From owner-freebsd-net  Sat Jun  8  9:16:47 2002
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Date: Sat, 8 Jun 2002 09:16:06 -0700 (PDT)
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To: net@freebsd.org
From: John Polstra <jdp@polstra.com>
Cc: archie@dellroad.org
Subject: Re: m->m_pkthdr.header
In-Reply-To: <200206071955.g57JtrJ65814@arch20m.dellroad.org>
References: <200206071955.g57JtrJ65814@arch20m.dellroad.org>
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In article <200206071955.g57JtrJ65814@arch20m.dellroad.org>,
Archie Cobbs  <archie@dellroad.org> wrote:
> 
> I'd like to get rid of this mbuf field "m->m_pkthdr.header".
[...]
> Any comments/objections?

Yes, please bear in mind that if you change the layout of the mbuf
structures you will probably break binary compatibility with various
commercial network drivers that are shipped in binary form.  That's a
big pain for those of us who are forced to use such drivers.  For that
reason I don't think you should make this kind of change in -stable.
Current is obviously a different kettle of fish, but even there you
should add fillers to replace any structure elements you remove, if
possible.

John
-- 
  John Polstra
  John D. Polstra & Co., Inc.                        Seattle, Washington USA
  "Disappointment is a good sign of basic intelligence."  -- Chögyam Trungpa


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