1 files changed, 63 insertions, 2 deletions

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index aa43265f4f4f..5d1349c34afd 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -348,8 +348,10 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
 	struct drm_gem_object *obj = &shmem->base;
 	int ret = 0;
 
+	dma_resv_assert_held(obj->resv);
+
 	if (drm_gem_is_imported(obj)) {
-		ret = dma_buf_vmap(obj->dma_buf, map);
+		ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
 	} else {
 		pgprot_t prot = PAGE_KERNEL;
 
@@ -408,8 +410,10 @@ void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
 {
 	struct drm_gem_object *obj = &shmem->base;
 
+	dma_resv_assert_held(obj->resv);
+
 	if (drm_gem_is_imported(obj)) {
-		dma_buf_vunmap(obj->dma_buf, map);
+		dma_buf_vunmap(obj->import_attach->dmabuf, map);
 	} else {
 		dma_resv_assert_held(shmem->base.resv);
 
@@ -800,6 +804,63 @@ drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
 }
 EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);
 
+/**
+ * drm_gem_shmem_prime_import_no_map - Import dmabuf without mapping its sg_table
+ * @dev: Device to import into
+ * @dma_buf: dma-buf object to import
+ *
+ * Drivers that use the shmem helpers but also wants to import dmabuf without
+ * mapping its sg_table can use this as their &drm_driver.gem_prime_import
+ * implementation.
+ */
+struct drm_gem_object *drm_gem_shmem_prime_import_no_map(struct drm_device *dev,
+							 struct dma_buf *dma_buf)
+{
+	struct dma_buf_attachment *attach;
+	struct drm_gem_shmem_object *shmem;
+	struct drm_gem_object *obj;
+	size_t size;
+	int ret;
+
+	if (drm_gem_is_prime_exported_dma_buf(dev, dma_buf)) {
+		/*
+		 * Importing dmabuf exported from our own gem increases
+		 * refcount on gem itself instead of f_count of dmabuf.
+		 */
+		obj = dma_buf->priv;
+		drm_gem_object_get(obj);
+		return obj;
+	}
+
+	attach = dma_buf_attach(dma_buf, dev->dev);
+	if (IS_ERR(attach))
+		return ERR_CAST(attach);
+
+	get_dma_buf(dma_buf);
+
+	size = PAGE_ALIGN(attach->dmabuf->size);
+
+	shmem = __drm_gem_shmem_create(dev, size, true, NULL);
+	if (IS_ERR(shmem)) {
+		ret = PTR_ERR(shmem);
+		goto fail_detach;
+	}
+
+	drm_dbg_prime(dev, "size = %zu\n", size);
+
+	shmem->base.import_attach = attach;
+	shmem->base.resv = dma_buf->resv;
+
+	return &shmem->base;
+
+fail_detach:
+	dma_buf_detach(dma_buf, attach);
+	dma_buf_put(dma_buf);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_no_map);
+
 MODULE_DESCRIPTION("DRM SHMEM memory-management helpers");
 MODULE_IMPORT_NS("DMA_BUF");
 MODULE_LICENSE("GPL v2");