sched: Move sched_autogroup_exit() to free_signal_struct()

Per Oleg's suggestion, undo fork failure free/put_signal_struct change,
and move sched_autogroup_exit() to free_signal_struct() instead.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1294222564.8369.6.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/fork.c

@@ -169,15 +169,14 @@ EXPORT_SYMBOL(free_task);
 static inline void free_signal_struct(struct signal_struct *sig)
 {
 	taskstats_tgid_free(sig);
+	sched_autogroup_exit(sig);
 	kmem_cache_free(signal_cachep, sig);
 }
 
 static inline void put_signal_struct(struct signal_struct *sig)
 {
-	if (atomic_dec_and_test(&sig->sigcnt)) {
-		sched_autogroup_exit(sig);
+	if (atomic_dec_and_test(&sig->sigcnt))
 		free_signal_struct(sig);
-	}
 }
 
 void __put_task_struct(struct task_struct *tsk)
@@ -1318,7 +1317,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	}
 bad_fork_cleanup_signal:
 	if (!(clone_flags & CLONE_THREAD))
-		put_signal_struct(p->signal);
+		free_signal_struct(p->signal);
 bad_fork_cleanup_sighand:
 	__cleanup_sighand(p->sighand);
 bad_fork_cleanup_fs: