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Hiya Frank,

On Fri, Feb 04, 2005 at 09:44:17PM +0100, Frank van der Linden wrote:
> On Fri, Feb 04, 2005 at 06:36:08PM +0100, Reinoud Zandijk wrote:
> I see where your confusion comes from.. ioctl is wrapped in a piece of
> code which copies in/out data depending on _IOR/_IOW/_IOWR. So, the
> ioctl backend implementations (devices) don't deal with the copyin/copyout.

thats what i thought! but there are situations like in the 
CDIOREADTOCENTRIES where variable length data is transported... shouldn't 
these at least be callable both ways?

> However, ioctl is and always has been a userspace interface.

ok. If so, then how to call operations on a device from say a filingsystem 
other than the standard read/write?

> If you want something usable from kernel space, implement a seperate
> function which can be called by both the ioctl code and your code.

but how would i call the code? i.e. i get a generic block device vnode and 
then have to request the parameters using in-kernel scsipi calls but only 
when its a device handled by scsipi offcource! Thats when i call an ioctl. 
I could offcource add an ioctl for in-kernel use only but that would be 
ugly IMHO.

> Btw, copyout_proc is only to be used when data is to be copied to
> an address space that is not the current process.

Ah! i thought it was a more generic copyout that could determine if its the 
current process or not and/or kernel space...

Cheers,
Reinoud

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