Re: [PATCH] ubi: kill homegrown endian macros

From: Al Viro
Date: Thu May 17 2007 - 17:03:32 EST


On Thu, May 17, 2007 at 01:56:24PM -0700, David Miller wrote:
> From: Artem Bityutskiy <dedekind@xxxxxxxxxxxxx>
> 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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