Re: Pe: [PATCH v5 1/3] virtio-scsi: first version

[Hannes Reinecke <hare@suse.de>]

On 02/13/2012 02:18 PM, Michael S. Tsirkin wrote:
> On Tue, Feb 14, 2012 at 12:13:36AM +1100, ronnie sahlberg wrote:
>> On Tue, Feb 14, 2012 at 12:00 AM, Michael S. Tsirkin <mst@redhat.com> wrote:
>>> On Mon, Feb 13, 2012 at 02:54:03PM +0200, Dor Laor wrote:
>>>> Only if you use the pci multi-function option but that kills
>>>> standard hot unplug
>>>
>>> It doesn't kill it as such, rather you can't unplug luns individually.
>>
>> Isnt that just a consequence of the current implementation rather than
>> a SCSI limitation?
> 
> Yes.
> 
>> A different way to do hoplug could be to flag all devices as removable
>> in the standard inq page then
>> leave the LUN there persistently and what you remove/add is not the
>> LUN device itself but just the media in the device.
>>
>> Instead of hot-plug remove the LUN,  hot-plug becomes "media eject" or
>> "media insert".
>> The device remains present all time, you never remove it, but instead
>> hot-plug controls if the media is present or not.
>>
>>
>> This would require implementing at least START_STOP_UNIT and
>> PREVENT_ALLOW_MEDIUM_REMOVAL opcode emulation from SBC.
>>
>>
>> regards
>> ronnie sahlberg
> 
> That would work.
>
Or we simply use the Peripheral Qualifier that the device is gone;
eg we could simply set PQ = 1, return sense code 0x25/00 and be done
with ...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
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