kill my_ptrace_child()

Now that my_ptrace_child() is trivial we can use the "p->ptrace & PT_PTRACED"
inline and simplify the corresponding logic in do_wait: we can't find the
child in TASK_TRACED state without PT_PTRACED flag set, ptrace_untrace()
either sets TASK_STOPPED or wakes up the tracee.

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

1 files changed, 3 insertions, 20 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 1f2c15297f2d..b5ff2b121093 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1511,12 +1511,6 @@ static int wait_task_continued(struct task_struct *p, int noreap,
         return retval;
 }
 
-
-static inline int my_ptrace_child(struct task_struct *p)
-{
-        return p->ptrace & PT_PTRACED;
-}
-
 static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
                     int __user *stat_addr, struct rusage __user *ru)
 {
@@ -1555,22 +1549,11 @@ repeat:
                                 /*
                                  * It's stopped now, so it might later
                                  * continue, exit, or stop again.
-                                 *
-                                 * When we hit the race with PTRACE_ATTACH, we
-                                 * will not report this child.  But the race
-                                 * means it has not yet been moved to our
-                                 * ptrace_children list, so we need to set the
-                                 * flag here to avoid a spurious ECHILD when
-                                 * the race happens with the only child.
                                  */
                                 flag = 1;
-
-                                if (!my_ptrace_child(p)) {
-                                        if (task_is_traced(p))
-                                                continue;
-                                        if (!(options & WUNTRACED))
-                                                continue;
-                                }
+                                if (!(p->ptrace & PT_PTRACED) &&
+                                    !(options & WUNTRACED))
+                                        continue;
 
                                 retval = wait_task_stopped(p, ret == 2,
                                                 (options & WNOWAIT), infop,