[PATCH 2/3] ns: simplify ns_common_init() further
From: Christian Brauner <brauner@kernel.org>
Date: 2025-09-22 12:42:56
Also in:
cgroups, linux-fsdevel, lkml
Subsystem:
control group (cgroup), filesystems (vfs and infrastructure), namespaces:, networking [general], posix clocks and timers, the rest · Maintainers:
Tejun Heo, Johannes Weiner, Michal Koutný, Alexander Viro, Christian Brauner, Christian Brauner, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Anna-Maria Behnsen, Frederic Weisbecker, Thomas Gleixner, Linus Torvalds
Simply derive the ns operations from the namespace type. Signed-off-by: Christian Brauner <brauner@kernel.org> --- fs/namespace.c | 4 ++-- include/linux/ns_common.h | 30 ++++++++++++++++++++++++++---- ipc/namespace.c | 2 +- kernel/cgroup/namespace.c | 2 +- kernel/pid_namespace.c | 2 +- kernel/time/namespace.c | 2 +- kernel/user_namespace.c | 2 +- kernel/utsname.c | 2 +- net/core/net_namespace.c | 9 +-------- 9 files changed, 35 insertions(+), 20 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 271cd6294c8a..d65917ec5544 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c@@ -4104,9 +4104,9 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool a } if (anon) - ret = ns_common_init_inum(new_ns, &mntns_operations, MNT_NS_ANON_INO); + ret = ns_common_init_inum(new_ns, MNT_NS_ANON_INO); else - ret = ns_common_init(new_ns, &mntns_operations); + ret = ns_common_init(new_ns); if (ret) { kfree(new_ns); dec_mnt_namespaces(ucounts);
diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
index aea8528d799a..56492cd9ff8d 100644
--- a/include/linux/ns_common.h
+++ b/include/linux/ns_common.h@@ -25,6 +25,17 @@ extern struct time_namespace init_time_ns; extern struct user_namespace init_user_ns; extern struct uts_namespace init_uts_ns; +extern const struct proc_ns_operations netns_operations; +extern const struct proc_ns_operations utsns_operations; +extern const struct proc_ns_operations ipcns_operations; +extern const struct proc_ns_operations pidns_operations; +extern const struct proc_ns_operations pidns_for_children_operations; +extern const struct proc_ns_operations userns_operations; +extern const struct proc_ns_operations mntns_operations; +extern const struct proc_ns_operations cgroupns_operations; +extern const struct proc_ns_operations timens_operations; +extern const struct proc_ns_operations timens_for_children_operations; + struct ns_common { struct dentry *stashed; const struct proc_ns_operations *ops;
@@ -84,10 +95,21 @@ void __ns_common_free(struct ns_common *ns); struct user_namespace *: &init_user_ns, \ struct uts_namespace *: &init_uts_ns) -#define ns_common_init(__ns, __ops) \ - __ns_common_init(to_ns_common(__ns), __ops, (((__ns) == ns_init_ns(__ns)) ? ns_init_inum(__ns) : 0)) - -#define ns_common_init_inum(__ns, __ops, __inum) __ns_common_init(to_ns_common(__ns), __ops, __inum) +#define to_ns_operations(__ns) \ + _Generic((__ns), \ + struct cgroup_namespace *: (IS_ENABLED(CONFIG_CGROUPS) ? &cgroupns_operations : NULL), \ + struct ipc_namespace *: (IS_ENABLED(CONFIG_IPC_NS) ? &ipcns_operations : NULL), \ + struct mnt_namespace *: &mntns_operations, \ + struct net *: (IS_ENABLED(CONFIG_NET_NS) ? &netns_operations : NULL), \ + struct pid_namespace *: (IS_ENABLED(CONFIG_PID_NS) ? &pidns_operations : NULL), \ + struct time_namespace *: (IS_ENABLED(CONFIG_TIME_NS) ? &timens_operations : NULL), \ + struct user_namespace *: (IS_ENABLED(CONFIG_USER_NS) ? &userns_operations : NULL), \ + struct uts_namespace *: (IS_ENABLED(CONFIG_UTS_NS) ? &utsns_operations : NULL)) + +#define ns_common_init(__ns) \ + __ns_common_init(to_ns_common(__ns), to_ns_operations(__ns), (((__ns) == ns_init_ns(__ns)) ? ns_init_inum(__ns) : 0)) + +#define ns_common_init_inum(__ns, __inum) __ns_common_init(to_ns_common(__ns), to_ns_operations(__ns), __inum) #define ns_common_free(__ns) __ns_common_free(to_ns_common((__ns)))
diff --git a/ipc/namespace.c b/ipc/namespace.c
index bd85d1c9d2c2..d89dfd718d2b 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c@@ -62,7 +62,7 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, if (ns == NULL) goto fail_dec; - err = ns_common_init(ns, &ipcns_operations); + err = ns_common_init(ns); if (err) goto fail_free;
diff --git a/kernel/cgroup/namespace.c b/kernel/cgroup/namespace.c
index 16ead7508371..04c98338ac08 100644
--- a/kernel/cgroup/namespace.c
+++ b/kernel/cgroup/namespace.c@@ -27,7 +27,7 @@ static struct cgroup_namespace *alloc_cgroup_ns(void) new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL_ACCOUNT); if (!new_ns) return ERR_PTR(-ENOMEM); - ret = ns_common_init(new_ns, &cgroupns_operations); + ret = ns_common_init(new_ns); if (ret) return ERR_PTR(ret); ns_tree_add(new_ns);
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 162f5fb63d75..a262a3f19443 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c@@ -103,7 +103,7 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns if (ns->pid_cachep == NULL) goto out_free_idr; - err = ns_common_init(ns, &pidns_operations); + err = ns_common_init(ns); if (err) goto out_free_idr;
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index 7aa4d6fedd49..9f26e61be044 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c@@ -97,7 +97,7 @@ static struct time_namespace *clone_time_ns(struct user_namespace *user_ns, if (!ns->vvar_page) goto fail_free; - err = ns_common_init(ns, &timens_operations); + err = ns_common_init(ns); if (err) goto fail_free_page;
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index f9df45c46235..e1559e8a8a02 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c@@ -126,7 +126,7 @@ int create_user_ns(struct cred *new) ns->parent_could_setfcap = cap_raised(new->cap_effective, CAP_SETFCAP); - ret = ns_common_init(ns, &userns_operations); + ret = ns_common_init(ns); if (ret) goto fail_free;
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 95d733eb2c98..00001592ad13 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c@@ -50,7 +50,7 @@ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, if (!ns) goto fail_dec; - err = ns_common_init(ns, &utsns_operations); + err = ns_common_init(ns); if (err) goto fail_free;
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index d5e3fd819163..bdea7d5fac56 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c@@ -400,16 +400,9 @@ static __net_init void preinit_net_sysctl(struct net *net) /* init code that must occur even if setup_net() is not called. */ static __net_init int preinit_net(struct net *net, struct user_namespace *user_ns) { - const struct proc_ns_operations *ns_ops; int ret; -#ifdef CONFIG_NET_NS - ns_ops = &netns_operations; -#else - ns_ops = NULL; -#endif - - ret = ns_common_init(net, ns_ops); + ret = ns_common_init(net); if (ret) return ret;
--
2.47.3