ns: drop custom reference count initialization for initial namespaces

Initial namespaces don't modify their reference count anymore.
They remain fixed at one so drop the custom refcount initializations.

Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-16-e8a9264e0fb9@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

fs/namespace.c

@@ -5986,7 +5986,7 @@ SYSCALL_DEFINE4(listmount, const struct mnt_id_req __user *, req,
 }
 
 struct mnt_namespace init_mnt_ns = {
-	.ns		= NS_COMMON_INIT(init_mnt_ns, 1),
+	.ns		= NS_COMMON_INIT(init_mnt_ns),
 	.user_ns	= &init_user_ns,
 	.passive	= REFCOUNT_INIT(1),
 	.mounts		= RB_ROOT,

include/linux/ns_common.h

@@ -26,14 +26,14 @@ static __always_inline bool is_ns_init_id(const struct ns_common *ns)
 	return ns->ns_id <= NS_LAST_INIT_ID;
 }
 
-#define NS_COMMON_INIT(nsname, refs)									\
+#define NS_COMMON_INIT(nsname)										\
 {													\
 	.ns_type			= ns_common_type(&nsname),					\
 	.ns_id				= ns_init_id(&nsname),						\
 	.inum				= ns_init_inum(&nsname),					\
 	.ops				= to_ns_operations(&nsname),					\
 	.stashed			= NULL,								\
-	.__ns_ref			= REFCOUNT_INIT(refs),						\
+	.__ns_ref			= REFCOUNT_INIT(1),						\
 	.__ns_ref_active		= ATOMIC_INIT(1),						\
 	.ns_unified_node.ns_list_entry	= LIST_HEAD_INIT(nsname.ns.ns_unified_node.ns_list_entry),	\
 	.ns_tree_node.ns_list_entry	= LIST_HEAD_INIT(nsname.ns.ns_tree_node.ns_list_entry),		\

init/version-timestamp.c

@@ -8,7 +8,7 @@
 #include <linux/utsname.h>
 
 struct uts_namespace init_uts_ns = {
-	.ns = NS_COMMON_INIT(init_uts_ns, 2),
+	.ns = NS_COMMON_INIT(init_uts_ns),
 	.name = {
 		.sysname	= UTS_SYSNAME,
 		.nodename	= UTS_NODENAME,

ipc/msgutil.c

@@ -27,7 +27,7 @@ DEFINE_SPINLOCK(mq_lock);
  * and not CONFIG_IPC_NS.
  */
 struct ipc_namespace init_ipc_ns = {
-	.ns = NS_COMMON_INIT(init_ipc_ns, 1),
+	.ns = NS_COMMON_INIT(init_ipc_ns),
 	.user_ns = &init_user_ns,
 };
 

kernel/cgroup/cgroup.c

@@ -250,7 +250,7 @@ bool cgroup_enable_per_threadgroup_rwsem __read_mostly;
 
 /* cgroup namespace for init task */
 struct cgroup_namespace init_cgroup_ns = {
-	.ns		= NS_COMMON_INIT(init_cgroup_ns, 2),
+	.ns		= NS_COMMON_INIT(init_cgroup_ns),
 	.user_ns	= &init_user_ns,
 	.root_cset	= &init_css_set,
 };

kernel/pid.c

@@ -71,7 +71,7 @@ static int pid_max_max = PID_MAX_LIMIT;
  * the scheme scales to up to 4 million PIDs, runtime.
  */
 struct pid_namespace init_pid_ns = {
-	.ns = NS_COMMON_INIT(init_pid_ns, 2),
+	.ns = NS_COMMON_INIT(init_pid_ns),
 	.idr = IDR_INIT(init_pid_ns.idr),
 	.pid_allocated = PIDNS_ADDING,
 	.level = 0,

kernel/time/namespace.c

@@ -478,7 +478,7 @@ const struct proc_ns_operations timens_for_children_operations = {
 };
 
 struct time_namespace init_time_ns = {
-	.ns		= NS_COMMON_INIT(init_time_ns, 3),
+	.ns		= NS_COMMON_INIT(init_time_ns),
 	.user_ns	= &init_user_ns,
 	.frozen_offsets	= true,
 };

kernel/user.c

@@ -35,7 +35,7 @@ EXPORT_SYMBOL_GPL(init_binfmt_misc);
  * and 1 for... ?
  */
 struct user_namespace init_user_ns = {
-	.ns = NS_COMMON_INIT(init_user_ns, 3),
+	.ns = NS_COMMON_INIT(init_user_ns),
 	.uid_map = {
 		{
 			.extent[0] = {