Re: Being more careful about iospace accesses..

[David Woodhouse]

On Thu, 2004-09-16 at 01:10 +0100,
viro@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx wrote:
> On Wed, Sep 15, 2004 at 04:26:12PM -0700, Linus Torvalds wrote:
>  
> >    other bitwise type. You'd get a warnign about incompatible types. Makes 
> >    sense, no?
> >  - you can only do operations that are safe within that byte order. For 
> >    example, it is safe to do a bitwise "&" on two __le16 values. Clearly 
> >    the result is meaningful.
> 
> BTW, so far the most frequent class of endianness bugs had been along the
> lines of
> 	foo->le16_field = cpu_to_le32(12);
> and vice versa.  On big-endian it's a guaranteed FUBAR - think carefully about
> the value that will end up there.

Is that really more frequent than just 'foo->le16_field = 12' ? 
I'm surprised. 

Certainly, it was the frequency of pure assignment without _any_ attempt
at byte-swapping which caused me to introduce the 'jint32_t' et al
structures in jffs2, which even gcc then bitches about if you use them
wrongly.

I suppose I can ditch those now -- I always intended to after a while
anyway.

-- 
dwmw2


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