Linux 2.3.15

Linux 2.3.15

There's a rather huge patch-set out there now, taking the 2.3.x series to
2.3.15.
This has a lot of the merge code I've been sent over the last two weeks,
but I will invariably have missed some, if for no other reason than simply
that I got absolutely _flooded_ by people sending me patches.

One of the more interesting things was the SMP pipe cleanup sent by
Richard, but try as I might it was never really stable under load on x86 -
not with the plain semaphores in 2.3.14, and not with the patches Andrea
had either. I assume Richard tested it on an alpha with the much more
well-thought-out atomic operation that the alpha provides.

I ended up rewriting the x86 semaphore code (and some of Richards pipe
code too, for that matter, to get rid of some races in waking things up),
and it doesn't show the problems I saw before, but hey, maybe I just
exchanged one set of problems for another set that I can't trigger any
more. Give me feedback, please.

Other features that don't impact everybody, but are rather major:
 - ATM support merged in
 - firewalling is gone (again), replaced by an even more generic netfilter
   facility.
 - general networking merges and updates
 - Various driver updates (ISDN, ISA PnP, sound, fbcon, usb, intelliport,
   you name it)
 - make system call return type "long" even if the system call only
   returns valid data in the lower order bits - we use the high bits for
   error handling, and some 64-bit architectures care (read: the Merced
   calling conventions want this because they don't automatically extend
   the return type - I bet it will be a new portability issue for other
   programs than just the kernel)

Have fun,
                Linus