associated with the addressed logical unit
NAA 6, IEEE Company_id: 0x1405
Vendor Specific Identifier: 0x3ec95b43d
Vendor Specific Identifier Extension: 0xaf74871a5f1a0117
[0x60014053ec95b43daf74871a5f1a0117]
Designation descriptor number 2, descriptor length: 57
designator_type: T10 vendor identification, code_set: ASCII
associated with the addressed logical unit
vendor id: LIO-ORG
vendor specific: block-1:3ec95b43-daf7-4871-a5f1-a0117ecc9c87
Designation descriptor number 3, descriptor length: 8
transport: SCSI RDMA Protocol (SRP)
designator_type: Relative target port, code_set: Binary
associated with the target port
Relative target port: 0x1
Designation descriptor number 4, descriptor length: 8
transport: SCSI RDMA Protocol (SRP)
designator_type: Target port group, code_set: Binary
associated with the target port
Target port group: 0x0
Designation descriptor number 5, descriptor length: 8
designator_type: Logical unit group, code_set: Binary
associated with the addressed logical unit
Logical unit group: 0x0
Designation descriptor number 6, descriptor length: 48
transport: SCSI RDMA Protocol (SRP)
designator_type: SCSI name string, code_set: UTF-8
associated with the target port
SCSI name string:
0xfe800000000000007cfe900300726e4e,t,0x0001
Designation descriptor number 7, descriptor length: 40
transport: SCSI RDMA Protocol (SRP)
designator_type: SCSI name string, code_set: UTF-8
associated with the target device that contains addressed lu
SCSI name string:
0xfe800000000000007cfe900300726e4e
Laurence Oberman
Principal Software Maintenance Engineer
Red Hat Global Support Services
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