Prevent calling Makefile directly in the kernel/ subdirectory

diff --git a/kernel/Makefile b/kernel/Makefile
index ca85e88d7f4fb26c2549e59841a9a63d9aec8dbf..7881b98bc572ebc1af4e19f8c793c7d1a708d4be 100644 (file)
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -1,3 +1,7 @@
+ifndef IP_SET_MAX
+$(error "Use the toplevel Makefile, not the one in the kernel/ subdirectory")
+endif
+
 ifneq ($(KERNELRELEASE),)
 include Kbuild
 else