[tip/core/rcu,06/14] rcu: Remove return value from RCU_INIT_POINTER()

Message ID 1339791195-26389-6-git-send-email-paulmck@linux.vnet.ibm.com
State New
Headers show

Commit Message

Paul E. McKenney June 15, 2012, 8:13 p.m.
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

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

	q = RCU_INIT_POINTER(global_p, p);

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

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 include/linux/rcupdate.h |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

Comments

Josh Triplett June 15, 2012, 8:50 p.m. | #1
On Fri, Jun 15, 2012 at 01:13:07PM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> 
> The return value from RCU_INIT_POINTER() is not used, and using it
> would be quite ugly, for example:
> 
> 	q = RCU_INIT_POINTER(global_p, p);
> 
> To prevent this sort of ugliness from appearing, this commit wraps
> RCU_INIT_POINTER() in a do-while loop.
> 
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Reviewed-by: Josh Triplett <josh@joshtriplett.org>

>  include/linux/rcupdate.h |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> index eb92c21..f2cca02 100644
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -904,7 +904,9 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
>   * the reader-accessible portions of the linked structure.
>   */
>  #define RCU_INIT_POINTER(p, v) \
> -		p = (typeof(*v) __force __rcu *)(v)
> +	do { \
> +		p = (typeof(*v) __force __rcu *)(v); \
> +	} while (0)
>  
>  /**
>   * INIT_RCU_POINTER() - statically initialize an RCU protected pointer
> -- 
> 1.7.8
>

Patch

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index eb92c21..f2cca02 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -904,7 +904,9 @@  static inline notrace void rcu_read_unlock_sched_notrace(void)
  * the reader-accessible portions of the linked structure.
  */
 #define RCU_INIT_POINTER(p, v) \
-		p = (typeof(*v) __force __rcu *)(v)
+	do { \
+		p = (typeof(*v) __force __rcu *)(v); \
+	} while (0)
 
 /**
  * INIT_RCU_POINTER() - statically initialize an RCU protected pointer