diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
index ee730457bf4e..b89ddd06dabb 100644
--- a/Documentation/gpu/drm-kms-helpers.rst
+++ b/Documentation/gpu/drm-kms-helpers.rst
@@ -411,15 +411,3 @@ Legacy CRTC/Modeset Helper Functions Reference
 
 .. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c
    :export:
-
-SHMEM GEM Helper Reference
-==========================
-
-.. kernel-doc:: drivers/gpu/drm/drm_gem_shmem_helper.c
-   :doc: overview
-
-.. kernel-doc:: include/drm/drm_gem_shmem_helper.h
-   :internal:
-
-.. kernel-doc:: drivers/gpu/drm/drm_gem_shmem_helper.c
-   :export:
diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst
index 8c8540ee859c..8d10e6b38918 100644
--- a/Documentation/gpu/drm-mm.rst
+++ b/Documentation/gpu/drm-mm.rst
@@ -370,6 +370,18 @@ GEM CMA Helper Functions Reference
 .. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c
    :export:
 
+GEM SHMEM Helper Function Reference
+-----------------------------------
+
+.. kernel-doc:: drivers/gpu/drm/drm_gem_shmem_helper.c
+   :doc: overview
+
+.. kernel-doc:: include/drm/drm_gem_shmem_helper.h
+   :internal:
+
+.. kernel-doc:: drivers/gpu/drm/drm_gem_shmem_helper.c
+   :export:
+
 GEM VRAM Helper Functions Reference
 -----------------------------------
 
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 339eee79ea52..3885854e85a9 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -103,7 +103,8 @@ EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
  * @obj: GEM object to free
  *
  * This function cleans up the GEM object state and frees the memory used to
- * store the object itself.
+ * store the object itself. It should be used to implement
+ * &drm_gem_object_funcs.free.
  */
 void drm_gem_shmem_free_object(struct drm_gem_object *obj)
 {
@@ -214,7 +215,8 @@ EXPORT_SYMBOL(drm_gem_shmem_put_pages);
  * @obj: GEM object
  *
  * This function makes sure the backing pages are pinned in memory while the
- * buffer is exported.
+ * buffer is exported. It should only be used to implement
+ * &drm_gem_object_funcs.pin.
  *
  * Returns:
  * 0 on success or a negative error code on failure.
@@ -232,7 +234,7 @@ EXPORT_SYMBOL(drm_gem_shmem_pin);
  * @obj: GEM object
  *
  * This function removes the requirement that the backing pages are pinned in
- * memory.
+ * memory. It should only be used to implement &drm_gem_object_funcs.unpin.
  */
 void drm_gem_shmem_unpin(struct drm_gem_object *obj)
 {
@@ -285,8 +287,14 @@ err_zero_use:
  * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
  * @shmem: shmem GEM object
  *
- * This function makes sure that a virtual address exists for the buffer backing
- * the shmem GEM object.
+ * This function makes sure that a contiguous kernel virtual address mapping
+ * exists for the buffer backing the shmem GEM object.
+ *
+ * This function can be used to implement &drm_gem_object_funcs.vmap. But it can
+ * also be called by drivers directly, in which case it will hide the
+ * differences between dma-buf imported and natively allocated objects.
+ *
+ * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
  *
  * Returns:
  * 0 on success or a negative error code on failure.
@@ -330,7 +338,13 @@ static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem)
  * drm_gem_shmem_vunmap - Unmap a virtual mapping fo a shmem GEM object
  * @shmem: shmem GEM object
  *
- * This function removes the virtual address when use count drops to zero.
+ * This function cleans up a kernel virtual address mapping acquired by
+ * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
+ * zero.
+ *
+ * This function can be used to implement &drm_gem_object_funcs.vmap. But it can
+ * also be called by drivers directly, in which case it will hide the
+ * differences between dma-buf imported and natively allocated objects.
  */
 void drm_gem_shmem_vunmap(struct drm_gem_object *obj, void *vaddr)
 {
@@ -559,6 +573,8 @@ EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
  * @p: DRM printer
  * @indent: Tab indentation level
  * @obj: GEM object
+ *
+ * This implements the &drm_gem_object_funcs.info callback.
  */
 void drm_gem_shmem_print_info(struct drm_printer *p, unsigned int indent,
 			      const struct drm_gem_object *obj)
@@ -577,7 +593,12 @@ EXPORT_SYMBOL(drm_gem_shmem_print_info);
  * @obj: GEM object
  *
  * This function exports a scatter/gather table suitable for PRIME usage by
- * calling the standard DMA mapping API.
+ * calling the standard DMA mapping API. Drivers should not call this function
+ * directly, instead it should only be used as an implementation for
+ * &drm_gem_object_funcs.get_sg_table.
+ *
+ * Drivers who need to acquire an scatter/gather table for objects need to call
+ * drm_gem_shmem_get_pages_sgt() instead.
  *
  * Returns:
  * A pointer to the scatter/gather table of pinned pages or NULL on failure.
@@ -599,6 +620,10 @@ EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
  * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
  * table created.
  *
+ * This is the main function for drivers to get at backing storage, and it hides
+ * and difference between dma-buf imported and natively allocated objects.
+ * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
+ *
  * Returns:
  * A pointer to the scatter/gather table of pinned pages or errno on failure.
  */