drm: etnaviv: Unmap gems on gem_close

So far the unmap from gpu address space only happened when dropping the
last ref in gem_free_object_unlocked, however that is skipped if there's
still multiple handles to the same GEM object.

Since userspace (here mesa) in the case of softpin hands back the memory
region to the pool of available GPU virtual memory closing the handle
via DRM_IOCTL_GEM_CLOSE this can lead to etnaviv_iommu_insert_exact
failing later since userspace thinks the vaddr is available while the
kernel thinks it isn't making the submit fail like

  [E] submit failed: -14 (No space left on device) (etna_cmd_stream_flush:244)

Fix this by unmapping the memory via the .gem_close_object callback.

Signed-off-by: Guido Günther <agx@sigxcpu.org>

drivers/gpu/drm/etnaviv/etnaviv_gem.c

@@ -479,6 +479,38 @@ static const struct etnaviv_gem_ops etnaviv_gem_shmem_ops = {
 	.mmap = etnaviv_gem_mmap_obj,
 };
 
+void etnaviv_gem_close_object(struct drm_gem_object *obj, struct drm_file *unused)
+{
+	struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
+	struct etnaviv_vram_mapping *mapping, *tmp;
+
+	/* Handle this via etnaviv_gem_free_object */
+	if (obj->handle_count == 1)
+		return;
+
+	WARN_ON(is_active(etnaviv_obj));
+
+	/*
+	 * userspace wants to release the handle so we need to remove
+	 * the mapping from the gpu's virtual address space to stay
+	 * in sync.
+	 */
+	list_for_each_entry_safe(mapping, tmp, &etnaviv_obj->vram_list,
+				 obj_node) {
+		struct etnaviv_iommu_context *context = mapping->context;
+
+		WARN_ON(mapping->use);
+
+		if (context) {
+			etnaviv_iommu_unmap_gem(context, mapping);
+			etnaviv_iommu_context_put(context);
+		}
+
+		list_del(&mapping->obj_node);
+		kfree(mapping);
+	}
+}
+
 void etnaviv_gem_free_object(struct drm_gem_object *obj)
 {
 	struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
@@ -538,6 +570,7 @@ static const struct drm_gem_object_funcs etnaviv_gem_object_funcs = {
 	.vmap = etnaviv_gem_prime_vmap,
 	.mmap = etnaviv_gem_mmap,
 	.vm_ops = &vm_ops,
+	.close = etnaviv_gem_close_object,
 };
 
 static int etnaviv_gem_new_impl(struct drm_device *dev, u32 size, u32 flags,