include/cgroup: separate {get,put}_cgroup_ns no-op case

When CONFIG_CGROUPS is not selected, {get,put}_cgroup_ns become no-ops
and therefore it is not necessary to compile in the code for changing
the reference count.

When CONFIG_CGROUP is selected, there is no valid case where
either of {get,put}_cgroup_ns() will be called with a NULL argument.

Signed-off-by: Joel Savitz <jsavitz@redhat.com>
Link: https://lore.kernel.org/20250508184930.183040-3-jsavitz@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 28e999f2c64213fa013fa338547b6ddfae0777d0..8da19c3627b0e9b09a3bfd8906de2887f21495b4 100644 (file)
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -785,6 +785,17 @@ struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
                   struct cgroup_namespace *ns);
 
+static inline void get_cgroup_ns(struct cgroup_namespace *ns)
+{
+       refcount_inc(&ns->ns.count);
+}
+
+static inline void put_cgroup_ns(struct cgroup_namespace *ns)
+{
+       if (refcount_dec_and_test(&ns->ns.count))
+               free_cgroup_ns(ns);
+}
+
 #else /* !CONFIG_CGROUPS */
 
 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
@@ -795,19 +806,10 @@ copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
        return old_ns;
 }
 
-#endif /* !CONFIG_CGROUPS */
+static inline void get_cgroup_ns(struct cgroup_namespace *ns) { }
+static inline void put_cgroup_ns(struct cgroup_namespace *ns) { }
 
-static inline void get_cgroup_ns(struct cgroup_namespace *ns)
-{
-       if (ns)
-               refcount_inc(&ns->ns.count);
-}
-
-static inline void put_cgroup_ns(struct cgroup_namespace *ns)
-{
-       if (ns && refcount_dec_and_test(&ns->ns.count))
-               free_cgroup_ns(ns);
-}
+#endif /* !CONFIG_CGROUPS */
 
 #ifdef CONFIG_CGROUPS