Re: [Qemu-devel] [PATCH] raw-posix: improve detection of scsi-generic devices

[Alexander Graf]

On 07.09.2010, at 11:40, Bernhard Kohl wrote:

> Am 07.09.2010 04:04, schrieb ext Christoph Hellwig:
>> On Mon, Sep 06, 2010 at 05:39:00PM +0200, Alexander Graf wrote:
>>   
>>> On 06.09.2010, at 17:06, Bernhard Kohl wrote:
>>> 
>>>     
>>>> From: Bernhard Kohl<address@hidden>
>>>> 
>>>> Allow symbolic links which point to /dev/sgX devices.
>>>>       
>>> Couldn't you send an SG_IO test ioctl over and see if it works? I really 
>>> dislike the whole file name magic matching.
>>>     
>> You could, but the result would not be what you expect, given that every
>> /dev/sd* device and more in Linux support it.
>> 
>> What we really need is to stop shoe-horning scsi pass through support
>> into the block layer.  Once we finally get our generic thread offload
>> facilily there is no need for it anymore at all, scsi-generic can
>> simplify offload the SG_IO ioctl and be done with it.  I even have an
>> old prototype for this, just waiting for the generic thread offload
>> to get merged before resurrecting it.
>>   
> 
> Wouldn't it be OK to apply this patch in the meantime before we get
> this complete new solution? I need to handle about 15 /dev/sg* disks
> which are randomly numbered. With this patch I can use the udev
> generated links in /dev/disk/by*, which makes life much easier.
> 

I agree. I'd take this one in for now, as it improves the situation and then 
when all world blossoms we can take Christoph's game-changing framework :).

Kevin, what do you think?


Alex