4 files changed, 36 insertions, 22 deletions

diff --git a/ipc/namespace.c b/ipc/namespace.c
index 177fa9db391d..3c1e8d3bd7d3 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -149,6 +149,11 @@ void put_ipc_ns(struct ipc_namespace *ns)
 	}
 }
 
+static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct ipc_namespace, ns);
+}
+
 static void *ipcns_get(struct task_struct *task)
 {
 	struct ipc_namespace *ns = NULL;
@@ -160,17 +165,17 @@ static void *ipcns_get(struct task_struct *task)
 		ns = get_ipc_ns(nsproxy->ipc_ns);
 	task_unlock(task);
 
-	return ns;
+	return ns ? &ns->ns : NULL;
 }
 
 static void ipcns_put(void *ns)
 {
-	return put_ipc_ns(ns);
+	return put_ipc_ns(to_ipc_ns(ns));
 }
 
 static int ipcns_install(struct nsproxy *nsproxy, void *new)
 {
-	struct ipc_namespace *ns = new;
+	struct ipc_namespace *ns = to_ipc_ns(new);
 	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
 	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
 		return -EPERM;
@@ -184,9 +189,7 @@ static int ipcns_install(struct nsproxy *nsproxy, void *new)
 
 static unsigned int ipcns_inum(void *vp)
 {
-	struct ipc_namespace *ns = vp;
-
-	return ns->ns.inum;
+	return ((struct ns_common *)vp)->inum;
 }
 
 const struct proc_ns_operations ipcns_operations = {
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 99e27e5bf906..dd961ad86fbd 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -313,6 +313,11 @@ int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
 	return 0;
 }
 
+static inline struct pid_namespace *to_pid_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct pid_namespace, ns);
+}
+
 static void *pidns_get(struct task_struct *task)
 {
 	struct pid_namespace *ns;
@@ -323,18 +328,18 @@ static void *pidns_get(struct task_struct *task)
 		get_pid_ns(ns);
 	rcu_read_unlock();
 
-	return ns;
+	return ns ? &ns->ns : NULL;
 }
 
 static void pidns_put(void *ns)
 {
-	put_pid_ns(ns);
+	put_pid_ns(to_pid_ns(ns));
 }
 
 static int pidns_install(struct nsproxy *nsproxy, void *ns)
 {
 	struct pid_namespace *active = task_active_pid_ns(current);
-	struct pid_namespace *ancestor, *new = ns;
+	struct pid_namespace *ancestor, *new = to_pid_ns(ns);
 
 	if (!ns_capable(new->user_ns, CAP_SYS_ADMIN) ||
 	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
@@ -364,8 +369,7 @@ static int pidns_install(struct nsproxy *nsproxy, void *ns)
 
 static unsigned int pidns_inum(void *ns)
 {
-	struct pid_namespace *pid_ns = ns;
-	return pid_ns->ns.inum;
+	return ((struct ns_common *)ns)->inum;
 }
 
 const struct proc_ns_operations pidns_operations = {
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index fde584082673..1ab2209228ff 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -841,6 +841,11 @@ static bool new_idmap_permitted(const struct file *file,
 	return false;
 }
 
+static inline struct user_namespace *to_user_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct user_namespace, ns);
+}
+
 static void *userns_get(struct task_struct *task)
 {
 	struct user_namespace *user_ns;
@@ -849,17 +854,17 @@ static void *userns_get(struct task_struct *task)
 	user_ns = get_user_ns(__task_cred(task)->user_ns);
 	rcu_read_unlock();
 
-	return user_ns;
+	return user_ns ? &user_ns->ns : NULL;
 }
 
 static void userns_put(void *ns)
 {
-	put_user_ns(ns);
+	put_user_ns(to_user_ns(ns));
 }
 
 static int userns_install(struct nsproxy *nsproxy, void *ns)
 {
-	struct user_namespace *user_ns = ns;
+	struct user_namespace *user_ns = to_user_ns(ns);
 	struct cred *cred;
 
 	/* Don't allow gaining capabilities by reentering
@@ -890,8 +895,7 @@ static int userns_install(struct nsproxy *nsproxy, void *ns)
 
 static unsigned int userns_inum(void *ns)
 {
-	struct user_namespace *user_ns = ns;
-	return user_ns->ns.inum;
+	return ((struct ns_common *)ns)->inum;
 }
 
 const struct proc_ns_operations userns_operations = {
diff --git a/kernel/utsname.c b/kernel/utsname.c
index b1cd00b828f2..1917f74be8ec 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -88,6 +88,11 @@ void free_uts_ns(struct kref *kref)
 	kfree(ns);
 }
 
+static inline struct uts_namespace *to_uts_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct uts_namespace, ns);
+}
+
 static void *utsns_get(struct task_struct *task)
 {
 	struct uts_namespace *ns = NULL;
@@ -101,17 +106,17 @@ static void *utsns_get(struct task_struct *task)
 	}
 	task_unlock(task);
 
-	return ns;
+	return ns ? &ns->ns : NULL;
 }
 
 static void utsns_put(void *ns)
 {
-	put_uts_ns(ns);
+	put_uts_ns(to_uts_ns(ns));
 }
 
 static int utsns_install(struct nsproxy *nsproxy, void *new)
 {
-	struct uts_namespace *ns = new;
+	struct uts_namespace *ns = to_uts_ns(new);
 
 	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
 	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
@@ -125,9 +130,7 @@ static int utsns_install(struct nsproxy *nsproxy, void *new)
 
 static unsigned int utsns_inum(void *vp)
 {
-	struct uts_namespace *ns = vp;
-
-	return ns->ns.inum;
+	return ((struct ns_common *)vp)->inum;
 }
 
 const struct proc_ns_operations utsns_operations = {