Re: [PATCH] IB/srp: Add 64-bit LUN support

[Bart Van Assche <bart.vanassche@sandisk.com>]

Hello Yann,

On 02/10/15 11:13, Yann Droneaud wrote:
> Le lundi 02 février 2015 à 18:21 +0100, Bart Van Assche a écrit :
>> The largest LUN number that has been tested is 0xd2003fff00000000.
>>
>> Checked the following structure sizes with gdb:
>> * sizeof(struct srp_cmd) = 48
>> * sizeof(struct srp_tsk_mgmt) = 48
>> * sizeof(struct srp_aer_req) = 36
> 
> You can use 'pahole' tool to retrieve the size (and layout) of any
> data structure from a .o object file.

Thanks, I will have a look at that tool.

>> The ibmvscsi changes have been compile tested only (on a PPC system).
> 
> The changelog lack of any information about the purpose of 64bit LUNs.
> Please detail a bit why and how.

You might have missed Hannes' patch series through which 64-bit LUN
support was added in the SCSI core and in most SCSI LLD drivers. The
description of one of the patches in that series reads as follows:

   "The SCSI standard defines 64-bit values for LUNs, and large arrays
    employing large or hierarchical LUN numbers become more and more
    common.

    So update the linux SCSI stack to use 64-bit LUN numbers."

Is it OK for you if I resend this patch with that text added in the
patch description ?

Bart.

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