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>

6 files changed, 12 insertions, 12 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index ee8d49b9c309..24e0a5a94824 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -198,7 +198,7 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 		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 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 	     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;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4603b9d8f30a..96bff855b866 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4042,7 +4042,7 @@ static bool check_same_owner(struct task_struct *p)
 
 	rcu_read_lock();
 	pcred = __task_cred(p);
-	if (cred->user->user_ns == pcred->user->user_ns)
+	if (cred->user_ns == pcred->user_ns)
 		match = (cred->euid == pcred->euid ||
 			 cred->euid == pcred->uid);
 	else
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;
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;
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 3b906e98b1db..f084083a0fd3 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -90,7 +90,7 @@ uid_t user_ns_map_uid(struct user_namespace *to, const struct cred *cred, uid_t
 {
 	struct user_namespace *tmp;
 
-	if (likely(to == cred->user->user_ns))
+	if (likely(to == cred->user_ns))
 		return uid;
 
 
@@ -112,7 +112,7 @@ gid_t user_ns_map_gid(struct user_namespace *to, const struct cred *cred, gid_t
 {
 	struct user_namespace *tmp;
 
-	if (likely(to == cred->user->user_ns))
+	if (likely(to == cred->user_ns))
 		return gid;
 
 	/* Is cred->user the creator of the target user_ns
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 405caf91aad5..679d97a5d3fd 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -43,7 +43,7 @@ static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
 
 	down_read(&uts_sem);
 	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
-	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user_ns));
 	up_read(&uts_sem);
 	return ns;
 }