Re: [PATCH v2] drm/gem: Drop ticket arg to lru_scan()

[Rob Clark]

On Tue, Sep 1, 2026 at 11:57 PM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
>
>
>
> Am 01.09.26 um 18:45 schrieb Rob Clark:
> > 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 panthor shrinker support.  This commit
> > is the followup to remove the unused arg.
> >
> > Signed-off-by: Rob Clark <robin.clark@xxxxxxxxxxxxxxxx>
> > Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
> > Reviewed-by: Liviu Dudau <liviu.dudau@xxxxxxx>
>
> Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

Could someone take this via drm-misc?

BR,
-R

> > ---
> >
> > v2: Drop left over kerneldoc param description, fix panthor spelling
> >
> >   drivers/gpu/drm/drm_gem.c              | 14 +++-----------
> >   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(+), 38 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > index e3ed684ddcf2..3113b4a53b99 100644
> > --- a/drivers/gpu/drm/drm_gem.c
> > +++ b/drivers/gpu/drm/drm_gem.c
> > @@ -1649,15 +1649,13 @@ EXPORT_SYMBOL(drm_gem_lru_move_tail);
> >    * @nr_to_scan: The number of pages to try to reclaim
> >    * @remaining: The number of pages left to reclaim, should be initialized by caller
> >    * @shrink: Callback to try to shrink/reclaim the object.
> > - * @ticket: Optional ww_acquire_ctx context to use for locking
> >    */
> >   unsigned long
> >   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 +1688,17 @@ 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 +1722,6 @@ 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);
> >
>
> --
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
> GF: Jochen Jaser, Andrew McDonald, (HRB 36809, AG Nürnberg)
>
>