[PATCH] char/agp: Disable frontend without CONFIG_DRM_LEGACY

[Daniel Vetter]

It's probably full of bugs ready for exploiting by userspace. And
there's not going to be any userspace for this without any of the drm
legacy drivers enabled too. So just couple it together.

Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
Cc: David Airlie <airlied at linux.ie>
Cc: Adam Jackson <ajax at redhat.com>
---
 drivers/char/agp/Makefile | 6 +++++-
 drivers/char/agp/agp.h    | 5 +++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/char/agp/Makefile b/drivers/char/agp/Makefile
index cb2497d157f6..90ed8c789e48 100644
--- a/drivers/char/agp/Makefile
+++ b/drivers/char/agp/Makefile
@@ -1,7 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0
-agpgart-y := backend.o frontend.o generic.o isoch.o
+agpgart-y := backend.o generic.o isoch.o
 
+ifeq ($(CONFIG_DRM_LEGACY),y)
 agpgart-$(CONFIG_COMPAT)	+= compat_ioctl.o
+agpgart-y			+= frontend.o
+endif
+
 
 obj-$(CONFIG_AGP)		+= agpgart.o
 obj-$(CONFIG_AGP_ALI)		+= ali-agp.o
diff --git a/drivers/char/agp/agp.h b/drivers/char/agp/agp.h
index 4eb1c772ded7..bb09d64cd51e 100644
--- a/drivers/char/agp/agp.h
+++ b/drivers/char/agp/agp.h
@@ -186,8 +186,13 @@ int agp_add_bridge(struct agp_bridge_data *bridge);
 void agp_remove_bridge(struct agp_bridge_data *bridge);
 
 /* Frontend routines. */
+#if IS_ENABLED(CONFIG_DRM_LEGACY)
 int agp_frontend_initialize(void);
 void agp_frontend_cleanup(void);
+#else
+static inline int agp_frontend_initialize(void) { return 0; }
+static inline void agp_frontend_cleanup(void) {}
+#endif
 
 /* Generic routines. */
 void agp_generic_enable(struct agp_bridge_data *bridge, u32 mode);
-- 
2.29.2