[PATCH V4] rcu: change function declaration to bool

[PATCH V4] rcu: change function declaration to bool

[Nicholas Mc Guire]

rcu_cpu_has_callbacks() is declared int. The current declaration was introduced
in commit c0f4dfd4f90f (rcu: Make RCU_FAST_NO_HZ take advantage of numbered
callbacks). But it is actually returning bool and as the function description 
states " * Return true if the specified CPU has any callback....", this probably 
should be a bool as all (3) call-sites currently treat it as bool.

Type-checking coccinelle spatches are being used to locate type mismatches
between function signatures and return values in this case this produced:
./kernel/rcu/tree.c:3538 WARNING: return of wrong type
                    int != bool, 

Patch was compile tested with x86_64_defconfig (implies CONFIG_TREE_RCU=y)

Patch is against 4.1-rc3 (localversion-next is -next-20150511) and fixes

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
---

V4: fix-up to include the origin of the issue being fixed as requeseted by
    Steven Rostedt <rostedt@goodmis.org>.

 kernel/rcu/tree.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index bcc5943..599550c 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3516,7 +3516,7 @@ static int rcu_pending(void)
  * non-NULL, store an indication of whether all callbacks are lazy.
  * (If there are no callbacks, all of them are deemed to be lazy.)
  */
-static int __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy)
+static bool __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy)
 {
 	bool al = true;
 	bool hc = false;
-- 
1.7.10.4

Re: [PATCH V4] rcu: change function declaration to bool

[Josh Triplett]

On Mon, May 11, 2015 at 06:12:27PM +0200, Nicholas Mc Guire wrote:
> rcu_cpu_has_callbacks() is declared int. The current declaration was introduced
> in commit c0f4dfd4f90f (rcu: Make RCU_FAST_NO_HZ take advantage of numbered
> callbacks). But it is actually returning bool and as the function description 
> states " * Return true if the specified CPU has any callback....", this probably 
> should be a bool as all (3) call-sites currently treat it as bool.
> 
> Type-checking coccinelle spatches are being used to locate type mismatches
> between function signatures and return values in this case this produced:
> ./kernel/rcu/tree.c:3538 WARNING: return of wrong type
>                     int != bool, 
> 
> Patch was compile tested with x86_64_defconfig (implies CONFIG_TREE_RCU=y)
> 
> Patch is against 4.1-rc3 (localversion-next is -next-20150511) and fixes
> 
> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>

Seems like a reasonable addition.

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

> ---
> 
> V4: fix-up to include the origin of the issue being fixed as requeseted by
>     Steven Rostedt <rostedt@goodmis.org>.
> 
>  kernel/rcu/tree.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index bcc5943..599550c 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -3516,7 +3516,7 @@ static int rcu_pending(void)
>   * non-NULL, store an indication of whether all callbacks are lazy.
>   * (If there are no callbacks, all of them are deemed to be lazy.)
>   */
> -static int __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy)
> +static bool __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy)
>  {
>  	bool al = true;
>  	bool hc = false;
> -- 
> 1.7.10.4
>