userns: Add an explicit reference to the parent user namespace

I am about to remove the struct user_namespace reference from struct user_struct.
So keep an explicit track of the parent user namespace.

Take advantage of this new reference and replace instances of user_ns->creator->user_ns
with user_ns->parent.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/security/commoncap.c b/security/commoncap.c
index 8b3e10e2eac7..435d074853f3 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -92,7 +92,7 @@ int cap_capable(const struct cred *cred, struct user_namespace *targ_ns,
                  *If you have a capability in a parent user ns, then you have
                  * it over all children user namespaces as well.
                  */
-                targ_ns = targ_ns->creator->user_ns;
+                targ_ns = targ_ns->parent;
         }
 
         /* We never get here */