Re: [PATCH] afs: fsclient.c sparse endian annotations of operation_ID

[Al Viro <viro@ZenIV.linux.org.uk>]

On Wed, Aug 27, 2008 at 04:17:05AM -0700, David Miller wrote:
> From: David Howells <dhowells@redhat.com>
> Date: Wed, 27 Aug 2008 12:12:24 +0100
> 
> > Harvey Harrison <harvey.harrison@gmail.com> wrote:
> > 
> > > +		if (call->operation_ID != __constant_htonl(FSFETCHDATA64)) {
> > 
> > Doesn't htonl() resolve to this for a constant argument?  Following through
> > the definitions, it certainly looks like it ought to:
> 
> Yes it does.
> 
> The __constant_*() interfaces should only be uses for things that
> must be evaluated at compile time (static data initializations,
> switch statement case values etc.).

It's not just "must be evaluated at compile time"; it's "must be C constant
expressions", which is much stricter.  And no, in the case quoted above
__constant_ form is not needed.  Just use htonl()...