ns: add to_<type>_ns() to respective headers

Every namespace type has a container_of(ns, <ns_type>, ns) static inline
function that is currently not exposed in the header. So we have a bunch
of places that open-code it via container_of(). Move it to the headers
so we can use it directly.

Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index bf7613ba412b..5d34c4f0f945 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -30,6 +30,11 @@ struct uts_namespace {
 extern struct uts_namespace init_uts_ns;
 
 #ifdef CONFIG_UTS_NS
+static inline struct uts_namespace *to_uts_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct uts_namespace, ns);
+}
+
 static inline void get_uts_ns(struct uts_namespace *ns)
 {
 	refcount_inc(&ns->ns.count);