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Commit d387cae0 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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[PATCH] pid: simplify pid iterators 



I think it is hardly possible to read the current do_each_task_pid().  The
new version is much simpler and makes the code smaller.

Only the do_each_task_pid change is tested, the do_each_pid_task isn't.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c88be3eb

include/linux/pid.h

+23 −36
Original line number Diff line number Diff line
@@ -102,42 +102,29 @@ static inline pid_t pid_nr(struct pid *pid) 
	return nr;

}



#define pid_next(task, type)					\

	((task)->pids[(type)].node.next)



#define pid_next_task(task, type) 				\

	hlist_entry(pid_next(task, type), struct task_struct,	\

			pids[(type)].node)





/* We could use hlist_for_each_entry_rcu here but it takes more arguments

 * than the do_each_task_pid/while_each_task_pid.  So we roll our own

 * to preserve the existing interface.

 */

#define do_each_task_pid(who, type, task)					\

	if ((task = find_task_by_pid_type(type, who))) {		\

		prefetch(pid_next(task, type));				\

		do {

	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 (pid_next(task, type) &&  ({			\

				task = pid_next_task(task, type);	\

				rcu_dereference(task);			\

				prefetch(pid_next(task, type));		\

				1; }) );				\

	}

			}							\

	} while (0)





#define do_each_pid_task(pid, type, task)					\

	if ((task = pid_task(pid, type))) {				\

		prefetch(pid_next(task, type));				\

		do {

	do {									\

		struct hlist_node *pos___;					\

		if (pid != NULL)						\

			hlist_for_each_entry_rcu((task), pos___,		\

				&pid->tasks[type], pids[type].node) {



#define while_each_pid_task(pid, type, task)					\

		} while (pid_next(task, type) &&  ({			\

				task = pid_next_task(task, type);	\

				rcu_dereference(task);			\

				prefetch(pid_next(task, type));		\

				1; }) );				\

	}

			}							\

	} while (0)



#endif /* _LINUX_PID_H */