Re: [PATCH] sched: Remove nested extern

[Josh Triplett <josh@joshtriplett.org>]

On Mon, Sep 22, 2014 at 10:55:11AM -0700, Mark D Rustad wrote:
> Avoid W=2 nested-externs warning by moving the nested extern to
> a normal extern. This eliminates that warning which is generated
> for every inclusion of sched.h in a kernel build when W=2 is used.
> This also removes a point of maintenance if the definition of
> delayacct_on were ever to change.
> 
> Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>

This seems sensible, and makes much more sense than wrapping the extern
in a directive to disable warnings.

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

>  include/linux/delayacct.h |    1 -
>  include/linux/sched.h     |    3 ++-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h
> index 6cee17c22313..51229790af00 100644
> --- a/include/linux/delayacct.h
> +++ b/include/linux/delayacct.h
> @@ -30,7 +30,6 @@
>  
>  #ifdef CONFIG_TASK_DELAY_ACCT
>  
> -extern int delayacct_on;	/* Delay accounting turned on/off */
>  extern struct kmem_cache *delayacct_cache;
>  extern void delayacct_init(void);
>  extern void __delayacct_tsk_init(struct task_struct *);
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 5c2c885ee52b..1f1dcfdcd92c 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -825,6 +825,8 @@ struct task_delay_info {
>  	u64 freepages_delay;	/* wait for memory reclaim */
>  	u32 freepages_count;	/* total count of memory reclaim */
>  };
> +
> +extern int delayacct_on;	/* Delay accounting turned on/off */
>  #endif	/* CONFIG_TASK_DELAY_ACCT */
>  
>  static inline int sched_info_on(void)
> @@ -832,7 +834,6 @@ static inline int sched_info_on(void)
>  #ifdef CONFIG_SCHEDSTATS
>  	return 1;
>  #elif defined(CONFIG_TASK_DELAY_ACCT)
> -	extern int delayacct_on;
>  	return delayacct_on;
>  #else
>  	return 0;
> 
> --
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