Jürgen Keil wrote:
> Hmm, in the past, nothing prevented me from passing
> ioctl parameter structures with a size > 255.
>
> qemu and it's kqemu kernel module are actually using such 
> a big structure with the KQEMU_EXEC ioctl.
>   

Ah, but the encoded size in the ioctl will be truncated.  If you don't 
*rely* on the encoded size, then there is no problem.

> The putback for 6711665 did break kqemu for me,
> because the kernel module was compiled on bits before
> the 6711665 putback, and the qemu application that is
> using the ioctl was compiled after the putback.  The
> old kernel module didn't understand the new ioctl codes
> any more...
>
> So, with the putback for 6711665 we have a small
> binary incompatibility.
>   
Ouch.  How much of a concern is this (for this particular case)?

    -- Garrett
>   
>> I've not seen any feedback on this, so I'm going to go ahead and file a 
>> fast track.  It looks fairly self-evident to me, but if someone has 
>> concerns, it would be good to raise them soon. :-)
>>
>>     -- Garrett  D'Amore wrote:
>>     
>>> Right now, drivers using sys/ioccom.h definitions for _IOR, _IORW, etc. 
>>> are limited to passing structures that are at most 255 bytes.  This 
>>> seems a bit limiting, at least to me.  In particular, other operating 
>>> systems use a value that is much higher -- say 8191 maximum bytes.
>>> ...
>>>       
>  
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