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From: Wenchao Hao <haowenchao@huawei.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: "Martin K . Petersen" <martin.petersen@oracle.com>,
	Mike Christie <michael.christie@oracle.com>,
	"James E . J . Bottomley" <jejb@linux.ibm.com>,
	Lee Duncan <lduncan@suse.com>, Chris Leech <cleech@redhat.com>,
	<open-iscsi@googlegroups.com>, <linux-scsi@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <liuzhiqiang26@huawei.com>,
	<linfeilong@huawei.com>
Subject: Re: [PATCH 0/2] scsi:donot skip lun if inquiry returns PQ=1 for all hosts
Date: Thu, 15 Dec 2022 17:09:31 +0800	[thread overview]
Message-ID: <57c12317-c229-8cbe-b3d2-d799ea5f554c@huawei.com> (raw)
In-Reply-To: <Y5rHX95Vvl1aLhbp@infradead.org>


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@mail.gmail.com/

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

  parent reply	other threads:[~2022-12-15  9:09 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-14  7:08 Wenchao Hao
2022-12-14  7:08 ` [PATCH 1/2] scsi:core:Add sysfs interface to control if skip lun with PQ=1 Wenchao Hao
2022-12-18 21:37   ` Mike Christie
2022-12-28  8:46     ` Wenchao Hao
2022-12-14  7:08 ` [PATCH 2/2] scsi:iscsi_tcp:Do not skip lun inquiry returns PQ=1 Wenchao Hao
2022-12-15  7:06 ` [PATCH 0/2] scsi:donot skip lun if inquiry returns PQ=1 for all hosts Christoph Hellwig
2022-12-15  8:07   ` Antw: [EXT] " Ulrich Windl
2022-12-16  7:11     ` Christoph Hellwig
2022-12-15  9:09   ` Wenchao Hao [this message]
2022-12-16  7:12     ` Christoph Hellwig
2022-12-16 11:41       ` Wenchao Hao
2022-12-23 15:54         ` Christoph Hellwig
2022-12-28  9:35           ` Wenchao Hao

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