[PATCH 05/12] pid: get pid_t of task in init_pid_ns correctly

[Richard Guy Briggs]

Added the functions
        task_pid_nr_init_ns()
        task_tgid_nr_init_ns()
to avoid the use of the error-prone duplicity of task->pid and task->tgid,
avoid changing the existing usage of task_pid_nr() and task_tgid_nr() while it
gets converted away from task->pid and task->tgid, and provide a clear
abstraction of the frequently used init_pid_ns in task_pid_nr_ns() and
task_tgid_nr_ns().
Also added pid_nr_init_ns() to explicitly use init_pid_ns.

(informed by ebiederman's 3a2e8c59)
Cc: Eric W. Biederman <ebiederm at xmission.com>
Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
---
 include/linux/pid.h   |    6 ++++++
 include/linux/sched.h |   10 ++++++++++
 2 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/include/linux/pid.h b/include/linux/pid.h
index 23705a5..051e134 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -172,6 +172,12 @@ 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);
 
+static inline pid_t pid_nr_init_ns(struct pid *pid)
+{
+	return pid_nr_ns(pid, &init_pid_ns);
+}
+
+
 #define do_each_pid_task(pid, type, task)				\
 	do {								\
 		if ((pid) != NULL)					\
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ec04090..9651d95 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1482,6 +1482,11 @@ static inline pid_t task_pid_nr_ns(struct task_struct *tsk,
 	return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
 }
 
+static inline pid_t task_pid_nr_init_ns(struct task_struct *tsk)
+{
+	return task_pid_nr_ns(tsk, &init_pid_ns);
+}
+
 static inline pid_t task_pid_vnr(struct task_struct *tsk)
 {
 	return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
@@ -1495,6 +1500,11 @@ static inline pid_t task_tgid_nr(struct task_struct *tsk)
 
 pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns);
 
+static inline pid_t task_tgid_nr_init_ns(struct task_struct *tsk)
+{
+	return task_tgid_nr_ns(tsk, &init_pid_ns);
+}
+
 static inline pid_t task_tgid_vnr(struct task_struct *tsk)
 {
 	return pid_vnr(task_tgid(tsk));
-- 
1.7.1