Merge branch 'for-2.6.26' of master.kernel.org:/pub/scm/linux/kernel/git/jwboyer...

[linux-2.6] / include / linux / rcupdate.h

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d32c14de270ea28a1490c3241fe71057a1b0f582..8082d6587a0f6544a1ec6c28af922dc01a4b90ea 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -33,8 +33,6 @@
 #ifndef __LINUX_RCUPDATE_H
 #define __LINUX_RCUPDATE_H
 
-#ifdef __KERNEL__
-
 #include <linux/cache.h>
 #include <linux/spinlock.h>
 #include <linux/threads.h>
@@ -174,10 +172,13 @@ struct rcu_head {
  * code.
  */
 
-#define rcu_assign_pointer(p, v)       ({ \
-                                               smp_wmb(); \
-                                               (p) = (v); \
-                                       })
+#define rcu_assign_pointer(p, v) \
+       ({ \
+               if (!__builtin_constant_p(v) || \
+                   ((v) != NULL)) \
+                       smp_wmb(); \
+               (p) = (v); \
+       })
 
 /**
  * synchronize_sched - block until all CPUs have exited any non-preemptive
@@ -242,5 +243,4 @@ extern long rcu_batches_completed_bh(void);
 extern void rcu_init(void);
 extern int rcu_needs_cpu(int cpu);
 
-#endif /* __KERNEL__ */
 #endif /* __LINUX_RCUPDATE_H */