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Date: Tue, 07 Sep 2010 11:40:32 +0200
From: Bernhard Kohl <bernhard.kohl@nsn.com>
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Subject: Re: [Qemu-devel] [PATCH] raw-posix: improve detection of scsi-generic
	devices
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To: ext Christoph Hellwig <hch@lst.de>
Cc: kwolf@redhat.com, Alexander Graf <agraf@suse.de>, Bernhard Kohl <bernhard.kohl@gmx.net>, qemu-devel@nongnu.org

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<bernhard.kohl@gmx.net>
>>>
>>> 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.