[rcu:rcu/dev 35/36] kernel/sched/idle.c:184:1: sparse: symbol '__pcpu_scope_cpu_dead_idle' was not declared. Should it be static?

[rcu:rcu/dev 35/36] kernel/sched/idle.c:184:1: sparse: symbol '__pcpu_scope_cpu_dead_idle' was not declared. Should it be static?

[kbuild test robot]

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu/dev
head:   c0d4bae9db364cdb6e1cabad45a045a04d99cf51
commit: 86166c3e1e073e5e037d97bc51c66ef3fe1e90a4 [35/36] cpu: Make CPU-offline idle-loop transition point more precise
reproduce:
  # apt-get install sparse
  git checkout 86166c3e1e073e5e037d97bc51c66ef3fe1e90a4
  make ARCH=x86_64 allmodconfig
  make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

>> kernel/sched/idle.c:184:1: sparse: symbol '__pcpu_scope_cpu_dead_idle' was not declared. Should it be static?

Please review and possibly fold the followup patch.

---
0-DAY kernel test infrastructure                Open Source Technology Center
http://lists.01.org/mailman/listinfo/kbuild                 Intel Corporation

[PATCH rcu] cpu: __pcpu_scope_cpu_dead_idle can be static

[kbuild test robot]

kernel/sched/idle.c:184:1: sparse: symbol '__pcpu_scope_cpu_dead_idle' was not declared. Should it be static?

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
---
 idle.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 42b5102..41354cd 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -181,7 +181,7 @@ exit_idle:
 	start_critical_timings();
 }
 
-DEFINE_PER_CPU(bool, cpu_dead_idle);
+static DEFINE_PER_CPU(bool, cpu_dead_idle);
 
 /*
  * Generic idle loop implementation

Re: [PATCH rcu] cpu: __pcpu_scope_cpu_dead_idle can be static

[Paul E. McKenney]

On Fri, Jan 30, 2015 at 08:43:07AM +0800, kbuild test robot wrote:
> kernel/sched/idle.c:184:1: sparse: symbol '__pcpu_scope_cpu_dead_idle' was not declared. Should it be static?
> 
> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>

It cannot be static, as it is used in kernel/cpu.c.  But it sounds like
sparse would be happier if the DECLARE_PER_CPU() was visible in
kernel/sched/idle.c.  Which would allow the compiler to catch certain
kinds of typos, now that I think about it.

Or am I missing something here?

							Thanx, Paul

> ---
>  idle.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> index 42b5102..41354cd 100644
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -181,7 +181,7 @@ exit_idle:
>  	start_critical_timings();
>  }
> 
> -DEFINE_PER_CPU(bool, cpu_dead_idle);
> +static DEFINE_PER_CPU(bool, cpu_dead_idle);
> 
>  /*
>   * Generic idle loop implementation
>