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 84