drm/vgem: Implement mmap as GEM object function

Moving the driver-specific mmap code into a GEM object function allows
for using DRM helpers for various mmap callbacks.

The respective vgem functions are being removed. The file_operations
structure vgem_driver_fops is now being created by the helper macro
DEFINE_DRM_GEM_FOPS().
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210624095238.8804-1-tzimmermann@suse.de

drivers/gpu/drm/vgem/vgem_drv.c

@@ -239,32 +239,7 @@ static struct drm_ioctl_desc vgem_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl, DRM_RENDER_ALLOW),
 };
 
-static int vgem_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	unsigned long flags = vma->vm_flags;
-	int ret;
-
-	ret = drm_gem_mmap(filp, vma);
-	if (ret)
-		return ret;
-
-	/* Keep the WC mmaping set by drm_gem_mmap() but our pages
-	 * are ordinary and not special.
-	 */
-	vma->vm_flags = flags | VM_DONTEXPAND | VM_DONTDUMP;
-	return 0;
-}
-
-static const struct file_operations vgem_driver_fops = {
-	.owner		= THIS_MODULE,
-	.open		= drm_open,
-	.mmap		= vgem_mmap,
-	.poll		= drm_poll,
-	.read		= drm_read,
-	.unlocked_ioctl = drm_ioctl,
-	.compat_ioctl	= drm_compat_ioctl,
-	.release	= drm_release,
-};
+DEFINE_DRM_GEM_FOPS(vgem_driver_fops);
 
 static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)
 {
@@ -387,24 +362,12 @@ static void vgem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *ma
 	vgem_unpin_pages(bo);
 }
 
-static int vgem_prime_mmap(struct drm_gem_object *obj,
-			   struct vm_area_struct *vma)
+static int vgem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 {
-	int ret;
-
-	if (obj->size < vma->vm_end - vma->vm_start)
-		return -EINVAL;
-
-	if (!obj->filp)
-		return -ENODEV;
-
-	ret = call_mmap(obj->filp, vma);
-	if (ret)
-		return ret;
-
 	vma_set_file(vma, obj->filp);
 	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 	vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
 
 	return 0;
 }
@@ -416,6 +379,7 @@ static const struct drm_gem_object_funcs vgem_gem_object_funcs = {
 	.get_sg_table = vgem_prime_get_sg_table,
 	.vmap = vgem_prime_vmap,
 	.vunmap = vgem_prime_vunmap,
+	.mmap = vgem_prime_mmap,
 	.vm_ops = &vgem_gem_vm_ops,
 };
 
@@ -433,7 +397,7 @@ static const struct drm_driver vgem_driver = {
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
 	.gem_prime_import = vgem_prime_import,
 	.gem_prime_import_sg_table = vgem_prime_import_sg_table,
-	.gem_prime_mmap = vgem_prime_mmap,
+	.gem_prime_mmap = drm_gem_prime_mmap,
 
 	.name	= DRIVER_NAME,
 	.desc	= DRIVER_DESC,