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SubjectRe: [PATCH]updated ipc lock patch
On Mon, 28 Oct 2002, Rusty Russell wrote:

> In message <Pine.LNX.4.44.0210271734450.7252-100000@blue1.dev.mcafeelabs.com> y
> ou write:
> > On Mon, 28 Oct 2002, Rusty Russell wrote:
> >
> > > +struct ipc_rcu_kmalloc
> > > +{
> > > + struct rcu_head rcu;
> > > + /* "void *" makes sure alignment of following data is sane. */
> > > + void *data[0];
> > > +};
> >
> > Rusty, why not using gcc "aligned" keywords instead of black magic :
> >
> > void *data[0];
>
> I think it's clearer *why* it's being done than:
>
> struct ipc_rcu_kmalloc
> {
> struct rcu_head rcu;
> } __attribute__((aligned(__alignof__(void *))));

Well, not really Rusty. The above syntax uses documented gcc features
already used inside the kernel, while the fact that void *data[0];
enforces alignment it is not ( to my knowledge ) documented anywhere.
You can also avoid the comment using the aligned syntax ...



- Davide


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