Re: [PATCH] pids: simplify do_each_task_pid/while_each_task_pid

[Oleg Nesterov <oleg@tv-sign.ru>]

On 04/13, Christoph Hellwig wrote:
>
> On Thu, Apr 13, 2006 at 08:37:27PM +0400, Oleg Nesterov wrote:
> > +#define do_each_task_pid(who, type, task)					\
> > +	do {									\
> > +		struct hlist_node *pos___;					\
> > +		struct pid *pid___ = find_pid(who);				\
> > +		if (pid___ != NULL)						\
> > +			hlist_for_each_entry_rcu((task), pos___,		\
> > +				&pid___->tasks[type], pids[type].node) {
> > +
> > +#define while_each_task_pid(who, type, task)					\
> > +			}							\
> > +	} while (0)
> 
> This is prtty ugly.  Can't we just have a
> 
> #define for_each_task_pid(task, pid, type, pos) \
> 	hlist_for_each_entry_rcu((task), (pos),  \
> 		(&(pid))->tasks[type], pids[type].node) {
> 
> and move the find_pid to the caller?  That would make the code a whole lot
> more readable.

Then the caller should check find_pid() doesn't return NULL. But yes,
we can hide this check inside for_each_task_pid().

But what about current users of do_each_task_pid ? We can't just remove
these macros.

Oleg.