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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_NS_COMMON_H
3#define _LINUX_NS_COMMON_H
4
5#include <linux/ns/ns_common_types.h>
6#include <linux/refcount.h>
7#include <linux/vfsdebug.h>
8#include <uapi/linux/sched.h>
9#include <uapi/linux/nsfs.h>
10
11bool is_current_namespace(struct ns_common *ns);
12int __ns_common_init(struct ns_common *ns, u32 ns_type, const struct proc_ns_operations *ops, int inum);
13void __ns_common_free(struct ns_common *ns);
14struct ns_common *__must_check ns_owner(struct ns_common *ns);
15
16static __always_inline bool is_ns_init_inum(const struct ns_common *ns)
17{
18 VFS_WARN_ON_ONCE(ns->inum == 0);
19 return unlikely(in_range(ns->inum, MNT_NS_INIT_INO,
20 IPC_NS_INIT_INO - MNT_NS_INIT_INO + 1));
21}
22
23static __always_inline bool is_ns_init_id(const struct ns_common *ns)
24{
25 VFS_WARN_ON_ONCE(ns->ns_id == 0);
26 return ns->ns_id <= NS_LAST_INIT_ID;
27}
28
29#define NS_COMMON_INIT(nsname) \
30{ \
31 .ns_type = ns_common_type(&nsname), \
32 .ns_id = ns_init_id(&nsname), \
33 .inum = ns_init_inum(&nsname), \
34 .ops = to_ns_operations(&nsname), \
35 .stashed = NULL, \
36 .__ns_ref = REFCOUNT_INIT(1), \
37 .__ns_ref_active = ATOMIC_INIT(1), \
38 .ns_unified_node.ns_list_entry = LIST_HEAD_INIT(nsname.ns.ns_unified_node.ns_list_entry), \
39 .ns_tree_node.ns_list_entry = LIST_HEAD_INIT(nsname.ns.ns_tree_node.ns_list_entry), \
40 .ns_owner_node.ns_list_entry = LIST_HEAD_INIT(nsname.ns.ns_owner_node.ns_list_entry), \
41 .ns_owner_root.ns_list_head = LIST_HEAD_INIT(nsname.ns.ns_owner_root.ns_list_head), \
42}
43
44#define ns_common_init(__ns) \
45 __ns_common_init(to_ns_common(__ns), \
46 ns_common_type(__ns), \
47 to_ns_operations(__ns), \
48 (((__ns) == ns_init_ns(__ns)) ? ns_init_inum(__ns) : 0))
49
50#define ns_common_init_inum(__ns, __inum) \
51 __ns_common_init(to_ns_common(__ns), \
52 ns_common_type(__ns), \
53 to_ns_operations(__ns), \
54 __inum)
55
56#define ns_common_free(__ns) __ns_common_free(to_ns_common((__ns)))
57
58static __always_inline __must_check int __ns_ref_active_read(const struct ns_common *ns)
59{
60 return atomic_read(v: &ns->__ns_ref_active);
61}
62
63static __always_inline __must_check int __ns_ref_read(const struct ns_common *ns)
64{
65 return refcount_read(r: &ns->__ns_ref);
66}
67
68static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns)
69{
70 if (is_ns_init_id(ns)) {
71 VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
72 VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
73 return false;
74 }
75 if (refcount_dec_and_test(r: &ns->__ns_ref)) {
76 VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));
77 return true;
78 }
79 return false;
80}
81
82static __always_inline __must_check bool __ns_ref_get(struct ns_common *ns)
83{
84 if (is_ns_init_id(ns)) {
85 VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
86 VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
87 return true;
88 }
89 if (refcount_inc_not_zero(r: &ns->__ns_ref))
90 return true;
91 VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));
92 return false;
93}
94
95static __always_inline void __ns_ref_inc(struct ns_common *ns)
96{
97 if (is_ns_init_id(ns)) {
98 VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
99 VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
100 return;
101 }
102 refcount_inc(r: &ns->__ns_ref);
103}
104
105static __always_inline __must_check bool __ns_ref_dec_and_lock(struct ns_common *ns,
106 spinlock_t *ns_lock)
107{
108 if (is_ns_init_id(ns)) {
109 VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
110 VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
111 return false;
112 }
113 return refcount_dec_and_lock(r: &ns->__ns_ref, lock: ns_lock);
114}
115
116#define ns_ref_read(__ns) __ns_ref_read(to_ns_common((__ns)))
117#define ns_ref_inc(__ns) \
118 do { if (__ns) __ns_ref_inc(to_ns_common((__ns))); } while (0)
119#define ns_ref_get(__ns) \
120 ((__ns) ? __ns_ref_get(to_ns_common((__ns))) : false)
121#define ns_ref_put(__ns) \
122 ((__ns) ? __ns_ref_put(to_ns_common((__ns))) : false)
123#define ns_ref_put_and_lock(__ns, __ns_lock) \
124 ((__ns) ? __ns_ref_dec_and_lock(to_ns_common((__ns)), __ns_lock) : false)
125
126#define ns_ref_active_read(__ns) \
127 ((__ns) ? __ns_ref_active_read(to_ns_common(__ns)) : 0)
128
129void __ns_ref_active_put(struct ns_common *ns);
130
131#define ns_ref_active_put(__ns) \
132 do { if (__ns) __ns_ref_active_put(to_ns_common(__ns)); } while (0)
133
134static __always_inline struct ns_common *__must_check ns_get_unless_inactive(struct ns_common *ns)
135{
136 if (!__ns_ref_active_read(ns)) {
137 VFS_WARN_ON_ONCE(is_ns_init_id(ns));
138 return NULL;
139 }
140 if (!__ns_ref_get(ns))
141 return NULL;
142 return ns;
143}
144
145void __ns_ref_active_get(struct ns_common *ns);
146
147#define ns_ref_active_get(__ns) \
148 do { if (__ns) __ns_ref_active_get(to_ns_common(__ns)); } while (0)
149
150#endif
151

source code of linux/include/linux/ns_common.h