On Mon, 30 Oct 2023 02:01:50 +0300 Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx> wrote: > Prepare drm_gem_shmem_free() to addition of memory shrinker support > to drm-shmem by adding and using variant of put_pages() that doesn't > touch reservation lock. Reservation shouldn't be touched because lockdep > will trigger a bogus warning about locking contention with fs_reclaim > code paths that can't happen during the time when GEM is freed and > lockdep doesn't know about that. > > Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx> > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 35 +++++++++++++------------- > 1 file changed, 18 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 08b5a57c59d8..24ff2b99e75b 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -128,6 +128,22 @@ struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_create); > > +static void > +drm_gem_shmem_free_pages(struct drm_gem_shmem_object *shmem) > +{ > + struct drm_gem_object *obj = &shmem->base; > + > +#ifdef CONFIG_X86 > + if (shmem->map_wc) > + set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT); > +#endif > + > + drm_gem_put_pages(obj, shmem->pages, > + shmem->pages_mark_dirty_on_put, > + shmem->pages_mark_accessed_on_put); > + shmem->pages = NULL; > +} > + > /** > * drm_gem_shmem_free - Free resources associated with a shmem GEM object > * @shmem: shmem GEM object to free > @@ -142,8 +158,6 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) > if (obj->import_attach) { > drm_prime_gem_destroy(obj, shmem->sgt); > } else { > - dma_resv_lock(shmem->base.resv, NULL); > - > drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count)); > > if (shmem->sgt) { > @@ -157,8 +171,6 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) > If you drop the dma_resv_lock/unlock(), you should also replace the drm_gem_shmem_put_pages_locked() by a drm_gem_shmem_free_pages() in this commit. > drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count)); > drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count)); > - > - dma_resv_unlock(shmem->base.resv); > } > > drm_gem_object_release(obj); > @@ -208,21 +220,10 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) > */ > void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) > { > - struct drm_gem_object *obj = &shmem->base; > - > dma_resv_assert_held(shmem->base.resv); > > - if (refcount_dec_and_test(&shmem->pages_use_count)) { > -#ifdef CONFIG_X86 > - if (shmem->map_wc) > - set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT); > -#endif > - > - drm_gem_put_pages(obj, shmem->pages, > - shmem->pages_mark_dirty_on_put, > - shmem->pages_mark_accessed_on_put); > - shmem->pages = NULL; > - } > + if (refcount_dec_and_test(&shmem->pages_use_count)) > + drm_gem_shmem_free_pages(shmem); > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_put_pages_locked); >