[PATCH] rcu/rcu_segcblist: fix -Wmissing-prototypes warnings

[PATCH] rcu/rcu_segcblist: fix -Wmissing-prototypes warnings

[Yi Wang]

We get these warnings when build kernel W=1:
kernel/rcu/rcu_segcblist.c:91:6: warning: no previous prototype for ‘rcu_segcblist_set_len’ [-Wmissing-prototypes]
kernel/rcu/rcu_segcblist.c:107:6: warning: no previous prototype for ‘rcu_segcblist_add_len’ [-Wmissing-prototypes]
kernel/rcu/rcu_segcblist.c:137:6: warning: no previous prototype for ‘rcu_segcblist_xchg_len’ [-Wmissing-prototypes]

Commit eda669a6a2c5 ("rcu/nocb: Atomic ->len field in rcu_segcblist
structure") introduced this, and make the functions static to fix
them.

Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
---
 kernel/rcu/rcu_segcblist.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/rcu_segcblist.c b/kernel/rcu/rcu_segcblist.c
index 495c58c..cbc87b8 100644
--- a/kernel/rcu/rcu_segcblist.c
+++ b/kernel/rcu/rcu_segcblist.c
@@ -88,7 +88,7 @@ struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp)
 }
 
 /* Set the length of an rcu_segcblist structure. */
-void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
+static void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
 {
 #ifdef CONFIG_RCU_NOCB_CPU
 	atomic_long_set(&rsclp->len, v);
@@ -104,7 +104,7 @@ void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
  * This increase is fully ordered with respect to the callers accesses
  * both before and after.
  */
-void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v)
+static void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v)
 {
 #ifdef CONFIG_RCU_NOCB_CPU
 	smp_mb__before_atomic(); /* Up to the caller! */
@@ -134,7 +134,7 @@ void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp)
  * with the actual number of callbacks on the structure.  This exchange is
  * fully ordered with respect to the callers accesses both before and after.
  */
-long rcu_segcblist_xchg_len(struct rcu_segcblist *rsclp, long v)
+static long rcu_segcblist_xchg_len(struct rcu_segcblist *rsclp, long v)
 {
 #ifdef CONFIG_RCU_NOCB_CPU
 	return atomic_long_xchg(&rsclp->len, v);
-- 
1.8.3.1

Re: [PATCH] rcu/rcu_segcblist: fix -Wmissing-prototypes warnings

[Paul E. McKenney]

On Mon, Oct 21, 2019 at 07:49:55AM +0800, Yi Wang wrote:
> We get these warnings when build kernel W=1:
> kernel/rcu/rcu_segcblist.c:91:6: warning: no previous prototype for ‘rcu_segcblist_set_len’ [-Wmissing-prototypes]
> kernel/rcu/rcu_segcblist.c:107:6: warning: no previous prototype for ‘rcu_segcblist_add_len’ [-Wmissing-prototypes]
> kernel/rcu/rcu_segcblist.c:137:6: warning: no previous prototype for ‘rcu_segcblist_xchg_len’ [-Wmissing-prototypes]
> 
> Commit eda669a6a2c5 ("rcu/nocb: Atomic ->len field in rcu_segcblist
> structure") introduced this, and make the functions static to fix
> them.
> 
> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>

Good catch!

However, both Ben Dooks, commit 292d1bb2 ("rcu: Several rcu_segcblist
functions can be static"), and ultimately the kbuild test robot beat
you to it.  This commit is still in -rcu, but will be part of my pull
request to -tip in a couple of weeks.

							Thanx, Paul

> ---
>  kernel/rcu/rcu_segcblist.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/rcu/rcu_segcblist.c b/kernel/rcu/rcu_segcblist.c
> index 495c58c..cbc87b8 100644
> --- a/kernel/rcu/rcu_segcblist.c
> +++ b/kernel/rcu/rcu_segcblist.c
> @@ -88,7 +88,7 @@ struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp)
>  }
>  
>  /* Set the length of an rcu_segcblist structure. */
> -void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
> +static void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
>  {
>  #ifdef CONFIG_RCU_NOCB_CPU
>  	atomic_long_set(&rsclp->len, v);
> @@ -104,7 +104,7 @@ void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
>   * This increase is fully ordered with respect to the callers accesses
>   * both before and after.
>   */
> -void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v)
> +static void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v)
>  {
>  #ifdef CONFIG_RCU_NOCB_CPU
>  	smp_mb__before_atomic(); /* Up to the caller! */
> @@ -134,7 +134,7 @@ void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp)
>   * with the actual number of callbacks on the structure.  This exchange is
>   * fully ordered with respect to the callers accesses both before and after.
>   */
> -long rcu_segcblist_xchg_len(struct rcu_segcblist *rsclp, long v)
> +static long rcu_segcblist_xchg_len(struct rcu_segcblist *rsclp, long v)
>  {
>  #ifdef CONFIG_RCU_NOCB_CPU
>  	return atomic_long_xchg(&rsclp->len, v);
> -- 
> 1.8.3.1
>