ptrace: introduce ptrace_reparented() helper

Add another trivial helper for the sake of grep.  It also auto-documents the
fact that ->parent != real_parent implies ->ptrace.

No functional changes.

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>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index ebe0c17039cf..f98501ba557e 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -98,6 +98,10 @@ extern void ptrace_untrace(struct task_struct *child);
 extern int ptrace_may_attach(struct task_struct *task);
 extern int __ptrace_may_attach(struct task_struct *task);
 
+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)
 {