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Date: Tue, 7 Sep 2010 04:04:48 +0200
From: Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] [PATCH] raw-posix: improve detection of scsi-generic
	devices
Message-ID: <20100907020448.GA1508@lst.de>
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To: Alexander Graf <agraf@suse.de>
Cc: kwolf@redhat.com, Bernhard Kohl <bernhard.kohl@nsn.com>, qemu-devel@nongnu.org, Bernhard Kohl <bernhard.kohl@gmx.net>

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.