pid: remove the child_reaper special case in init/main.c
This patchset is a cleanup and a preparation to unshare the pid namespace.
These prerequisites prepare for Eric's patchset to give a file descriptor
to a namespace and join an existing namespace.
This patch:
It turns out that the existing assignment in copy_process of the
child_reaper can handle the initial assignment of child_reaper we just
need to generalize the test in kernel/fork.c
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/pid.h b/include/linux/pid.h
index 49f1c2f..efceda0 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -141,6 +141,17 @@
}
/*
+ * is_child_reaper returns true if the pid is the init process
+ * of the current namespace. As this one could be checked before
+ * pid_ns->child_reaper is assigned in copy_process, we check
+ * with the pid number.
+ */
+static inline bool is_child_reaper(struct pid *pid)
+{
+ return pid->numbers[pid->level].nr == 1;
+}
+
+/*
* the helpers to get the pid's id seen from different namespaces
*
* pid_nr() : global id, i.e. the id seen from the init namespace;
diff --git a/init/main.c b/init/main.c
index 3627bb3..4a9479e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -787,15 +787,6 @@
* init can run on any cpu.
*/
set_cpus_allowed_ptr(current, cpu_all_mask);
- /*
- * Tell the world that we're going to be the grim
- * reaper of innocent orphaned children.
- *
- * We don't want people to have to make incorrect
- * assumptions about where in the task array this
- * can be found.
- */
- init_pid_ns.child_reaper = current;
cad_pid = task_pid(current);
diff --git a/kernel/fork.c b/kernel/fork.c
index f2b494d..17aed43 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1296,7 +1296,7 @@
tracehook_finish_clone(p, clone_flags, trace);
if (thread_group_leader(p)) {
- if (clone_flags & CLONE_NEWPID)
+ if (is_child_reaper(pid))
p->nsproxy->pid_ns->child_reaper = p;
p->signal->leader_pid = pid;