1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_KDEV_T_H
3#define _LINUX_KDEV_T_H
4
5#include <uapi/linux/kdev_t.h>
6
7#define MINORBITS	20
8#define MINORMASK	((1U << MINORBITS) - 1)
9
10#define MAJOR(dev)	((unsigned int) ((dev) >> MINORBITS))
11#define MINOR(dev)	((unsigned int) ((dev) & MINORMASK))
12#define MKDEV(ma,mi)	(((ma) << MINORBITS) | (mi))
13
14#define print_dev_t(buffer, dev)					\
15	sprintf((buffer), "%u:%u\n", MAJOR(dev), MINOR(dev))
16
17#define format_dev_t(buffer, dev)					\
18	({								\
19		sprintf(buffer, "%u:%u", MAJOR(dev), MINOR(dev));	\
20		buffer;							\
21	})
22
23/* acceptable for old filesystems */
24static __always_inline bool old_valid_dev(dev_t dev)
25{
26	return MAJOR(dev) < 256 && MINOR(dev) < 256;
27}
28
29static __always_inline u16 old_encode_dev(dev_t dev)
30{
31	return (MAJOR(dev) << 8) | MINOR(dev);
32}
33
34static __always_inline dev_t old_decode_dev(u16 val)
35{
36	return MKDEV((val >> 8) & 255, val & 255);
37}
38
39static __always_inline u32 new_encode_dev(dev_t dev)
40{
41	unsigned major = MAJOR(dev);
42	unsigned minor = MINOR(dev);
43	return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
44}
45
46static __always_inline dev_t new_decode_dev(u32 dev)
47{
48	unsigned major = (dev & 0xfff00) >> 8;
49	unsigned minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
50	return MKDEV(major, minor);
51}
52
53static __always_inline u64 huge_encode_dev(dev_t dev)
54{
55	return new_encode_dev(dev);
56}
57
58static __always_inline dev_t huge_decode_dev(u64 dev)
59{
60	return new_decode_dev(dev);
61}
62
63static __always_inline int sysv_valid_dev(dev_t dev)
64{
65	return MAJOR(dev) < (1<<14) && MINOR(dev) < (1<<18);
66}
67
68static __always_inline u32 sysv_encode_dev(dev_t dev)
69{
70	return MINOR(dev) | (MAJOR(dev) << 18);
71}
72
73static __always_inline unsigned sysv_major(u32 dev)
74{
75	return (dev >> 18) & 0x3fff;
76}
77
78static __always_inline unsigned sysv_minor(u32 dev)
79{
80	return dev & 0x3ffff;
81}
82
83#endif
84