1#ifndef _LINUX_KDEV_T_H
2#define _LINUX_KDEV_T_H
3#ifdef __KERNEL__
4#define MINORBITS	20
5#define MINORMASK	((1U << MINORBITS) - 1)
6
7#define MAJOR(dev)	((unsigned int) ((dev) >> MINORBITS))
8#define MINOR(dev)	((unsigned int) ((dev) & MINORMASK))
9#define MKDEV(ma,mi)	(((ma) << MINORBITS) | (mi))
10
11#define print_dev_t(buffer, dev)					\
12	sprintf((buffer), "%u:%u\n", MAJOR(dev), MINOR(dev))
13
14#define format_dev_t(buffer, dev)					\
15	({								\
16		sprintf(buffer, "%u:%u", MAJOR(dev), MINOR(dev));	\
17		buffer;							\
18	})
19
20/* acceptable for old filesystems */
21static inline int old_valid_dev(dev_t dev)
22{
23	return MAJOR(dev) < 256 && MINOR(dev) < 256;
24}
25
26static inline u16 old_encode_dev(dev_t dev)
27{
28	return (MAJOR(dev) << 8) | MINOR(dev);
29}
30
31static inline dev_t old_decode_dev(u16 val)
32{
33	return MKDEV((val >> 8) & 255, val & 255);
34}
35
36static inline int new_valid_dev(dev_t dev)
37{
38	return 1;
39}
40
41static inline u32 new_encode_dev(dev_t dev)
42{
43	unsigned major = MAJOR(dev);
44	unsigned minor = MINOR(dev);
45	return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
46}
47
48static inline dev_t new_decode_dev(u32 dev)
49{
50	unsigned major = (dev & 0xfff00) >> 8;
51	unsigned minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
52	return MKDEV(major, minor);
53}
54
55static inline int huge_valid_dev(dev_t dev)
56{
57	return 1;
58}
59
60static inline u64 huge_encode_dev(dev_t dev)
61{
62	return new_encode_dev(dev);
63}
64
65static inline dev_t huge_decode_dev(u64 dev)
66{
67	return new_decode_dev(dev);
68}
69
70static inline int sysv_valid_dev(dev_t dev)
71{
72	return MAJOR(dev) < (1<<14) && MINOR(dev) < (1<<18);
73}
74
75static inline u32 sysv_encode_dev(dev_t dev)
76{
77	return MINOR(dev) | (MAJOR(dev) << 18);
78}
79
80static inline unsigned sysv_major(u32 dev)
81{
82	return (dev >> 18) & 0x3fff;
83}
84
85static inline unsigned sysv_minor(u32 dev)
86{
87	return dev & 0x3ffff;
88}
89
90#else /* __KERNEL__ */
91
92/*
93Some programs want their definitions of MAJOR and MINOR and MKDEV
94from the kernel sources. These must be the externally visible ones.
95*/
96#define MAJOR(dev)	((dev)>>8)
97#define MINOR(dev)	((dev) & 0xff)
98#define MKDEV(ma,mi)	((ma)<<8 | (mi))
99#endif /* __KERNEL__ */
100#endif
101