[PATCH 2/2][RT] powerpc - Make the irq reverse mapping radix tree lockless

[Benjamin Herrenschmidt]

> >   Concurrency between readers and writers are handled by the intrinsic
> > properties of the concurrent radix tree. Concurrency between the tree
> > initialization which is done asynchronously with readers and writers access
> > is handled via an atomic variable (revmap_trees_allocated) set when the
> > tree has been initialized and checked before any reader or writer access
> > just like we used to check for tree.gfp_mask != 0 before.
> 
> Hmm, RCU radix tree is in mainline too for quite a while. I thought
> Ben had already converted this code over ages ago...
> 
> Nothing against the -rt patch, but mainline should probably be updated
> to use RCU as well?

No, I haven't updated that code yet, and yes, we should do it :-)

Cheers,
Ben.