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

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

On Mon, Jun 22, 2026 at 02:59:23PM +0100, Matthew Wilcox wrote:
> 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.

Wow, thanks a ton! I have a conference coming up but I still hope to be
able to test your patch this week. We will see...