[PATCH -mm] introduce tracehook_finish_jctl() helper

[Oleg Nesterov <oleg@redhat.com>]

(textually depends on signals-tracehook_notify_jctl-change.patch)

Introduce the empty inline tracehook_finish_jctl() helper called by
do_signal_stop() after wakeup.

Currently we lack the ability to report this state change.

Also fix the comment, it should be placed before schedule().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---

 include/linux/tracehook.h |    9 +++++++++
 kernel/signal.c           |    2 ++
 2 files changed, 11 insertions(+)

--- __UTRACE/include/linux/tracehook.h~2_FINISH_JCTL	2009-07-29 03:10:10.000000000 +0200
+++ __UTRACE/include/linux/tracehook.h	2009-07-29 03:51:42.000000000 +0200
@@ -521,6 +521,15 @@ static inline int tracehook_notify_jctl(
 	return notify ?: (current->ptrace & PT_PTRACED) ? why : 0;
 }
 
+/**
+ * tracehook_finish_jctl - report about return from job control stop
+ *
+ * This is called by do_signal_stop() after wakeup.
+ */
+static inline void tracehook_finish_jctl(void)
+{
+}
+
 #define DEATH_REAP			-1
 #define DEATH_DELAYED_GROUP_LEADER	-2
 
--- __UTRACE/kernel/signal.c~2_FINISH_JCTL	2009-07-29 03:17:49.000000000 +0200
+++ __UTRACE/kernel/signal.c	2009-07-29 03:57:07.000000000 +0200
@@ -1735,12 +1735,12 @@ static int do_signal_stop(int signr)
 		read_unlock(&tasklist_lock);
 	}
 
+	/* Now we don't run again until woken by SIGCONT or SIGKILL */
 	do {
 		schedule();
 	} while (try_to_freeze());
-	/*
-	 * Now we don't run again until continued.
-	 */
+
+	tracehook_finish_jctl();
 	current->exit_code = 0;
 
 	return 1;