[PATCH tip/core/rcu 08/14] rcu: Remove return value from rcu_assign_pointer()

Paul E. McKenney
2012-06-15T20:13:43Z

From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

The return value from rcu_assign_pointer() is not used, and using it
would be quite ugly, for example:

q = rcu_assign_pointer(global_p, p);

To prevent this sort of ugliness from spreading, this commit wraps
rcu_assign_pointer() in a do-while loop.

Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/linux/rcupdate.h | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index f2cca02..2f6ec55 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -514,10 +514,10 @@ static inline void rcu_preempt_sleep_check(void)
(_________p1); \
})
#define __rcu_assign_pointer(p, v, space) \
- ({ \
+ do { \
smp_wmb(); \
(p) = (typeof(*v) __force space *)(v); \
- })
+ } while (0)

/**
@@ -852,7 +852,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
*
* Assigns the specified value to the specified RCU-protected
* pointer, ensuring that any concurrent RCU readers will see
- * any prior initialization. Returns the value assigned.
+ * any prior initialization.
*
* Inserts memory barriers on architectures that require them
* (which is most of them), and also prevents the compiler from
--
1.7.8