Re: [PATCH v2 0/4] hwspinlock: add summary in debugfs

[Matthew Wilcox]

On Mon, Jun 22, 2026 at 10:51:59AM +0200, Wolfram Sang wrote:
> Renesas R-Car SoCs have their spinlocks inside a unit called MFIS. Up to
> R-Car Gen4, there was only one MFIS unit on the SoC. Gen5, though, has
> multiple instances and, thus, multiple spinlock providers. The spinlocks
> are meant for specific cases (AP<->AP, AP<->RT, AP<->SCP...). For
> development on these systems, it is helpful to have an overview of
> registered spinlocks in debugfs. This series adds support for that. The
> first two patches update the radix-tree header to support more lock
> types. The third patch fixes a missing RCU annotation for the slot
> pointer. The fourth patch finally adds the desired functionality.
> 
> Because the radix tree seems to have no dedicated tree nor maintainer, I
> suggest that all these patches go in via hwspinlock. This also keeps the
> dependencies zero.

The radix tree is deprecated.  I don't want to add any new functionality
to it.  Here's a replacement patch to convert hwspinlock to use an
XArray instead of a radix tree.  Compile tested only.