Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 bool 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 u32 new_encode_dev(dev_t dev)
39{
40 unsigned major = MAJOR(dev);
41 unsigned minor = MINOR(dev);
42 return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
43}
44
45static inline dev_t new_decode_dev(u32 dev)
46{
47 unsigned major = (dev & 0xfff00) >> 8;
48 unsigned minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
49 return MKDEV(major, minor);
50}
51
52static inline u64 huge_encode_dev(dev_t dev)
53{
54 return new_encode_dev(dev);
55}
56
57static inline dev_t huge_decode_dev(u64 dev)
58{
59 return new_decode_dev(dev);
60}
61
62static inline int sysv_valid_dev(dev_t dev)
63{
64 return MAJOR(dev) < (1<<14) && MINOR(dev) < (1<<18);
65}
66
67static inline u32 sysv_encode_dev(dev_t dev)
68{
69 return MINOR(dev) | (MAJOR(dev) << 18);
70}
71
72static inline unsigned sysv_major(u32 dev)
73{
74 return (dev >> 18) & 0x3fff;
75}
76
77static inline unsigned sysv_minor(u32 dev)
78{
79 return dev & 0x3ffff;
80}
81
82#endif