+/*
+ * the namespaces access rules are:
+ *
+ * 1. only current task is allowed to change tsk->nsproxy pointer or
+ * any pointer on the nsproxy itself
+ *
+ * 2. when accessing (i.e. reading) current task's namespaces - no
+ * precautions should be taken - just dereference the pointers
+ *
+ * 3. the access to other task namespaces is performed like this
+ * rcu_read_lock();
+ * nsproxy = task_nsproxy(tsk);
+ * if (nsproxy != NULL) {
+ * / *
+ * * work with the namespaces here
+ * * e.g. get the reference on one of them
+ * * /
+ * } / *
+ * * NULL task_nsproxy() means that this task is
+ * * almost dead (zombie)
+ * * /
+ * rcu_read_unlock();
+ *
+ */
+
+static inline struct nsproxy *task_nsproxy(struct task_struct *tsk)
+{
+ return rcu_dereference(tsk->nsproxy);
+}
+