root/include/linux/kdev_t.h

INCLUDED FROM

DEFINITIONS

1. old_valid_dev
2. old_encode_dev
3. old_decode_dev
4. new_encode_dev
5. new_decode_dev
6. huge_encode_dev
7. huge_decode_dev
8. sysv_valid_dev
9. sysv_encode_dev
10. sysv_major
11. sysv_minor

   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 */
  24 static inline bool old_valid_dev(dev_t dev)
  25 {
  26         return MAJOR(dev) < 256 && MINOR(dev) < 256;
  27 }
  28 
  29 static inline u16 old_encode_dev(dev_t dev)
  30 {
  31         return (MAJOR(dev) << 8) | MINOR(dev);
  32 }
  33 
  34 static inline dev_t old_decode_dev(u16 val)
  35 {
  36         return MKDEV((val >> 8) & 255, val & 255);
  37 }
  38 
  39 static 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 
  46 static 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 
  53 static inline u64 huge_encode_dev(dev_t dev)
  54 {
  55         return new_encode_dev(dev);
  56 }
  57 
  58 static inline dev_t huge_decode_dev(u64 dev)
  59 {
  60         return new_decode_dev(dev);
  61 }
  62 
  63 static inline int sysv_valid_dev(dev_t dev)
  64 {
  65         return MAJOR(dev) < (1<<14) && MINOR(dev) < (1<<18);
  66 }
  67 
  68 static inline u32 sysv_encode_dev(dev_t dev)
  69 {
  70         return MINOR(dev) | (MAJOR(dev) << 18);
  71 }
  72 
  73 static inline unsigned sysv_major(u32 dev)
  74 {
  75         return (dev >> 18) & 0x3fff;
  76 }
  77 
  78 static inline unsigned sysv_minor(u32 dev)
  79 {
  80         return dev & 0x3ffff;
  81 }
  82 
  83 #endif