Re: [PATCH] pinctrl: use non-devm kmalloc versions for free functions

From: Tejun Heo
Date: Fri May 05 2017 - 17:54:29 EST

Hello, Maxime.

On Fri, May 05, 2017 at 09:55:18PM +0200, Maxime Ripard wrote:
> > It doesn't make any sense to use the managed functions from the
> > release functions and if you're always matching devm_kmalloc() with
> > devm_kfree(), the only thing it'd do is confusing its readers.
> I wouldn't say that being able to recover and free whatever memory
> leak we might have not making sense, but ok. That was one of the
> options, let's discard it.
> The other one is: refactor the rest of the allocations so that you
> don't have a mix of devm_kmalloc / devm_kfree and kmalloc / kfree for
> the same purpose in the same function.

So, I think the issues here are

1. Use of devm functions in a devres release function. This just
doesn't make sense.

2. If a resource is always allocated and freed in the same function,
there's no reason to use devres for it. I understand that there
can be exceptions for this, e.g. consistency, but it doesn't seem
to apply here.

3. Last but not least, allocating memory to destroy a radix tree. It
should be able to do that without allocating any memory.