[Devel] [PATCH vz10 v5 1/2] ve: Introduce task_pid_ve_nr() helper

[Konstantin Khorenko]

From: Aleksei Oladko <aleksey.oladko at virtuozzo.com>

The new helper returns pid in root pidns of VE.

https://virtuozzo.atlassian.net/browse/VSTOR-119875

Signed-off-by: Aleksei Oladko <aleksey.oladko at virtuozzo.com>
Reviewed-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

Feature: ve: ve generic structures

---
v4: used task_ve guard helpers
v5:
  - ve_ns has been renamed to ve_nsproxy in order not to mess with VE namespace
  - use new, bright and shiny __free(put_ve) attribute
  - added a comment why we don't check ve returned by get_task_ve() for NULL
---
 include/linux/ve.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/linux/ve.h b/include/linux/ve.h
index 0fbc4c45525fc..b01c593dad7b9 100644
--- a/include/linux/ve.h
+++ b/include/linux/ve.h
@@ -21,6 +21,7 @@
 #include <asm/vdso.h>
 #include <linux/time_namespace.h>
 #include <linux/binfmts.h>
+#include <linux/pid.h>
 
 struct nsproxy;
 struct user_namespace;
@@ -202,6 +203,24 @@ static inline struct ve_struct *css_to_ve(struct cgroup_subsys_state *css)
 
 extern struct cgroup_subsys_state *ve_get_init_css(struct ve_struct *ve, int subsys_id);
 
+static inline pid_t task_pid_ve_nr(struct task_struct *tsk)
+{
+	struct nsproxy *ve_nsproxy;
+	struct ve_struct *ve __free(put_ve) = get_task_ve(tsk);
+	pid_t pid;
+
+	rcu_read_lock();
+	/* get_task_ve() always returns non-NULL when CONFIG_VE is enabled */
+	ve_nsproxy = rcu_dereference(ve->ve_nsproxy);
+	if (ve_nsproxy)
+		pid = task_pid_nr_ns(tsk, ve_nsproxy->pid_ns_for_children);
+	else
+		pid = task_pid_nr(tsk);
+	rcu_read_unlock();
+
+	return pid;
+}
+
 static inline struct time_namespace *ve_get_time_ns(struct ve_struct *ve)
 {
 	struct nsproxy *ve_nsproxy;
-- 
2.43.0