drm/cma-helper: Release non-coherent memory with dma_free_noncoherent()

The GEM CMA helpers allocate non-coherent (i.e., cached) backing storage
with dma_alloc_noncoherent(), but release it with dma_free_wc(). Fix this
with a call to dma_free_noncoherent(). Writecombining storage is still
released with dma_free_wc().

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: cf8ccbc72d61 ("drm: Add support for GEM buffers backed by non-coherent memory")
Acked-by: Paul Cercueil <paul@crapouillou.net>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.14+
Link: https://patchwork.freedesktop.org/patch/msgid/20210708175146.10618-1-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index d53388199f34c5602c08e7b07dd844b95b72bf75..9d05674550a4f9d568773bbfd8218648753bc883 100644 (file)
--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -210,8 +210,13 @@ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
                        dma_buf_vunmap(gem_obj->import_attach->dmabuf, &map);
                drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
        } else if (cma_obj->vaddr) {
-               dma_free_wc(gem_obj->dev->dev, cma_obj->base.size,
-                           cma_obj->vaddr, cma_obj->paddr);
+               if (cma_obj->map_noncoherent)
+                       dma_free_noncoherent(gem_obj->dev->dev, cma_obj->base.size,
+                                            cma_obj->vaddr, cma_obj->paddr,
+                                            DMA_TO_DEVICE);
+               else
+                       dma_free_wc(gem_obj->dev->dev, cma_obj->base.size,
+                                   cma_obj->vaddr, cma_obj->paddr);
        }
 
        drm_gem_object_release(gem_obj);