Re: [PATCH v2] sched: Fix compiler warnings

[Vincent Guittot]

On 25 June 2014 03:05, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> Commit 143e1e28cb (sched: Rework sched_domain topology definition)
> introduced a number of functions with a return value of 'const int'.
> gcc doesn't know what to do with that and, if the kernel is compiled
> with W=1, complains with the following warnings whenever sched.h
> is included.
>
> include/linux/sched.h:875:25: warning:
>         type qualifiers ignored on function return type
> include/linux/sched.h:882:25: warning:
>         type qualifiers ignored on function return type
> include/linux/sched.h:889:25: warning:
>         type qualifiers ignored on function return type
> include/linux/sched.h:1002:21: warning:
>         type qualifiers ignored on function return type
>
> Commits fb2aa855 (sched, ARM: Create a dedicated scheduler topology table)
> and 607b45e9a (sched, powerpc: Create a dedicated topology table) introduce
> the same warning in the arm and powerpc code.
>
> Drop 'const' from the function declarations to fix the problem.
>
> The fix for all three patches has to be applied together to avoid
> compilation failures for the affected architectures.
>
> Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>

Acked-by Vincent Guittot <vincent.guittot@xxxxxxxxxx>

> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> v2: Fix problem in all affected architectures with a single patch
>     to avoid compilation errors.
>
>  arch/arm/kernel/topology.c | 2 +-
>  arch/powerpc/kernel/smp.c  | 2 +-
>  include/linux/sched.h      | 8 ++++----
>  3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> index 9d85318..e35d880 100644
> --- a/arch/arm/kernel/topology.c
> +++ b/arch/arm/kernel/topology.c
> @@ -275,7 +275,7 @@ void store_cpu_topology(unsigned int cpuid)
>                 cpu_topology[cpuid].socket_id, mpidr);
>  }
>
> -static inline const int cpu_corepower_flags(void)
> +static inline int cpu_corepower_flags(void)
>  {
>         return SD_SHARE_PKG_RESOURCES  | SD_SHARE_POWERDOMAIN;
>  }
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 51a3ff7..1007fb8 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -747,7 +747,7 @@ int setup_profiling_timer(unsigned int multiplier)
>
>  #ifdef CONFIG_SCHED_SMT
>  /* cpumask of CPUs with asymetric SMT dependancy */
> -static const int powerpc_smt_flags(void)
> +static int powerpc_smt_flags(void)
>  {
>         int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 306f4f0..0376b05 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -872,21 +872,21 @@ enum cpu_idle_type {
>  #define SD_NUMA                        0x4000  /* cross-node balancing */
>
>  #ifdef CONFIG_SCHED_SMT
> -static inline const int cpu_smt_flags(void)
> +static inline int cpu_smt_flags(void)
>  {
>         return SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
>  }
>  #endif
>
>  #ifdef CONFIG_SCHED_MC
> -static inline const int cpu_core_flags(void)
> +static inline int cpu_core_flags(void)
>  {
>         return SD_SHARE_PKG_RESOURCES;
>  }
>  #endif
>
>  #ifdef CONFIG_NUMA
> -static inline const int cpu_numa_flags(void)
> +static inline int cpu_numa_flags(void)
>  {
>         return SD_NUMA;
>  }
> @@ -999,7 +999,7 @@ void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);
>  bool cpus_share_cache(int this_cpu, int that_cpu);
>
>  typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
> -typedef const int (*sched_domain_flags_f)(void);
> +typedef int (*sched_domain_flags_f)(void);
>
>  #define SDTL_OVERLAP   0x01
>
> --
> 1.9.1
>
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