Home | History | Annotate | Download | only in linux 
      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 */
     21 static inline int old_valid_dev(dev_t dev)
     22 {
     23 	return MAJOR(dev) < 256 && MINOR(dev) < 256;
     24 }
     25 
     26 static inline u16 old_encode_dev(dev_t dev)
     27 {
     28 	return (MAJOR(dev) << 8) | MINOR(dev);
     29 }
     30 
     31 static inline dev_t old_decode_dev(u16 val)
     32 {
     33 	return MKDEV((val >> 8) & 255, val & 255);
     34 }
     35 
     36 static inline int new_valid_dev(dev_t dev)
     37 {
     38 	return 1;
     39 }
     40 
     41 static 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 
     48 static 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 
     55 static inline int huge_valid_dev(dev_t dev)
     56 {
     57 	return 1;
     58 }
     59 
     60 static inline u64 huge_encode_dev(dev_t dev)
     61 {
     62 	return new_encode_dev(dev);
     63 }
     64 
     65 static inline dev_t huge_decode_dev(u64 dev)
     66 {
     67 	return new_decode_dev(dev);
     68 }
     69 
     70 static inline int sysv_valid_dev(dev_t dev)
     71 {
     72 	return MAJOR(dev) < (1<<14) && MINOR(dev) < (1<<18);
     73 }
     74 
     75 static inline u32 sysv_encode_dev(dev_t dev)
     76 {
     77 	return MINOR(dev) | (MAJOR(dev) << 18);
     78 }
     79 
     80 static inline unsigned sysv_major(u32 dev)
     81 {
     82 	return (dev >> 18) & 0x3fff;
     83 }
     84 
     85 static inline unsigned sysv_minor(u32 dev)
     86 {
     87 	return dev & 0x3ffff;
     88 }
     89 
     90 
     91 #else /* __KERNEL__ */
     92 
     93 /*
     94 Some programs want their definitions of MAJOR and MINOR and MKDEV
     95 from the kernel sources. These must be the externally visible ones.
     96 */
     97 #define MAJOR(dev)	((dev)>>8)
     98 #define MINOR(dev)	((dev) & 0xff)
     99 #define MKDEV(ma,mi)	((ma)<<8 | (mi))
    100 #endif /* __KERNEL__ */
    101 #endif
    102