From: Steffen Seeger <seeger@physik.tu-chemnitz.de>
  To  : ggi-develop@eskimo.com
  Date: Tue, 21 Jul 1998 11:45:48 +0200 (MEST)

Re: DMA BLTs

> On Mon, 20 Jul 1998, Steffen Seeger wrote:
> > > On Mon, 20 Jul 1998, Steffen Seeger wrote:
> > > > > 1) If a userspace process passes a pointer to blit from/to,
> > > > > /dev/graphN can tell whether access to the card is focused on
> > > > > that app, but can/how can the kernel identify the calling process and
> > > > > verify the physical region is valid and all permissions are kosher?
> > > > Using the verify_area() call. 
> > > Hasnt this changed somewhat since 2.1.8?
> > IIRC the article from the EXPO98 proceedings about kernel hacking states
> > this as the recommended procedure. How should it be done then?
> 
> http://www.redhat.com:8080/HyperNews/get/devices/exceptions.html

AFAIR that's what the article said:
Use the get_user() macro for small stuff of (compile-time-known) length, 
but if you have variable length, do a verify_area() call. 

> -Dan

			Steffen

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