Re: [PATCH 07/11] drm/xe: Use dma_resv_alloc for lockdep annotation

[Matthew Brost <matthew.brost@intel.com>]

On Thu, Sep 03, 2026 at 03:28:02PM +0200, Christian König wrote:
> Replace the stack-allocated dma_resv in xe_pm_runtime_lockdep_prime()
> with a dynamically allocated one using dma_resv_alloc(). This aligns
> with the move away from embedded dma_resv structures and towards
> reference-counted dynamic allocation.
> 
> The lockdep priming function is used to establish lock ordering
> dependencies between runtime PM and dma_resv locks. The resv is only
> used temporarily for lockdep annotation and is immediately freed after
> use with dma_resv_put().
> 
> If allocation fails, we silently return since this is optional lockdep
> annotation that only affects dependency checking, not functional
> behavior.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>

Reviewed-by: Matthew Brost <matthew.brost@intel.com>

> Assisted-by: Claude:Sonnet 4
> ---
>  drivers/gpu/drm/xe/xe_pm.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> index 99562f691080..33b19bcb6f71 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -762,15 +762,20 @@ static void xe_rpm_might_enter_cb(const struct xe_device *xe)
>   */
>  static void xe_pm_runtime_lockdep_prime(void)
>  {
> -	struct dma_resv lockdep_resv;
> +	struct dma_resv *lockdep_resv;
> +
> +	lockdep_resv = dma_resv_alloc();
> +	if (!lockdep_resv)
> +		return;
>  
> -	dma_resv_init(&lockdep_resv);
>  	lock_map_acquire(&xe_pm_runtime_d3cold_map);
>  	/* D3Cold takes the dma_resv locks to evict bos */
> -	dma_resv_lock(&lockdep_resv, NULL);
> -	dma_resv_unlock(&lockdep_resv);
> +	dma_resv_lock(lockdep_resv, NULL);
> +	dma_resv_unlock(lockdep_resv);
>  	lock_map_release(&xe_pm_runtime_d3cold_map);
>  
> +	dma_resv_put(lockdep_resv);
> +
>  	/* Shrinkers might like to wake up the device under reclaim. */
>  	fs_reclaim_acquire(GFP_KERNEL);
>  	lock_map_acquire(&xe_pm_runtime_nod3cold_map);
> -- 
> 2.43.0
>