drm/omapdrm: Set VM flags in GEM-object mmap function

Use the mmap callback in struct drm_gem_object_funcs to set the
VM flags. Replace a number of mmap helpers in omapdrm with their
GEM helper counterparts. Generate DRM's file-operations instance
with GEM's DEFINE_DRM_GEM_FOPS.

The omapdrm driver uses DRM's drm_gem_mmap() helper to prepare
the VMA structure. It then modifies the resulting VMA state in
its own helper omap_gem_mmap_obj(). The patch improves this by
setting up the VMA in the mmap callback in drm_gem_object_funcs,
which is called from within drm_gem_mmap().

Omapdrm's omap_gem_mmap() and omap_gem_mmap() can then be removed
from the driver. A call to drm_gem_mmap() is sufficient for the
mmap operation.

Finally, with the omap functions gone, the drivers file_ops in
omapdriver_fops can be generated with DEFINE_DRM_GEM_FOPS, which
sets DRM's default helpers.

v2:
* detailed commit message (Javier)
* do not set VM_PFNMAP

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Javier Martinez Canillas <[e-mail]>
Acked-by: Maxime Ripard <[e-mail]>
Cc: Tomi Valkeinen <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/omapdrm/omap_drv.c

···
 	return 0;
 }
 
-static const struct file_operations omapdriver_fops = {
-	.owner = THIS_MODULE,
-	.open = drm_open,
-	.unlocked_ioctl = drm_ioctl,
-	.compat_ioctl = drm_compat_ioctl,
-	.release = drm_release,
-	.mmap = omap_gem_mmap,
-	.poll = drm_poll,
-	.read = drm_read,
-	.llseek = noop_llseek,
-};
+DEFINE_DRM_GEM_FOPS(omapdriver_fops);
 
 static const struct drm_driver omap_drm_driver = {
 	.driver_features = DRIVER_MODESET | DRIVER_GEM  |

drivers/gpu/drm/omapdrm/omap_gem.c

···
 	return ret;
 }
 
-/** We override mainly to fix up some of the vm mapping flags.. */
-int omap_gem_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	int ret;
-
-	ret = drm_gem_mmap(filp, vma);
-	if (ret) {
-		DBG("mmap failed: %d", ret);
-		return ret;
-	}
-
-	return omap_gem_mmap_obj(vma->vm_private_data, vma);
-}
-
-int omap_gem_mmap_obj(struct drm_gem_object *obj,
-		struct vm_area_struct *vma)
+static int omap_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 {
 	struct omap_gem_object *omap_obj = to_omap_bo(obj);
 
-	vm_flags_mod(vma, VM_MIXEDMAP, VM_PFNMAP);
+	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP | VM_IO | VM_MIXEDMAP);
 
 	if (omap_obj->flags & OMAP_BO_WC) {
 		vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
···
 		 * address_space (so unmap_mapping_range does what we want,
 		 * in particular in the case of mmap'd dmabufs)
 		 */
-		vma->vm_pgoff = 0;
+		vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
 		vma_set_file(vma, obj->filp);
 
 		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 	}
+
+	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
 
 	return 0;
 }
···
 static const struct drm_gem_object_funcs omap_gem_object_funcs = {
 	.free = omap_gem_free_object,
 	.export = omap_gem_prime_export,
+	.mmap = omap_gem_object_mmap,
 	.vm_ops = &omap_gem_vm_ops,
 };
 

drivers/gpu/drm/omapdrm/omap_gem.h

···
 		struct drm_mode_create_dumb *args);
 
 /* mmap() Interface */
-int omap_gem_mmap(struct file *filp, struct vm_area_struct *vma);
-int omap_gem_mmap_obj(struct drm_gem_object *obj,
-		struct vm_area_struct *vma);
 u64 omap_gem_mmap_offset(struct drm_gem_object *obj);
 size_t omap_gem_mmap_size(struct drm_gem_object *obj);
 

drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c

···
 		struct vm_area_struct *vma)
 {
 	struct drm_gem_object *obj = buffer->priv;
-	int ret = 0;
 
-	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
-	if (ret < 0)
-		return ret;
-
-	return omap_gem_mmap_obj(obj, vma);
+	return drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
 }
 
 static const struct dma_buf_ops omap_dmabuf_ops = {