netdev - Re: [PATCH] net: reduce the lines of code

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Message-ID: <1290153111.29509.2.camel@edumazet-laptop>
Date:	Fri, 19 Nov 2010 08:51:51 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Changli Gao <xiaosuo@...il.com>
Cc:	Hagen Paul Pfeifer <hagen@...u.net>,
	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH] net: reduce the lines of code

Le vendredi 19 novembre 2010 à 15:17 +0800, Changli Gao a écrit : 
> On Fri, Nov 19, 2010 at 2:35 PM, Hagen Paul Pfeifer <hagen@...u.net> wrote:
> >
> > On Fri, 19 Nov 2010 10:04:44 +0800, Changli Gao <xiaosuo@...il.com> wrote:
> >> Use macros to reduce the regularity lines.
> >
> > This is complete awkward and does not fix anything - on the contrary it
> > makes it harder to understand the code and no advantage is achieved.
> >
> 
> Although it doesn't fix anything, It can simplify the adding of new
> BPF instructions, one place in filter_def.h instead of two in
> filter.c. I think if some code can be generated automatically, we'd
> better not write it manually, as the chance of error is less when the
> code is generated automatically.
> 

Idea is good, but the way you did it is not.

I have two patches in testing. I'll post them today.

One to remove all the "+ 1" we do in codes[] init

One at check time to replace the divide by a constant instruction
(DIV_K) by a reciprocal one (a multiply at exec time)



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