rcu: Make RCU able to tolerate undefined CONFIG_RCU_FANOUT

[linux-2.6-block.git] / kernel / rcu / tree.h

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index a69d3dab2ec4dbf9dc8c412813c84c27363f9378..ac3020fff028900319681221dc4e5fa56cf49778 100644 (file)
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -35,11 +35,23 @@
  * In practice, this did work well going from three levels to four.
  * Of course, your mileage may vary.
  */
+
 #define MAX_RCU_LVLS 4
+
+#ifdef CONFIG_RCU_FANOUT
+#define RCU_FANOUT CONFIG_RCU_FANOUT
+#else /* #ifdef CONFIG_RCU_FANOUT */
+# ifdef CONFIG_64BIT
+# define RCU_FANOUT 64
+# else
+# define RCU_FANOUT 32
+# endif
+#endif /* #else #ifdef CONFIG_RCU_FANOUT */
+
 #define RCU_FANOUT_1         (CONFIG_RCU_FANOUT_LEAF)
-#define RCU_FANOUT_2         (RCU_FANOUT_1 * CONFIG_RCU_FANOUT)
-#define RCU_FANOUT_3         (RCU_FANOUT_2 * CONFIG_RCU_FANOUT)
-#define RCU_FANOUT_4         (RCU_FANOUT_3 * CONFIG_RCU_FANOUT)
+#define RCU_FANOUT_2         (RCU_FANOUT_1 * RCU_FANOUT)
+#define RCU_FANOUT_3         (RCU_FANOUT_2 * RCU_FANOUT)
+#define RCU_FANOUT_4         (RCU_FANOUT_3 * RCU_FANOUT)
 
 #if NR_CPUS <= RCU_FANOUT_1
 #  define RCU_NUM_LVLS       1