drm/gem: Add evict() callback to drm_gem_object_funcs

Add new common evict() callback to drm_gem_object_funcs and corresponding
drm_gem_object_evict() helper. This is a first step on a way to providing
common GEM-shrinker API for DRM drivers.

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://lore.kernel.org/all/20230108210445.3948344-4-dmitry.osipenko@collabora.com/

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index aa15c52..9b2e786 100644 (file)
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1459,3 +1459,21 @@ tail:
        return freed;
 }
 EXPORT_SYMBOL(drm_gem_lru_scan);
+
+/**
+ * drm_gem_evict - helper to evict backing pages for a GEM object
+ * @obj: obj in question
+ */
+int drm_gem_evict(struct drm_gem_object *obj)
+{
+       dma_resv_assert_held(obj->resv);
+
+       if (!dma_resv_test_signaled(obj->resv, DMA_RESV_USAGE_READ))
+               return -EBUSY;
+
+       if (obj->funcs->evict)
+               return obj->funcs->evict(obj);
+
+       return 0;
+}
+EXPORT_SYMBOL(drm_gem_evict);

diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 772a4ad..c76e651 100644 (file)
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -165,6 +165,16 @@ struct drm_gem_object_funcs {
        int (*mmap)(struct drm_gem_object *obj, struct vm_area_struct *vma);
 
        /**
+        * @evict:
+        *
+        * Evicts gem object out from memory. Used by the drm_gem_object_evict()
+        * helper. Returns 0 on success, -errno otherwise.
+        *
+        * This callback is optional.
+        */
+       int (*evict)(struct drm_gem_object *obj);
+
+       /**
         * @vm_ops:
         *
         * Virtual memory operations used with mmap.
@@ -479,4 +489,6 @@ void drm_gem_lru_move_tail(struct drm_gem_lru *lru, struct drm_gem_object *obj);
 unsigned long drm_gem_lru_scan(struct drm_gem_lru *lru, unsigned nr_to_scan,
                               bool (*shrink)(struct drm_gem_object *obj));
 
+int drm_gem_evict(struct drm_gem_object *obj);
+
 #endif /* __DRM_GEM_H__ */