[Scst-devel] Report LUNs command failing on SCST target

[Sushree H. <shingne@Brocade.com>]

Hi all,
I am trying to list the LUNs created on the target machine from an initiator, but Report LUNs is failing. I am performing the following steps:

1.       Create 1 LUN - LUN 0 on the target machine using scst admin. I am using Brocade target mode driver. The code to do that is as follows:

[HANDLER vdisk]

#DEVICE <vdisk name>,<device path>,<options>,<block size>

DEVICE disk_0,/vdisks/disk_0.dsk,WRITE_THROUGH,512



[HANDLER vcdrom]

#DEVICE <vdisk name>,<device path>



[GROUP Default]

#USER <user wwn>



[ASSIGNMENT Default]

#DEVICE <device name>,<lun>

DEVICE disk_0,0



[TARGETS enable]

#HOST <wwn identifier>

HOST 10:00:00:05:1e:55:46:59

HOST 10:00:00:05:1e:55:46:5a

HOST 10:01:00:05:1e:55:46:5a

HOST 10:02:00:05:1e:55:46:5a

HOST 10:03:00:05:1e:55:46:5a



[TARGETS disable]

#HOST <wwn identifier>



2.       On the remote initiator (running Brocade initiator mode code), I am running a command that will list the LUNs present on target (it performs a Report LUN command).

3.       On the initiator I get a message saying Report LUNs failed. On the target machine in dmesgs this is was I see:



scst: scst_pre_parse:416:op_name <REPORT LUN> (cmd f6cc3800), direction=2 (expected 2, set yes), transfer_len=8200 (expected len 136314880), flags=2

Oct 26 10:51:04 x3650-017017 kernel: [0]: scst: scst_check_allowed_m

Oct 26 10:51:04 x3650-017017 kernel: [3684]: scst: scst_check_allowed_mem:583:Requested amount of memory (33280 pages) for being executed commands on a device together with the already allocated memory exceeds the allowed maximum 22528. Should youincrease scst_max_dev_cmd_mem?

Oct 26 10:51:04 x3650-017017 kernel: [3684]: scst: scst_prepare_space:810:Unable to allocate or build requested buffer (size 136314880), sending BUSY or QUEUE FULL status

Oct 26 10:51:04 x3650-017017 kernel: [3684]: scst: scst_set_busy:320:Sending BUSY status to initiator 10:00:00:05:1e:55:16:90 (cmds count 1, queue_type 3, sess->init_phase 3)

Could you please tell me why this is happening? Why is scst requesting for more memory that what is asked by the Brocade initiator mode driver?


Thanks,
Sushree