[tip/core/rcu,05/55] rcu: Move rcu_head definition to types.h

Take a first step towards untangling Linux kernel header files by
placing the struct rcu_head definition into include/linux/types.h
and including include/linux/types.h in include/linux/rcupdate.h
where struct rcu_head used to be defined.  The actual inclusion point
for include/linux/types.h is with the rest of the #include directives
rather than at the point where struct rcu_head used to be defined,
as suggested by Mathieu Desnoyers.

Once this is in place, then header files that need only rcu_head
can include types.h rather than rcupdate.h.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 include/linux/rcupdate.h |   11 +----------
 include/linux/types.h    |   10 ++++++++++
 2 files changed, 11 insertions(+), 10 deletions(-)

On 11-09-06 01:59 PM, Paul E. McKenney wrote:
> Take a first step towards untangling Linux kernel header files by
> placing the struct rcu_head definition into include/linux/types.h
> and including include/linux/types.h in include/linux/rcupdate.h
> where struct rcu_head used to be defined.  The actual inclusion point
> for include/linux/types.h is with the rest of the #include directives
> rather than at the point where struct rcu_head used to be defined,
> as suggested by Mathieu Desnoyers.
> 
> Once this is in place, then header files that need only rcu_head
> can include types.h rather than rcupdate.h.

Good to see more of this untangle work taking place.

The only comment I have is whether there is any sort of implicit
categorization in place for what is appropriate for types.h.

At the moment it seems to only contain really core primary types
(and the list/hlist structs which are almost core types...)

Are there any other alternative places - does linux/kernel.h make
more sense?

Paul.

> 
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> ---
>  include/linux/rcupdate.h |   11 +----------
>  include/linux/types.h    |   10 ++++++++++
>  2 files changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> index 8be0433..2516555 100644
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -33,6 +33,7 @@
>  #ifndef __LINUX_RCUPDATE_H
>  #define __LINUX_RCUPDATE_H
>  
> +#include <linux/types.h>
>  #include <linux/cache.h>
>  #include <linux/spinlock.h>
>  #include <linux/threads.h>
> @@ -64,16 +65,6 @@ static inline void rcutorture_record_progress(unsigned long vernum)
>  #define ULONG_CMP_GE(a, b)	(ULONG_MAX / 2 >= (a) - (b))
>  #define ULONG_CMP_LT(a, b)	(ULONG_MAX / 2 < (a) - (b))
>  
> -/**
> - * struct rcu_head - callback structure for use with RCU
> - * @next: next update requests in a list
> - * @func: actual update function to call after the grace period.
> - */
> -struct rcu_head {
> -	struct rcu_head *next;
> -	void (*func)(struct rcu_head *head);
> -};
> -
>  /* Exported common interfaces */
>  extern void call_rcu_sched(struct rcu_head *head,
>  			   void (*func)(struct rcu_head *rcu));
> diff --git a/include/linux/types.h b/include/linux/types.h
> index 176da8c..57a9723 100644
> --- a/include/linux/types.h
> +++ b/include/linux/types.h
> @@ -238,6 +238,16 @@ struct ustat {
>  	char			f_fpack[6];
>  };
>  
> +/**
> + * struct rcu_head - callback structure for use with RCU
> + * @next: next update requests in a list
> + * @func: actual update function to call after the grace period.
> + */
> +struct rcu_head {
> +	struct rcu_head *next;
> +	void (*func)(struct rcu_head *head);
> +};
> +
>  #endif	/* __KERNEL__ */
>  #endif /*  __ASSEMBLY__ */
>  #endif /* _LINUX_TYPES_H */

On Wed, Sep 07, 2011 at 02:31:51PM -0400, Paul Gortmaker wrote:
> On 11-09-06 01:59 PM, Paul E. McKenney wrote:
> > Take a first step towards untangling Linux kernel header files by
> > placing the struct rcu_head definition into include/linux/types.h
> > and including include/linux/types.h in include/linux/rcupdate.h
> > where struct rcu_head used to be defined.  The actual inclusion point
> > for include/linux/types.h is with the rest of the #include directives
> > rather than at the point where struct rcu_head used to be defined,
> > as suggested by Mathieu Desnoyers.
> > 
> > Once this is in place, then header files that need only rcu_head
> > can include types.h rather than rcupdate.h.
> 
> Good to see more of this untangle work taking place.
> 
> The only comment I have is whether there is any sort of implicit
> categorization in place for what is appropriate for types.h.
> 
> At the moment it seems to only contain really core primary types
> (and the list/hlist structs which are almost core types...)

Actually, it was the presence of the list/hlist structs that convinced
me that types.h was a good place for rcu_head.

							Thanx, Paul

> Are there any other alternative places - does linux/kernel.h make
> more sense?
> 
> Paul.
> 
> > 
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
> > Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> > ---
> >  include/linux/rcupdate.h |   11 +----------
> >  include/linux/types.h    |   10 ++++++++++
> >  2 files changed, 11 insertions(+), 10 deletions(-)
> > 
> > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> > index 8be0433..2516555 100644
> > --- a/include/linux/rcupdate.h
> > +++ b/include/linux/rcupdate.h
> > @@ -33,6 +33,7 @@
> >  #ifndef __LINUX_RCUPDATE_H
> >  #define __LINUX_RCUPDATE_H
> >  
> > +#include <linux/types.h>
> >  #include <linux/cache.h>
> >  #include <linux/spinlock.h>
> >  #include <linux/threads.h>
> > @@ -64,16 +65,6 @@ static inline void rcutorture_record_progress(unsigned long vernum)
> >  #define ULONG_CMP_GE(a, b)	(ULONG_MAX / 2 >= (a) - (b))
> >  #define ULONG_CMP_LT(a, b)	(ULONG_MAX / 2 < (a) - (b))
> >  
> > -/**
> > - * struct rcu_head - callback structure for use with RCU
> > - * @next: next update requests in a list
> > - * @func: actual update function to call after the grace period.
> > - */
> > -struct rcu_head {
> > -	struct rcu_head *next;
> > -	void (*func)(struct rcu_head *head);
> > -};
> > -
> >  /* Exported common interfaces */
> >  extern void call_rcu_sched(struct rcu_head *head,
> >  			   void (*func)(struct rcu_head *rcu));
> > diff --git a/include/linux/types.h b/include/linux/types.h
> > index 176da8c..57a9723 100644
> > --- a/include/linux/types.h
> > +++ b/include/linux/types.h
> > @@ -238,6 +238,16 @@ struct ustat {
> >  	char			f_fpack[6];
> >  };
> >  
> > +/**
> > + * struct rcu_head - callback structure for use with RCU
> > + * @next: next update requests in a list
> > + * @func: actual update function to call after the grace period.
> > + */
> > +struct rcu_head {
> > +	struct rcu_head *next;
> > +	void (*func)(struct rcu_head *head);
> > +};
> > +
> >  #endif	/* __KERNEL__ */
> >  #endif /*  __ASSEMBLY__ */
> >  #endif /* _LINUX_TYPES_H */