kdev_t.h 1.8 KB

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