Re: [PATCH 3/5] drm/exec: Make the drm_exec_until_all_locked() macro more readable

[Christian König <christian.koenig@amd.com>]

On 3/31/26 11:20, Thomas Hellström wrote:
> Use __UNIQUE_ID as done elsewhere in the kernel rather than a
> hand-rolled __PASTE to craft a unique id.
> 
> Also use __maybe_unused rather than (void) to signify that a
> variable, althrough written to, may not actually be used.
> 
> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> ---
>  include/drm/drm_exec.h | 23 ++++++++++++++---------
>  1 file changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h
> index 25db52dd2af0..fc95a979e253 100644
> --- a/include/drm/drm_exec.h
> +++ b/include/drm/drm_exec.h
> @@ -89,6 +89,19 @@ drm_exec_obj(struct drm_exec *exec, unsigned long index)
>  	for (unsigned long _index = (exec)->num_objects - 1;				\
>  	     ((obj) = drm_exec_obj(exec, _index)); --_index)
>  
> +/*
> + * Helper to drm_exec_until_all_locked(). Don't use directly.
> + *
> + * Since labels can't be defined local to the loop's body we use a jump pointer
> + * to make sure that the retry is only used from within the loop's body.
> + */
> +#define __drm_exec_until_all_locked(exec, _label)			\
> +_label:									\
> +	for (void * __maybe_unused __drm_exec_retry_ptr; ({		\
> +		__drm_exec_retry_ptr = &&_label;			\

I think when using __maybe_unused we could also move assigning the variable to the deceleration and drop the extra ({}).

Apart from that looks good to me.

Regards,
Christian.

> +		drm_exec_cleanup(exec);					\
> +	});)
> +
>  /**
>   * drm_exec_until_all_locked - loop until all GEM objects are locked
>   * @exec: drm_exec object
> @@ -96,17 +109,9 @@ drm_exec_obj(struct drm_exec *exec, unsigned long index)
>   * Core functionality of the drm_exec object. Loops until all GEM objects are
>   * locked and no more contention exists. At the beginning of the loop it is
>   * guaranteed that no GEM object is locked.
> - *
> - * Since labels can't be defined local to the loops body we use a jump pointer
> - * to make sure that the retry is only used from within the loops body.
>   */
>  #define drm_exec_until_all_locked(exec)					\
> -__PASTE(__drm_exec_, __LINE__):						\
> -	for (void *__drm_exec_retry_ptr; ({				\
> -		__drm_exec_retry_ptr = &&__PASTE(__drm_exec_, __LINE__);\
> -		(void)__drm_exec_retry_ptr;				\
> -		drm_exec_cleanup(exec);					\
> -	});)
> +	__drm_exec_until_all_locked(exec, __UNIQUE_ID(drm_exec))
>  
>  /**
>   * drm_exec_retry_on_contention - restart the loop to grap all locks