Date: Thu, 17 May 2007 22:03:19 +0100
From: Al Viro <viro@ftp.linux.org.uk>
To: David Miller <davem@davemloft.net>
Cc: dedekind@infradead.org, hch@lst.de, akpm@osdl.org,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ubi: kill homegrown endian macros
Message-ID: <20070517210319.GT4095@ftp.linux.org.uk>
References: <20070517143200.GA30850@lst.de> <1179413443.3642.49.camel@sauron> <20070517.135624.131107441.davem@davemloft.net>
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On Thu, May 17, 2007 at 01:56:24PM -0700, David Miller wrote:
> From: Artem Bityutskiy <dedekind@infradead.org>
> Date: Thu, 17 May 2007 17:50:43 +0300
> 
> > Well, I see the good side of your change - no home-brewed media<->cpu
> > things. Fair enough and nice. But why don't you make __be32 a struct
> > (just like I do) so that compiler could complain then?
> 
> structs get passed on the stack instead of via registers, regardless
> of size, when passed as arguments on some architectures, so there is a
> terrible performance cost of doing things that way

BTW, the lack of home-grown coversions is not a benefit - it's _nice_ to
have protections against mixing be32 and ubi32, etc.  Avoiding the mess
with struct, OTOH, *is* a benefit.

So I'd rather go with independent bitwise types and conversions done by
use of be... ones + force-cast.  The rest of ubi code remain unchanged.
-
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