Re: [PATCH] drm/gem: Drop ticket arg to lru_scan()

[Liviu Dudau]

On Mon, Aug 31, 2026 at 10:44:08AM -0700, Rob Clark wrote:
> Commit 3392291fc509 ("drm/msm: Fix shrinker deadlock") dropped the only
> use of the ticket arg, but at the time left drm_gem_lru_scan() unchanged
> to avoid conflicts with in-flight pathor shrinker support.  This commit
> is the followup to remove the unused arg.
> 
> Signed-off-by: Rob Clark <robin.clark@xxxxxxxxxxxxxxxx>

With the panthor spelling fixed:

Reviewed-by: Liviu Dudau <liviu.dudau@xxxxxxx>

Best regards,
Liviu

> ---
>  drivers/gpu/drm/drm_gem.c              | 13 +++----------
>  drivers/gpu/drm/msm/msm_gem_shrinker.c | 22 ++++++++++------------
>  drivers/gpu/drm/panthor/panthor_gem.c  | 14 ++++++--------
>  drivers/gpu/drm/panthor/panthor_mmu.c  |  5 ++---
>  drivers/gpu/drm/panthor/panthor_mmu.h  |  3 +--
>  include/drm/drm_gem.h                  |  3 +--
>  6 files changed, 23 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index e3ed684ddcf2..15acb958ecd5 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -1656,8 +1656,7 @@ drm_gem_lru_scan(struct drm_device *dev,
>  		 struct drm_gem_lru *lru,
>  		 unsigned int nr_to_scan,
>  		 unsigned long *remaining,
> -		 bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket),
> -		 struct ww_acquire_ctx *ticket)
> +		 bool (*shrink)(struct drm_gem_object *obj))
>  {
>  	struct drm_gem_lru still_in_lru;
>  	struct drm_gem_object *obj;
> @@ -1690,20 +1689,17 @@ drm_gem_lru_scan(struct drm_device *dev,
>  		 */
>  		mutex_unlock(&dev->gem_lru_mutex);
>  
> -		if (ticket)
> -			ww_acquire_init(ticket, &reservation_ww_class);
> -
>  		/*
>  		 * Note that this still needs to be trylock, since we can
>  		 * hit shrinker in response to trying to get backing pages
>  		 * for this obj (ie. while it's lock is already held)
>  		 */
> -		if (!ww_mutex_trylock(&obj->resv->lock, ticket)) {
> +		if (!ww_mutex_trylock(&obj->resv->lock, NULL)) {
>  			*remaining += obj->size >> PAGE_SHIFT;
>  			goto tail;
>  		}
>  
> -		if (shrink(obj, ticket)) {
> +		if (shrink(obj)) {
>  			freed += obj->size >> PAGE_SHIFT;
>  
>  			/*
> @@ -1727,9 +1723,6 @@ drm_gem_lru_scan(struct drm_device *dev,
>  
>  		dma_resv_unlock(obj->resv);
>  
> -		if (ticket)
> -			ww_acquire_fini(ticket);
> -
>  tail:
>  		drm_gem_object_put(obj);
>  		mutex_lock(&dev->gem_lru_mutex);
> diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
> index 9d2788f79ace..3514d5c84989 100644
> --- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
> +++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
> @@ -102,7 +102,7 @@ with_vm_locks(void (*fn)(struct drm_gem_object *obj),
>  }
>  
>  static bool
> -purge(struct drm_gem_object *obj, struct ww_acquire_ctx *unused)
> +purge(struct drm_gem_object *obj)
>  {
>  	if (!is_purgeable(to_msm_bo(obj)))
>  		return false;
> @@ -114,7 +114,7 @@ purge(struct drm_gem_object *obj, struct ww_acquire_ctx *unused)
>  }
>  
>  static bool
> -evict(struct drm_gem_object *obj, struct ww_acquire_ctx *unused)
> +evict(struct drm_gem_object *obj)
>  {
>  	if (is_unevictable(to_msm_bo(obj)))
>  		return false;
> @@ -133,21 +133,21 @@ wait_for_idle(struct drm_gem_object *obj)
>  }
>  
>  static bool
> -active_purge(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
> +active_purge(struct drm_gem_object *obj)
>  {
>  	if (!wait_for_idle(obj))
>  		return false;
>  
> -	return purge(obj, ticket);
> +	return purge(obj);
>  }
>  
>  static bool
> -active_evict(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
> +active_evict(struct drm_gem_object *obj)
>  {
>  	if (!wait_for_idle(obj))
>  		return false;
>  
> -	return evict(obj, ticket);
> +	return evict(obj);
>  }
>  
>  static unsigned long
> @@ -156,7 +156,7 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
>  	struct msm_drm_private *priv = shrinker->private_data;
>  	struct {
>  		struct drm_gem_lru *lru;
> -		bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket);
> +		bool (*shrink)(struct drm_gem_object *obj);
>  		bool cond;
>  		unsigned long freed;
>  		unsigned long remaining;
> @@ -180,8 +180,7 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
>  		stages[i].freed =
>  			drm_gem_lru_scan(priv->dev, stages[i].lru, nr,
>  					 &stages[i].remaining,
> -					 stages[i].shrink,
> -					 NULL);
> +					 stages[i].shrink);
>  		nr -= stages[i].freed;
>  		freed += stages[i].freed;
>  		remaining += stages[i].remaining;
> @@ -222,7 +221,7 @@ msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan)
>  static const int vmap_shrink_limit = 15;
>  
>  static bool
> -vmap_shrink(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
> +vmap_shrink(struct drm_gem_object *obj)
>  {
>  	if (!is_vunmapable(to_msm_bo(obj)))
>  		return false;
> @@ -250,8 +249,7 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
>  		unmapped += drm_gem_lru_scan(priv->dev, lrus[idx],
>  					     vmap_shrink_limit - unmapped,
>  					     &remaining,
> -					     vmap_shrink,
> -					     NULL);
> +					     vmap_shrink);
>  	}
>  
>  	*(unsigned long *)ptr += unmapped;
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c
> index 54535bae2b0c..17408f832af3 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.c
> +++ b/drivers/gpu/drm/panthor/panthor_gem.c
> @@ -1392,8 +1392,7 @@ panthor_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
>  	return count ? count : SHRINK_EMPTY;
>  }
>  
> -static bool panthor_gem_try_evict_no_resv_wait(struct drm_gem_object *obj,
> -					       struct ww_acquire_ctx *ticket)
> +static bool panthor_gem_try_evict_no_resv_wait(struct drm_gem_object *obj)
>  {
>  	/*
>  	 * Track last locked entry for unwinding locks in error and
> @@ -1479,8 +1478,7 @@ static bool panthor_gem_try_evict_no_resv_wait(struct drm_gem_object *obj,
>  	return ret == 0;
>  }
>  
> -static bool panthor_gem_try_evict(struct drm_gem_object *obj,
> -				  struct ww_acquire_ctx *ticket)
> +static bool panthor_gem_try_evict(struct drm_gem_object *obj)
>  {
>  	struct panthor_gem_object *bo = to_panthor_bo(obj);
>  
> @@ -1488,7 +1486,7 @@ static bool panthor_gem_try_evict(struct drm_gem_object *obj,
>  	if (dma_resv_wait_timeout(obj->resv, DMA_RESV_USAGE_BOOKKEEP, false, 10) <= 0)
>  		return false;
>  
> -	return panthor_gem_try_evict_no_resv_wait(&bo->base, ticket);
> +	return panthor_gem_try_evict_no_resv_wait(&bo->base);
>  }
>  
>  static unsigned long
> @@ -1503,13 +1501,13 @@ panthor_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
>  
>  	freed += drm_gem_lru_scan(&ptdev->base, &ptdev->reclaim.unused,
>  				  sc->nr_to_scan - freed, &remaining,
> -				  panthor_gem_try_evict_no_resv_wait, NULL);
> +				  panthor_gem_try_evict_no_resv_wait);
>  	if (freed >= sc->nr_to_scan)
>  		goto out;
>  
>  	freed += drm_gem_lru_scan(&ptdev->base, &ptdev->reclaim.mmapped,
>  				  sc->nr_to_scan - freed, &remaining,
> -				  panthor_gem_try_evict_no_resv_wait, NULL);
> +				  panthor_gem_try_evict_no_resv_wait);
>  	if (freed >= sc->nr_to_scan)
>  		goto out;
>  
> @@ -1523,7 +1521,7 @@ panthor_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
>  
>  	freed += drm_gem_lru_scan(&ptdev->base, &ptdev->reclaim.gpu_mapped_shared,
>  				  sc->nr_to_scan - freed, &remaining,
> -				  panthor_gem_try_evict, NULL);
> +				  panthor_gem_try_evict);
>  
>  out:
>  #ifdef CONFIG_DEBUG_FS
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
> index e10dbd18d8cf..ab070bc74857 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -3133,8 +3133,7 @@ int panthor_vm_prepare_mapped_bos_resvs(struct drm_exec *exec, struct panthor_vm
>  unsigned long
>  panthor_mmu_reclaim_priv_bos(struct panthor_device *ptdev,
>  			     unsigned int nr_to_scan, unsigned long *remaining,
> -			     bool (*shrink)(struct drm_gem_object *,
> -					    struct ww_acquire_ctx *))
> +			     bool (*shrink)(struct drm_gem_object *))
>  {
>  	unsigned long freed = 0;
>  	LIST_HEAD(remaining_vms);
> @@ -3160,7 +3159,7 @@ panthor_mmu_reclaim_priv_bos(struct panthor_device *ptdev,
>  
>  		freed += drm_gem_lru_scan(&ptdev->base, &vm->reclaim.lru,
>  					  nr_to_scan - freed,
> -					  remaining, shrink, NULL);
> +					  remaining, shrink);
>  
>  		mutex_lock(&ptdev->base.gem_lru_mutex);
>  
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.h b/drivers/gpu/drm/panthor/panthor_mmu.h
> index 3522fbbce369..abc36e7204be 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.h
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.h
> @@ -52,8 +52,7 @@ int panthor_vm_evict_bo_mappings_locked(struct panthor_gem_object *bo);
>  unsigned long
>  panthor_mmu_reclaim_priv_bos(struct panthor_device *ptdev,
>  			     unsigned int nr_to_scan, unsigned long *remaining,
> -			     bool (*shrink)(struct drm_gem_object *,
> -					    struct ww_acquire_ctx *));
> +			     bool (*shrink)(struct drm_gem_object *));
>  int panthor_vm_prepare_mapped_bos_resvs(struct drm_exec *exec,
>  					struct panthor_vm *vm,
>  					u32 slot_count);
> diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> index 8a704f6a65c1..ffa607c91aa2 100644
> --- a/include/drm/drm_gem.h
> +++ b/include/drm/drm_gem.h
> @@ -616,8 +616,7 @@ drm_gem_lru_scan(struct drm_device *dev,
>  		 struct drm_gem_lru *lru,
>  		 unsigned int nr_to_scan,
>  		 unsigned long *remaining,
> -		 bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket),
> -		 struct ww_acquire_ctx *ticket);
> +		 bool (*shrink)(struct drm_gem_object *obj));
>  
>  int drm_gem_evict_locked(struct drm_gem_object *obj);
>  
> -- 
> 2.55.0
> 

-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
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