-#define WARN_ON(x) if (x) {printf("WARNING in %s line %d\n" \
- , __FILE__, __LINE__); }
+#define WARN_ON(condition) ({ \
+ int __ret_warn_on = !!(condition); \
+ if (unlikely(__ret_warn_on)) \
+ printf("WARNING in %s line %d\n", __FILE__, __LINE__); \
+ unlikely(__ret_warn_on); \
+})