On Sun, Jul 01, 2007 at 01:51:43PM +0900, YAMAMOTO Takashi wrote:
> 
> isn't it what FKIOCTL is for?

Hmmm... 'grep -r FKIOCTL src/sys' doesn't give many hits at all.
2 of them are in ioctl_copyin/out - which is never called.

In any case having a kernel resident ioctl buffer is easy to handle,
you just use fp->f_ops->fo_ioctl() instead of sys_ioctl().

The problem here is that the ioctl buffer contained a pointer to another
userspace buffer.  Since we don't want applications to say a buffer is
in kernel space, an additional parameter would have to be passed through
(or maybe a different 'l' so that the kernel vmspace gets used later)
the fo_ioctl() call - and that would be a larger change.

	David

-- 
David Laight: david@l8s.co.uk