Re: [PATCH v2] drm/pagemap_util: Ensure proper cache lock management on free

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

On Tue, Feb 24, 2026 at 03:48:33PM +0000, Jonathan Cavitt wrote:
> Static analysis issue:
> 
> Though probably unnecessary given the cache is being freed at this step,
> for the sake of consistency, ensure that the cache lock is always
> unlocked after drm_pagemap_cache_fini.
> 
> v2:
> - Use requested code flow (Maarten)
> 
> Fixes: 77f14f2f2d73f ("drm/pagemap: Add a drm_pagemap cache and shrinker")
> Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
> Cc: Thomas Hellstrom <thomas.hellstrom@linux.intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/drm_pagemap_util.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_pagemap_util.c b/drivers/gpu/drm/drm_pagemap_util.c
> index 14ddb948a32e..66203a19f8f6 100644
> --- a/drivers/gpu/drm/drm_pagemap_util.c
> +++ b/drivers/gpu/drm/drm_pagemap_util.c
> @@ -65,18 +65,13 @@ static void drm_pagemap_cache_fini(void *arg)
>  	drm_dbg(cache->shrinker->drm, "Destroying dpagemap cache.\n");
>  	spin_lock(&cache->lock);
>  	dpagemap = cache->dpagemap;
> -	if (!dpagemap) {
> -		spin_unlock(&cache->lock);
> -		goto out;
> -	}
> +	if (dpagemap && !drm_pagemap_shrinker_cancel(dpagemap))
> +		dpagemap = NULL;
> +	spin_unlock(&cache->lock);
>  
> -	if (drm_pagemap_shrinker_cancel(dpagemap)) {
> -		cache->dpagemap = NULL;
> -		spin_unlock(&cache->lock);
> +	if (dpagemap)
>  		drm_pagemap_destroy(dpagemap, false);

The logic is different here as 'cache->dpagemap' never gets set to NULL
under cache->lock when drm_pagemap_shrinker_cancel returns true.

Also be sure to include intel-xe list for CI too.

Matt

> -	}
>  
> -out:
>  	mutex_destroy(&cache->lookup_mutex);
>  	kfree(cache);
>  }
> -- 
> 2.43.0
>