From mboxrd@z Thu Jan  1 00:00:00 1970
From: "David S. Miller" <davem@davemloft.net>
Subject: Re: [RFD][PATCH] typhoon and core sample for folding away VLAN
 stuff
Date: Wed, 12 Apr 2006 13:51:43 -0700 (PDT)
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From: Ben Greear <greearb@candelatech.com>
Date: Wed, 12 Apr 2006 13:10:06 -0700

> What is the reasoning for this change?  Is the compiler
> able to optomize the right-hand-side to a constant with your
> change in place?
> 
> > -	if (veth->h_vlan_proto != __constant_htons(ETH_P_8021Q)) {
> > +	if (veth->h_vlan_proto != htons(ETH_P_8021Q)) {
> >  		return -EINVAL;
> >  	}

As a policy, Ben, we only use __constant_htons() in compile
time initializers of data structures.  Otherwise we use the
normal htons().

That's why.