Re: [PATCH 07/10] drm/xe: Use dma_resv_alloc for lockdep annotation

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Early return on dma_resv_alloc() failure unintentionally skips unrelated lockdep annotations.
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commit 2c2f2285d05d44caf485778222c036bce79fbb3f
Author: Christian König <ckoenig.leichtzumerken@gmail.com>

drm/xe: Use dma_resv_alloc for lockdep annotation

This patch replaces the stack-allocated dma_resv in
xe_pm_runtime_lockdep_prime() with a dynamically allocated one to align with
the move towards reference-counted dynamic allocation.

> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> index a5289a9df8d25..13f25d15f5482 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -764,15 +764,20 @@ 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;

[Severity: Low]
Does this unconditional early return unintentionally skip the unrelated
lockdep annotations that follow?

If dma_resv_alloc() fails, it looks like we abort the entire
xe_pm_runtime_lockdep_prime() function. This skips the completely
independent shrinker and nod3cold annotations below. Could this lead to
incomplete lockdep coverage under memory pressure?

>  
> -	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);

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Sashiko AI review · https://sashiko.dev/#/patchset/20260827124910.2245-1-christian.koenig@amd.com?part=7