1#ifndef _LINUX_KDEV_T_H
2#define _LINUX_KDEV_T_H
3
4#include <uapi/linux/kdev_t.h>
5
6#define MINORBITS	20
7#define MINORMASK	((1U << MINORBITS) - 1)
8
9#define MAJOR(dev)	((unsigned int) ((dev) >> MINORBITS))
10#define MINOR(dev)	((unsigned int) ((dev) & MINORMASK))
11#define MKDEV(ma,mi)	(((ma) << MINORBITS) | (mi))
12
13#define print_dev_t(buffer, dev)					\
14	sprintf((buffer), "%u:%u\n", MAJOR(dev), MINOR(dev))
15
16#define format_dev_t(buffer, dev)					\
17	({								\
18		sprintf(buffer, "%u:%u", MAJOR(dev), MINOR(dev));	\
19		buffer;							\
20	})
21
22/* acceptable for old filesystems */
23static inline int old_valid_dev(dev_t dev)
24{
25	return MAJOR(dev) < 256 && MINOR(dev) < 256;
26}
27
28static inline u16 old_encode_dev(dev_t dev)
29{
30	return (MAJOR(dev) << 8) | MINOR(dev);
31}
32
33static inline dev_t old_decode_dev(u16 val)
34{
35	return MKDEV((val >> 8) & 255, val & 255);
36}
37
38static inline int new_valid_dev(dev_t dev)
39{
40	return 1;
41}
42
43static inline u32 new_encode_dev(dev_t dev)
44{
45	unsigned major = MAJOR(dev);
46	unsigned minor = MINOR(dev);
47	return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
48}
49
50static inline dev_t new_decode_dev(u32 dev)
51{
52	unsigned major = (dev & 0xfff00) >> 8;
53	unsigned minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
54	return MKDEV(major, minor);
55}
56
57static inline int huge_valid_dev(dev_t dev)
58{
59	return 1;
60}
61
62static inline u64 huge_encode_dev(dev_t dev)
63{
64	return new_encode_dev(dev);
65}
66
67static inline dev_t huge_decode_dev(u64 dev)
68{
69	return new_decode_dev(dev);
70}
71
72static inline int sysv_valid_dev(dev_t dev)
73{
74	return MAJOR(dev) < (1<<14) && MINOR(dev) < (1<<18);
75}
76
77static inline u32 sysv_encode_dev(dev_t dev)
78{
79	return MINOR(dev) | (MAJOR(dev) << 18);
80}
81
82static inline unsigned sysv_major(u32 dev)
83{
84	return (dev >> 18) & 0x3fff;
85}
86
87static inline unsigned sysv_minor(u32 dev)
88{
89	return dev & 0x3ffff;
90}
91
92#endif
93