rcu: Stopgap fix for synchronize_rcu_expedited() for TREE_PREEMPT_RCU

[safe/jmp/linux-2.6] / include / linux / tracehook.h

diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index c7aa154..1eb44a9 100644 (file)
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -1,7 +1,7 @@
 /*
  * Tracing hooks
  *
- * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
@@ -143,7 +143,7 @@ static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step)
  *
  * Return %LSM_UNSAFE_* bits applied to an exec because of tracing.
  *
- * Called with task_lock() held on @task.
+ * @task->cred_guard_mutex is held by the caller through the do_execve().
  */
 static inline int tracehook_unsafe_exec(struct task_struct *task)
 {
@@ -259,14 +259,12 @@ static inline void tracehook_finish_clone(struct task_struct *child,
 
 /**
  * tracehook_report_clone - in parent, new child is about to start running
- * @trace:             return value from tracehook_prepare_clone()
  * @regs:              parent's user register state
  * @clone_flags:       flags from parent's system call
  * @pid:               new child's PID in the parent's namespace
  * @child:             new child task
  *
- * Called after a child is set up, but before it has been started
- * running.  @trace is the value returned by tracehook_prepare_clone().
+ * Called after a child is set up, but before it has been started running.
  * This is not a good place to block, because the child has not started
  * yet.  Suspend the child here if desired, and then block in
  * tracehook_report_clone_complete().  This must prevent the child from
@@ -276,13 +274,14 @@ static inline void tracehook_finish_clone(struct task_struct *child,
  *
  * Called with no locks held, but the child cannot run until this returns.
  */
-static inline void tracehook_report_clone(int trace, struct pt_regs *regs,
+static inline void tracehook_report_clone(struct pt_regs *regs,
                                          unsigned long clone_flags,
                                          pid_t pid, struct task_struct *child)
 {
-       if (unlikely(trace) || unlikely(clone_flags & CLONE_PTRACE)) {
+       if (unlikely(task_ptrace(child))) {
                /*
-                * The child starts up with an immediate SIGSTOP.
+                * It doesn't matter who attached/attaching to this
+                * task, the pending SIGSTOP is right in any case.
                 */
                sigaddset(&child->pending.signal, SIGSTOP);
                set_tsk_thread_flag(child, TIF_SIGPENDING);
@@ -464,22 +463,38 @@ static inline int tracehook_get_signal(struct task_struct *task,
 
 /**
  * tracehook_notify_jctl - report about job control stop/continue
- * @notify:            nonzero if this is the last thread in the group to stop
+ * @notify:            zero, %CLD_STOPPED or %CLD_CONTINUED
  * @why:               %CLD_STOPPED or %CLD_CONTINUED
  *
  * This is called when we might call do_notify_parent_cldstop().
- * It's called when about to stop for job control; we are already in
- * %TASK_STOPPED state, about to call schedule().  It's also called when
- * a delayed %CLD_STOPPED or %CLD_CONTINUED report is ready to be made.
  *
- * Return nonzero to generate a %SIGCHLD with @why, which is
- * normal if @notify is nonzero.
+ * @notify is zero if we would not ordinarily send a %SIGCHLD,
+ * or is the %CLD_STOPPED or %CLD_CONTINUED .si_code for %SIGCHLD.
  *
- * Called with no locks held.
+ * @why is %CLD_STOPPED when about to stop for job control;
+ * we are already in %TASK_STOPPED state, about to call schedule().
+ * It might also be that we have just exited (check %PF_EXITING),
+ * but need to report that a group-wide stop is complete.
+ *
+ * @why is %CLD_CONTINUED when waking up after job control stop and
+ * ready to make a delayed @notify report.
+ *
+ * Return the %CLD_* value for %SIGCHLD, or zero to generate no signal.
+ *
+ * Called with the siglock held.
  */
 static inline int tracehook_notify_jctl(int notify, int why)
 {
-       return notify || (current->ptrace & PT_PTRACED);
+       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