Messages in this thread | | | From | Andries.Brouwer@cwi ... | Date | Thu, 27 Mar 2003 02:09:22 +0100 (MET) | Subject | 64-bit kdev_t - just for playing |
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>> Maybe I should send another patch tonight, just for playing.
> Please, I'd like that.
Below a random version of kdev_t.h. (The file is smaller than the patch.)
kdev_t is the kernel-internal representation dev_t is the kernel idea of the user space representation (of course glibc uses 64 bits, split up as 8+8 :-)
kdev_t can be equal to dev_t.
The file below completely randomly makes kdev_t 64 bits, split up 32+32, and dev_t 32 bits, split up 12+20.
Andries
------------------------------------------------------------ #ifndef _LINUX_KDEV_T_H #define _LINUX_KDEV_T_H #ifdef __KERNEL__
typedef struct { unsigned long long value; } kdev_t;
#define KDEV_MINOR_BITS 32 #define KDEV_MAJOR_BITS 32 #define KDEV_MINOR_MASK ((1ULL << KDEV_MINOR_BITS) - 1)
#define __mkdev(major, minor) (((unsigned long long)(major) << KDEV_MINOR_BITS) + (minor))
#define mk_kdev(major, minor) ((kdev_t) { __mkdev(major,minor) } )
/* * The "values" are just _cookies_, usable for * internal equality comparisons and for things * like NFS filehandle conversion. */ static inline unsigned long long kdev_val(kdev_t dev) { return dev.value; }
static inline kdev_t val_to_kdev(unsigned long long val) { kdev_t dev; dev.value = val; return dev; }
#define HASHDEV(dev) (kdev_val(dev)) #define NODEV (mk_kdev(0,0))
extern const char * kdevname(kdev_t); /* note: returns pointer to static data! */
static inline int kdev_same(kdev_t dev1, kdev_t dev2) { return dev1.value == dev2.value; }
#define kdev_none(d1) (!kdev_val(d1))
#define minor(dev) (unsigned int)((dev).value & KDEV_MINOR_MASK) #define major(dev) (unsigned int)((dev).value >> KDEV_MINOR_BITS)
/* These are for user-level "dev_t" */ #define MINORBITS 8 #define MINORMASK ((1U << MINORBITS) - 1) #define DEV_MINOR_BITS 20 #define DEV_MAJOR_BITS 12 #define DEV_MINOR_MASK ((1U << DEV_MINOR_BITS) - 1) #define DEV_MAJOR_MASK ((1U << DEV_MAJOR_BITS) - 1)
#include <linux/types.h> /* dev_t */
#define MAJOR(dev) ((unsigned int)(((dev) & 0xffff0000) ? ((dev) >> DEV_MINOR_BITS) & DEV_MAJOR_MASK : ((dev) >> 8) & 0xff)) #define MINOR(dev) ((unsigned int)(((dev) & 0xffff0000) ? ((dev) & DEV_MINOR_MASK) : ((dev) & 0xff))) #define MKDEV(ma,mi) ((dev_t)((((ma) & ~0xff) == 0 && ((mi) & ~0xff) == 0) ? (((ma) << 8) | (mi)) : (((ma) << DEV_MINOR_BITS) | (mi))))
/* * Conversion functions */
static inline int kdev_t_to_nr(kdev_t dev) { unsigned int ma = major(dev); unsigned int mi = minor(dev); return MKDEV(ma, mi); }
static inline kdev_t to_kdev_t(dev_t dev) { unsigned int ma = MAJOR(dev); unsigned int mi = MINOR(dev); return mk_kdev(ma, mi); }
#else /* __KERNEL__ */
/* Some programs want their definitions of MAJOR and MINOR and MKDEV from the kernel sources. These must be the externally visible ones. Of course such programs should be updated. */ #define MAJOR(dev) ((dev)>>8) #define MINOR(dev) ((dev) & 0xff) #define MKDEV(ma,mi) ((ma)<<8 | (mi)) #endif /* __KERNEL__ */ #endif - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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