ptrace: cleanup ptrace_init_task()->ptrace_link() path

No functional changes.

ptrace_init_task() looks confusing, as if we always auto-attach when "bool
ptrace" argument is true, while in fact we attach only if current is
traced.

Make the code more explicit and kill now unused ptrace_link().

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

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 7456d7d..1951805 100644 (file)
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -105,12 +105,7 @@ static inline int ptrace_reparented(struct task_struct *child)
 {
        return child->real_parent != child->parent;
 }
-static inline void ptrace_link(struct task_struct *child,
-                              struct task_struct *new_parent)
-{
-       if (unlikely(child->ptrace))
-               __ptrace_link(child, new_parent);
-}
+
 static inline void ptrace_unlink(struct task_struct *child)
 {
        if (unlikely(child->ptrace))
@@ -169,9 +164,9 @@ static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
        INIT_LIST_HEAD(&child->ptraced);
        child->parent = child->real_parent;
        child->ptrace = 0;
-       if (unlikely(ptrace)) {
+       if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) {
                child->ptrace = current->ptrace;
-               ptrace_link(child, current->parent);
+               __ptrace_link(child, current->parent);
        }
 }