[PATCH] trigger a syntax error if percpu macros are incorrectly used

[pandora-kernel.git] / include / linux / percpu.h

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index cb9039a..f926490 100644 (file)
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -11,8 +11,14 @@
 #define PERCPU_ENOUGH_ROOM 32768
 #endif
 
-/* Must be an lvalue. */
-#define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); }))
+/*
+ * Must be an lvalue. Since @var must be a simple identifier,
+ * we force a syntax error here if it isn't.
+ */
+#define get_cpu_var(var) (*({                          \
+       extern int simple_indentifier_##var(void);      \
+       preempt_disable();                              \
+       &__get_cpu_var(var); }))
 #define put_cpu_var(var) preempt_enable()
 
 #ifdef CONFIG_SMP