Re: [PATCH 0/2] scsi:donot skip lun if inquiry returns PQ=1 for all hosts

[Wenchao Hao]

On 2022/12/15 15:06, Christoph Hellwig wrote:
> On Wed, Dec 14, 2022 at 03:08:44PM +0800, Wenchao Hao wrote:
>> When iSCSI initiator logged in target, the target attached none valid
>> lun but lun0. lun0 is not an valid disk, while it would response
>> inquiry command with PQ=1 and other general scsi commands like probe lun.
>> The others luns of target is added/removed dynamicly.
> 
> I can't find any special casing of LUN0 in RFC7144, can you clarify
> where you think that treats LUN0 any differently than other transports?
> .
This is not described in RFC7144. The sense described above
aims to tell that a dummy lun is useful.

In my opinion, if the addressed lun still response the
inquiry and other commands, we should not skip it,
maybe let the scsi drivers like sd/st/sg to determine
how to handle this lun accordint to the PQ value.

As discussed in following mail, another drivers would
be broken too.

https://lore.kernel.org/linux-scsi/CA+PODjqrRzyJnOKoabMOV4EPByNnL1LgTi+QAKENP3NwUq5YCw@xxxxxxxxxxxxxx/

The key point of my patch is to add one way to map
dummy lun to an sg device.