Merge branch 'linus' into release

1 files changed, 20 insertions, 2 deletions

diff --git a/include/linux/pid.h b/include/linux/pid.h
index d7e98ff8021e..49f1c2f66e95 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -123,6 +123,24 @@ extern struct pid *alloc_pid(struct pid_namespace *ns);
 extern void free_pid(struct pid *pid);
 
 /*
+ * ns_of_pid() returns the pid namespace in which the specified pid was
+ * allocated.
+ *
+ * NOTE:
+ *      ns_of_pid() is expected to be called for a process (task) that has
+ *      an attached 'struct pid' (see attach_pid(), detach_pid()) i.e @pid
+ *      is expected to be non-NULL. If @pid is NULL, caller should handle
+ *      the resulting NULL pid-ns.
+ */
+static inline struct pid_namespace *ns_of_pid(struct pid *pid)
+{
+        struct pid_namespace *ns = NULL;
+        if (pid)
+                ns = pid->numbers[pid->level].ns;
+        return ns;
+}
+
+/*
  * 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;
@@ -147,9 +165,9 @@ pid_t pid_vnr(struct pid *pid);
 #define do_each_pid_task(pid, type, task)                               \
         do {                                                            \
                 struct hlist_node *pos___;                              \
-                if (pid != NULL)                                        \
+                if ((pid) != NULL)                                      \
                         hlist_for_each_entry_rcu((task), pos___,        \
-                                &pid->tasks[type], pids[type].node) {
+                                &(pid)->tasks[type], pids[type].node) {
 
                         /*
                          * Both old and new leaders may be attached to