2012-10-05 15:58:15

by Fabio Estevam

Subject: [PATCH] sysctl: Fix 'defined but not used' warning

Since commit 4ae834f767(sched/numa: Implement NUMA home-node selection code)
building a kernel with CONFIG_SMP disabled causes the following warning:

kernel/sysctl.c:259:12: warning: 'min_sched_tunable_scaling' defined but not used [-Wunused-variable]
kernel/sysctl.c:260:12: warning: 'max_sched_tunable_scaling' defined but not used [-Wunused-variable]

Annotate theses variables as '__maybe_unused'.

Signed-off-by: Fabio Estevam <[email protected]>
---
kernel/sysctl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index af25d0c..4bf02e4 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -256,8 +256,8 @@ static int min_sched_granularity_ns = 100000; /* 100 usecs */
static int max_sched_granularity_ns = NSEC_PER_SEC; /* 1 second */
static int min_wakeup_granularity_ns; /* 0 usecs */
static int max_wakeup_granularity_ns = NSEC_PER_SEC; /* 1 second */
-static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
-static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
+static int __maybe_unused min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
+static int __maybe_unused max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
#endif

#ifdef CONFIG_COMPACTION
--
1.7.9.5

2012-10-05 20:44:48

by Arnd Bergmann

Subject: Re: [PATCH] sysctl: Fix 'defined but not used' warning

On Friday 05 October 2012, Fabio Estevam wrote:
> Since commit 4ae834f767(sched/numa: Implement NUMA home-node selection code)
> building a kernel with CONFIG_SMP disabled causes the following warning:
>
> kernel/sysctl.c:259:12: warning: 'min_sched_tunable_scaling' defined but not used [-Wunused-variable]
> kernel/sysctl.c:260:12: warning: 'max_sched_tunable_scaling' defined but not used [-Wunused-variable]
>
> Annotate theses variables as '__maybe_unused'.
>
> Signed-off-by: Fabio Estevam <[email protected]>

Acked-by: Arnd Bergmann <[email protected]>

I noticed the same thing and had a different fix for it, but yours is better anyway.