Unverified Commit bb57289f authored by Christian Brauner's avatar Christian Brauner
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Merge patch series "ns: rework common initialization" 

Christian Brauner <brauner@kernel.org> says:

The current scheme still involves a lot of open-coding and copy-pasing
and bleeds a lot of unnecessary details into actual namespace
implementers. Encapsulate it in the common helpers and simplify it all.

* patches from https://lore.kernel.org/20250917-work-namespace-ns_common-v1-0-1b3bda8ef8f2@kernel.org

:
  ns: add ns_common_free()
  nscommon: simplify initialization
  net: centralize ns_common initialization
  mnt: simplify ns_common_init() handling
  nsfs: add inode number for anon namespace
  cgroup: split namespace into separate header
  nscommon: move to separate file
  mnt: expose pointer to init_mnt_ns
  uts: split namespace into separate header

Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 3ab378cf be5f21d3

fs/namespace.c

+22 −14
Original line number Diff line number Diff line
@@ -4082,7 +4082,7 @@ static void dec_mnt_namespaces(struct ucounts *ucounts) 
static void free_mnt_ns(struct mnt_namespace *ns)

{

	if (!is_anon_ns(ns))

		ns_free_inum(&ns->ns);

		ns_common_free(ns);

	dec_mnt_namespaces(ns->ucounts);

	mnt_ns_tree_remove(ns);

}
@@ -4103,7 +4103,10 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool a 
		return ERR_PTR(-ENOMEM);

	}



	ret = ns_common_init(&new_ns->ns, &mntns_operations, !anon);

	if (anon)

		ret = ns_common_init_inum(new_ns, &mntns_operations, MNT_NS_ANON_INO);

	else

		ret = ns_common_init(new_ns, &mntns_operations);

	if (ret) {

		kfree(new_ns);

		dec_mnt_namespaces(ucounts);
@@ -4151,7 +4154,7 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns, 
	new = copy_tree(old, old->mnt.mnt_root, copy_flags);

	if (IS_ERR(new)) {

		namespace_unlock();

		ns_free_inum(&new_ns->ns);

		ns_common_free(ns);

		dec_mnt_namespaces(new_ns->ucounts);

		mnt_ns_release(new_ns);

		return ERR_CAST(new);
@@ -6008,27 +6011,32 @@ SYSCALL_DEFINE4(listmount, const struct mnt_id_req __user *, req, 
	return ret;

}



struct mnt_namespace init_mnt_ns = {

	.ns.inum	= PROC_MNT_INIT_INO,

	.ns.ops		= &mntns_operations,

	.user_ns	= &init_user_ns,

	.ns.count	= REFCOUNT_INIT(1),

	.passive	= REFCOUNT_INIT(1),

	.mounts		= RB_ROOT,

	.poll		= __WAIT_QUEUE_HEAD_INITIALIZER(init_mnt_ns.poll),

};



static void __init init_mount_tree(void)

{

	struct vfsmount *mnt;

	struct mount *m;

	struct mnt_namespace *ns;

	struct path root;



	mnt = vfs_kern_mount(&rootfs_fs_type, 0, "rootfs", NULL);

	if (IS_ERR(mnt))

		panic("Can't create rootfs");



	ns = alloc_mnt_ns(&init_user_ns, true);

	if (IS_ERR(ns))

		panic("Can't allocate initial namespace");

	ns->ns.inum = PROC_MNT_INIT_INO;

	m = real_mount(mnt);

	ns->root = m;

	ns->nr_mounts = 1;

	mnt_add_to_ns(ns, m);

	init_task.nsproxy->mnt_ns = ns;

	get_mnt_ns(ns);

	init_mnt_ns.root = m;

	init_mnt_ns.nr_mounts = 1;

	mnt_add_to_ns(&init_mnt_ns, m);

	init_task.nsproxy->mnt_ns = &init_mnt_ns;

	get_mnt_ns(&init_mnt_ns);



	root.mnt = mnt;

	root.dentry = mnt->mnt_root;
@@ -6036,7 +6044,7 @@ static void __init init_mount_tree(void) 
	set_fs_pwd(current->fs, &root);

	set_fs_root(current->fs, &root);



	ns_tree_add(ns);

	ns_tree_add(&init_mnt_ns);

}



void __init mnt_init(void)

include/linux/cgroup.h

+1 −50
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/kernel_stat.h>



#include <linux/cgroup-defs.h>

#include <linux/cgroup_namespace.h>



struct kernel_clone_args;
@@ -783,56 +784,6 @@ static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} 


#endif	/* CONFIG_CGROUP_DATA */



struct cgroup_namespace {

	struct ns_common	ns;

	struct user_namespace	*user_ns;

	struct ucounts		*ucounts;

	struct css_set          *root_cset;

};



extern struct cgroup_namespace init_cgroup_ns;



#ifdef CONFIG_CGROUPS



static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)

{

	return container_of(ns, struct cgroup_namespace, ns);

}



void free_cgroup_ns(struct cgroup_namespace *ns);



struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,

					struct user_namespace *user_ns,

					struct cgroup_namespace *old_ns);



int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,

		   struct cgroup_namespace *ns);



static inline void get_cgroup_ns(struct cgroup_namespace *ns)

{

	refcount_inc(&ns->ns.count);

}



static inline void put_cgroup_ns(struct cgroup_namespace *ns)

{

	if (refcount_dec_and_test(&ns->ns.count))

		free_cgroup_ns(ns);

}



#else /* !CONFIG_CGROUPS */



static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }

static inline struct cgroup_namespace *

copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,

	       struct cgroup_namespace *old_ns)

{

	return old_ns;

}



static inline void get_cgroup_ns(struct cgroup_namespace *ns) { }

static inline void put_cgroup_ns(struct cgroup_namespace *ns) { }



#endif /* !CONFIG_CGROUPS */



#ifdef CONFIG_CGROUPS

include/linux/cgroup_namespace.h

0 → 100644
+56 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _LINUX_CGROUP_NAMESPACE_H

#define _LINUX_CGROUP_NAMESPACE_H



struct cgroup_namespace {

	struct ns_common	ns;

	struct user_namespace	*user_ns;

	struct ucounts		*ucounts;

	struct css_set          *root_cset;

};



extern struct cgroup_namespace init_cgroup_ns;



#ifdef CONFIG_CGROUPS



static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)

{

	return container_of(ns, struct cgroup_namespace, ns);

}



void free_cgroup_ns(struct cgroup_namespace *ns);



struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,

					struct user_namespace *user_ns,

					struct cgroup_namespace *old_ns);



int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,

		   struct cgroup_namespace *ns);



static inline void get_cgroup_ns(struct cgroup_namespace *ns)

{

	refcount_inc(&ns->ns.count);

}



static inline void put_cgroup_ns(struct cgroup_namespace *ns)

{

	if (refcount_dec_and_test(&ns->ns.count))

		free_cgroup_ns(ns);

}



#else /* !CONFIG_CGROUPS */



static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }

static inline struct cgroup_namespace *

copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,

	       struct cgroup_namespace *old_ns)

{

	return old_ns;

}



static inline void get_cgroup_ns(struct cgroup_namespace *ns) { }

static inline void put_cgroup_ns(struct cgroup_namespace *ns) { }



#endif /* !CONFIG_CGROUPS */



#endif /* _LINUX_CGROUP_NAMESPACE_H */

include/linux/mnt_namespace.h

+2 −0
Original line number Diff line number Diff line
@@ -11,6 +11,8 @@ struct fs_struct; 
struct user_namespace;

struct ns_common;



extern struct mnt_namespace init_mnt_ns;



extern struct mnt_namespace *copy_mnt_ns(unsigned long, struct mnt_namespace *,

		struct user_namespace *, struct fs_struct *);

extern void put_mnt_ns(struct mnt_namespace *ns);

include/linux/ns_common.h

+41 −0
Original line number Diff line number Diff line
@@ -16,6 +16,15 @@ struct time_namespace; 
struct user_namespace;

struct uts_namespace;



extern struct cgroup_namespace init_cgroup_ns;

extern struct ipc_namespace init_ipc_ns;

extern struct mnt_namespace init_mnt_ns;

extern struct net init_net;

extern struct pid_namespace init_pid_ns;

extern struct time_namespace init_time_ns;

extern struct user_namespace init_user_ns;

extern struct uts_namespace init_uts_ns;



struct ns_common {

	struct dentry *stashed;

	const struct proc_ns_operations *ops;
@@ -31,6 +40,9 @@ struct ns_common { 
	};

};



int __ns_common_init(struct ns_common *ns, const struct proc_ns_operations *ops, int inum);

void __ns_common_free(struct ns_common *ns);



#define to_ns_common(__ns)                              \

	_Generic((__ns),                                \

		struct cgroup_namespace *: &(__ns)->ns, \
@@ -42,4 +54,33 @@ struct ns_common { 
		struct user_namespace *:   &(__ns)->ns, \

		struct uts_namespace *:    &(__ns)->ns)



#define ns_init_inum(__ns)                                     \

	_Generic((__ns),                                       \

		struct cgroup_namespace *: CGROUP_NS_INIT_INO, \

		struct ipc_namespace *:    IPC_NS_INIT_INO,    \

		struct mnt_namespace *:    MNT_NS_INIT_INO,    \

		struct net *:              NET_NS_INIT_INO,    \

		struct pid_namespace *:    PID_NS_INIT_INO,    \

		struct time_namespace *:   TIME_NS_INIT_INO,   \

		struct user_namespace *:   USER_NS_INIT_INO,   \

		struct uts_namespace *:    UTS_NS_INIT_INO)



#define ns_init_ns(__ns)                                    \

	_Generic((__ns),                                    \

		struct cgroup_namespace *: &init_cgroup_ns, \

		struct ipc_namespace *:    &init_ipc_ns,    \

		struct mnt_namespace *:    &init_mnt_ns,     \

		struct net *:              &init_net,       \

		struct pid_namespace *:    &init_pid_ns,    \

		struct time_namespace *:   &init_time_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 ns_common_free(__ns) __ns_common_free(to_ns_common((__ns)))



#endif