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>
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index ee8d49b..24e0a5a 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -198,7 +198,7 @@
return 0;
rcu_read_lock();
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 &&
@@ -206,7 +206,7 @@
cred->gid == tcred->sgid &&
cred->gid == tcred->gid))
goto ok;
- if (ptrace_has_cap(tcred->user->user_ns, mode))
+ if (ptrace_has_cap(tcred->user_ns, mode))
goto ok;
rcu_read_unlock();
return -EPERM;