Re: [Bug 80711] [PATCH]SG_FLAG_LUN_INHIBIT is no longer implemented and there's not way to prevent the kernel from using the 2nd cdb byte for the LUN

Christoph Hellwig
2014-08-22T15:05:08Z

On Fri, Aug 22, 2014 at 10:53:42AM -0400, Alan Stern wrote:
> Good idea. An enhanced patch is below. If I can get a Tested-By: from
> Tiziano and one or two Acked-By: responses, I'll submit this for the
> current and stable kernels.
>
> Sending the initial INQUIRY command to LUNs larger than 0 involves a
> chicken-and-egg problem -- we don't know whether to fill in the LUN
> bits in the command until we know the SCSI level, and we don't know the
> SCSI level until the INQUIRY response is received. The solution we
> have been using is to store the most recently discovered level in the
> target structure, and use it as a default. If probing starts with LUN
> 0, and if all the LUNs have similar levels, this ought to work.
>
> Except for one thing: The code does store the default level in the
> scsi_target, but forgets to copy it back into each newly allocated
> scsi_device! I added a line to do that into the patch.

Looks good to me,

Acked-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>

Do you want to queue this up in the USB tree? From the looks of what I
have on my plate so far it seems like we could avoid conflicts with it
in the SCSI tree.

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