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

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

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 */