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, 4 insertions, 4 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index f7a43514ac65..82d8714bbede 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -133,11 +133,11 @@ static bool set_one_prio_perm(struct task_struct *p)
 {
         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 
-        if (pcred->user->user_ns == cred->user->user_ns &&
+        if (pcred->user_ns == cred->user_ns &&
             (pcred->uid  == cred->euid ||
              pcred->euid == cred->euid))
                 return true;
-        if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
+        if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
                 return true;
         return false;
 }
@@ -1498,7 +1498,7 @@ static int check_prlimit_permission(struct task_struct *task)
                 return 0;
 
         tcred = __task_cred(task);
-        if (cred->user->user_ns == tcred->user->user_ns &&
+        if (cred->user_ns == tcred->user_ns &&
             (cred->uid == tcred->euid &&
              cred->uid == tcred->suid &&
              cred->uid == tcred->uid  &&
@@ -1506,7 +1506,7 @@ static int check_prlimit_permission(struct task_struct *task)
              cred->gid == tcred->sgid &&
              cred->gid == tcred->gid))
                 return 0;
-        if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
+        if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
                 return 0;
 
         return -EPERM;