[Devel] [PATCH vz10] Revert "ve: Replace 0 ppid with 1 (workaround for bad utils)"

[Konstantin Khorenko]

This reverts commit b6a803bdf66bf3da211704060a8f263706c2a364.

We won't support so ancient utils which are not ready for getting 0 as a
parent PID which actually is a normal situation and means that the
parent process is from an outer pidns and is not visible in the
current pidns.

https://virtuozzo.atlassian.net/browse/VSTOR-139436
Feature: procfs: virtualization and visibility configuration
Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
 fs/proc/array.c     |  5 +++--
 include/linux/pid.h |  1 -
 kernel/pid.c        | 12 ------------
 kernel/sys.c        |  2 +-
 4 files changed, 4 insertions(+), 16 deletions(-)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 80b882fe4832..0ff32bee5c50 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -171,7 +171,8 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
 	unsigned int max_fds = 0;
 
 	rcu_read_lock();
-	ppid = pid_alive(p) ? ve_task_ppid_nr_ns(p, ns) : 0;
+	ppid = pid_alive(p) ?
+		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
 
 	tracer = ptrace_parent(p);
 	if (tracer)
@@ -551,7 +552,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 		}
 
 		sid = task_session_nr_ns(task, ns);
-		ppid = ve_task_ppid_nr_ns(task, ns);
+		ppid = task_ppid_nr_ns(task, ns);
 		pgid = task_pgrp_nr_ns(task, ns);
 
 		unlock_task_sighand(task, &flags);
diff --git a/include/linux/pid.h b/include/linux/pid.h
index 04f983d477ff..34ef8e692fee 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -184,7 +184,6 @@ static inline pid_t pid_nr(struct pid *pid)
 
 pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns);
 pid_t pid_vnr(struct pid *pid);
-pid_t ve_task_ppid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns);
 
 #define do_each_pid_task(pid, type, task)				\
 	do {								\
diff --git a/kernel/pid.c b/kernel/pid.c
index c95e572efd7d..350ca2fbff5c 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -517,18 +517,6 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
 }
 EXPORT_SYMBOL(__task_pid_nr_ns);
 
-pid_t ve_task_ppid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
-{
-	pid_t ppid;
-	rcu_read_lock();
-	ppid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns);
-	rcu_read_unlock();
-	/* It's dirty hack. Some old utils don't work if ppid is zero*/
-	if (ppid == 0 && ns->child_reaper != tsk)
-		ppid = 1;
-	return ppid;
-}
-
 struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
 {
 	return ns_of_pid(task_pid(tsk));
diff --git a/kernel/sys.c b/kernel/sys.c
index 33b05af556fa..80f8b9eb17c3 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -990,7 +990,7 @@ SYSCALL_DEFINE0(getppid)
 	int pid;
 
 	rcu_read_lock();
-	pid = ve_task_ppid_nr_ns(current, task_active_pid_ns(current));
+	pid = task_tgid_vnr(rcu_dereference(current->real_parent));
 	rcu_read_unlock();
 
 	return pid;
-- 
2.47.1