Subject: Re: CVS commit: src/sys/sys
To: Jason Thorpe <email@example.com>
From: David Laight <firstname.lastname@example.org>
Date: 12/21/2005 00:09:37
On Tue, Dec 20, 2005 at 08:13:21AM -0800, Jason Thorpe wrote:
> it's pretty annoying that when you change "struct proc" right now,
> random LKMs may break. Moving to opaque types and accessor/mutator
> functions[*] fixes that problem.
Indeed, one of the changes in SVR4 that happened as part of its merge
of SVR3 and the BSD based sunos was that device drives were no longer
allowed to directly access any part of the proc struct or u area.
For an example of on-opaqueness look at all the #defines that linux
exposes to device drivers - not a chance in hell of binary compatibility.
[*] of course there are structures you can decide are immuatable...
David Laight: email@example.com