Re: [PATCH] USB: ehci: use packed,aligned(4) instead of removingthe packed attribute

[Alan Stern]

On Mon, 20 Jun 2011, Nicolas Pitre wrote:

> > We don't fall into any of these cases, and therefore as you say, we
> > don't need packed.  Arnd and I have both explained this.  So why do you 
> > keep arguing that we do need it?
> 
> Please show me where I keep arguing that you need it?

Not explicitly perhaps.  But you did write:

> Doesn't mean that because it used to work that it is strictly correct.  
> Wouldn't be the first time that a GCC upgrade broke the kernel because 
> the kernel wasn't describing things properly enough.

which strongly implies that "packed" is needed.  You also wrote:

> Yes, but that's a consequence of not being able to access those fields 
> in their naturally aligned position anymore.  Hence the addition of the 
> align attribute to tell the compiler that we know that the structure is 
> still aligned to a certain degree letting the compiler to avoid 
> byte-oriented instructions when possible.

which is predicated on the assumption that "packed" is needed.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/