use __set_task_state() for TRACED/STOPPED tasks
Oleg Nesterov [Wed, 6 Feb 2008 09:36:13 +0000 (01:36 -0800)]
1. It is much easier to grep for ->state change if __set_task_state() is used
   instead of the direct assignment.

2. ptrace_stop() and handle_group_stop() use set_task_state() which adds the
   unneeded mb() (btw even if we use mb() it is still possible that do_wait()
   sees the new ->state but not ->exit_code, but this is ok).

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/fork.c
kernel/ptrace.c
kernel/signal.c

index 2b55b74..8adfe5d 100644 (file)
@@ -1510,7 +1510,7 @@ long do_fork(unsigned long clone_flags,
                if (!(clone_flags & CLONE_STOPPED))
                        wake_up_new_task(p, clone_flags);
                else
-                       p->state = TASK_STOPPED;
+                       __set_task_state(p, TASK_STOPPED);
 
                if (unlikely (trace)) {
                        current->ptrace_message = nr;
index b0d4ab4..74730e0 100644 (file)
@@ -53,7 +53,7 @@ void ptrace_untrace(struct task_struct *child)
        spin_lock(&child->sighand->siglock);
        if (task_is_traced(child)) {
                if (child->signal->flags & SIGNAL_STOP_STOPPED) {
-                       child->state = TASK_STOPPED;
+                       __set_task_state(child, TASK_STOPPED);
                } else {
                        signal_wake_up(child, 1);
                }
@@ -103,18 +103,16 @@ int ptrace_check_attach(struct task_struct *child, int kill)
            && child->signal != NULL) {
                ret = 0;
                spin_lock_irq(&child->sighand->siglock);
-               if (task_is_stopped(child)) {
+               if (task_is_stopped(child))
                        child->state = TASK_TRACED;
-               } else if (!task_is_traced(child) && !kill) {
+               else if (!task_is_traced(child) && !kill)
                        ret = -ESRCH;
-               }
                spin_unlock_irq(&child->sighand->siglock);
        }
        read_unlock(&tasklist_lock);
 
-       if (!ret && !kill) {
+       if (!ret && !kill)
                wait_task_inactive(child);
-       }
 
        /* All systems go.. */
        return ret;
index 6a5f97c..e469715 100644 (file)
@@ -1601,7 +1601,7 @@ static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info)
        current->exit_code = exit_code;
 
        /* Let the debugger run.  */
-       set_current_state(TASK_TRACED);
+       __set_current_state(TASK_TRACED);
        spin_unlock_irq(&current->sighand->siglock);
        try_to_freeze();
        read_lock(&tasklist_lock);