Re: [RFC PATCH v2 2/4] percpu: Assorted fixes found by strict percpu address space checks

[Nadav Amit]

> On 12 Aug 2024, at 14:57, Uros Bizjak <ubizjak@xxxxxxxxx> wrote:
> Assorted fixes to prevent defconfig build failures when
> strict percpu address space checks will be enabled.
> 
> These show effeciveness of strict percpu address space checks.

[snip]

> --- a/drivers/base/devres.c
> +++ b/drivers/base/devres.c
> @@ -1231,6 +1231,6 @@ void devm_free_percpu(struct device *dev, void __percpu *pdata)
> 	 * devm_free_pages() does.
> 	 */
> 	WARN_ON(devres_release(dev, devm_percpu_release, devm_percpu_match,
> -			       (__force void *)pdata));
> +			       (__force void *)(uintptr_t)pdata));
> 

Since this pattern of casting appears multiple times (sometimes slightly
different), I think it would be best to give a name for this operation
and put it behind a macro.

This would allow both to audit the cases developers move data between
address-spaces, and also make them think whether what they do makes
sense.