[tulip] Compile errors with 2.2.16-21

[Donald Becker]

On Mon, 9 Oct 2000, David Shochat wrote:
> Donald Becker wrote:
> > 
> > On Sun, 8 Oct 2000, David Shochat wrote:
> > 
> > > I upgraded my kernel to 2.2.16-21 (to solve a video problem) and now
...
> It was indeed from RedHat but I didn't realize it had anything to do
> with 7.0 or kernel 2.4. I got it because I am trying to get an agpgart
...
> Based on your tip, I checked /usr/include/linux and asm and was
> surprised to see that my symlinks to /usr/src/linux/include/linux and
> asm had been replaced by actual directories (!) as a result of
> installing the "kernel-headers" package.

This change was based on the entirely reasonable notion that most of the
kernel header files should never change.  If the header files did ever
change, libraries and executables would not be portable across kernel
versions.

The idea was good: many header files define interface that should never change.

The implementation was bad, for several reasons
  - Previously we could rely on the current kernel header files existing in
    /usr/include/linux/.  If a user needed to compile a driver for another
    kernel they could specify that explicitly, but building a new kernel
    is (should be!) rare, while updating drivers is relatively common.
  - Many parts of the kernel have private implementation details in the
    public interface files.  Those private details are now enshrined for all
    time with the library header files.
  - Worse, look at blkdev.h for a zillion sets of private implementation
    details mixed together.

So what should have been a structural clean-up turned instead into a ugly
screw-up that will be enshrined for all time.

> Finally, does this mean that tulip cannot (currently) be compiled in a
> 2.4 environment?

There is no 2.4 environment.  The current one is "2.4-pre", and there
have been major interface changes during the 2.4-pre series.

Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993