drm/v3d: Add modparam for turning off Big/Super Pages

Add a modparam for turning off Big/Super Pages to make sure that if an
user doesn't want Big/Super Pages enabled, it can disabled it by setting
the modparam to false.

Signed-off-by: Maíra Canal <[e-mail]>
Reviewed-by: Tvrtko Ursulin <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/v3d/v3d_drv.c

···
 #define DRIVER_MINOR 0
 #define DRIVER_PATCHLEVEL 0
 
+/* Only expose the `super_pages` modparam if THP is enabled. */
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+bool super_pages = true;
+module_param_named(super_pages, super_pages, bool, 0400);
+MODULE_PARM_DESC(super_pages, "Enable/Disable Super Pages support.");
+#endif
+
 static int v3d_get_param_ioctl(struct drm_device *dev, void *data,
 			       struct drm_file *file_priv)
 {

drivers/gpu/drm/v3d/v3d_drv.h

···
 void v3d_clean_caches(struct v3d_dev *v3d);
 
 /* v3d_gemfs.c */
+extern bool super_pages;
 void v3d_gemfs_init(struct v3d_dev *v3d);
 void v3d_gemfs_fini(struct v3d_dev *v3d);
 

drivers/gpu/drm/v3d/v3d_gemfs.c

···
 	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
 		goto err;
 
+	/* The user doesn't want to enable Super Pages */
+	if (!super_pages)
+		goto err;
+
 	type = get_fs_type("tmpfs");
 	if (!type)
 		goto err;