[tip:sched/core] sched: Change thread_group_cputime() to use for_each_thread()

[tip-bot for Oleg Nesterov <tipbot@zytor.com>]

Commit-ID:  1e4dda08b4c39b3d8f4a3ee7269d49e0200c8af8
Gitweb:     http://git.kernel.org/tip/1e4dda08b4c39b3d8f4a3ee7269d49e0200c8af8
Author:     Oleg Nesterov <oleg@redhat.com>
AuthorDate: Wed, 13 Aug 2014 21:20:00 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 20 Aug 2014 09:47:18 +0200

sched: Change thread_group_cputime() to use for_each_thread()

Change thread_group_cputime() to use for_each_thread() instead of
buggy while_each_thread(). This also makes the pid_alive() check
unnecessary.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Frank Mayhar <fmayhar@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sanjay Rao <srao@redhat.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140813192000.GA19327@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/cputime.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 72fdf06..3e52836 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -294,18 +294,12 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
 	times->sum_exec_runtime = sig->sum_sched_runtime;
 
 	rcu_read_lock();
-	/* make sure we can trust tsk->thread_group list */
-	if (!likely(pid_alive(tsk)))
-		goto out;
-
-	t = tsk;
-	do {
+	for_each_thread(tsk, t) {
 		task_cputime(t, &utime, &stime);
 		times->utime += utime;
 		times->stime += stime;
 		times->sum_exec_runtime += task_sched_runtime(t);
-	} while_each_thread(tsk, t);
-out:
+	}
 	rcu_read_unlock();
 }