Re: [PATCH] drm/i915: replace fetch_and_zero() with kernel xchg()

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 27 Apr 2026, Sebastian Brzezinka <sebastian.brzezinka@intel.com> wrote:
> The i915 local fetch_and_zero() macro is a non-atomic
> fetch-and-zero operation defined in i915_utils.h and duplicated in
> display/intel_display_utils.h. Its functionality is equivalent to the
> kernel-provided xchg().

While I dislike having the local fetch_and_zero() macro around, the
usage does not need to be atomic, and there's no need to switch to the
atomic xchg() at all.

Using atomic xchg() gives the wrong impression to the reader that the
atomicity matters when it doesn't.

So that's a no for this patch.

There's been a few attempts at fixing this in the past, one I found was
[1].

[1] https://lore.kernel.org/r/20221209154843.4162814-1-andrzej.hajda@intel.com

> Replace fetch_and_zero() with the kernel provided xchg(), and
> remove the now unused macro definitions from both i915_utils.h and
> display/intel_display_utils.h.
>
> Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>

Where did this happen? Was there a v1? Is this v2?

BR,
Jani.


-- 
Jani Nikula, Intel