userns: Use cred->user_ns instead of cred->user->user_ns

Optimize performance and prepare for the removal of the user_ns reference
from user_struct.  Remove the slow long walk through cred->user->user_ns and
instead go straight to cred->user_ns.

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

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 17afcaf582d0..e2c5d84f2dac 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -767,14 +767,14 @@ static int kill_ok_by_cred(struct task_struct *t)
         const struct cred *cred = current_cred();
         const struct cred *tcred = __task_cred(t);
 
-        if (cred->user->user_ns == tcred->user->user_ns &&
+        if (cred->user_ns == tcred->user_ns &&
             (cred->euid == tcred->suid ||
              cred->euid == tcred->uid ||
              cred->uid  == tcred->suid ||
              cred->uid  == tcred->uid))
                 return 1;
 
-        if (ns_capable(tcred->user->user_ns, CAP_KILL))
+        if (ns_capable(tcred->user_ns, CAP_KILL))
                 return 1;
 
         return 0;