4.3BSD-Reno/src/sys/sys/specdev.h

/*
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution is only permitted until one year after the first shipment
 * of 4.4BSD by the Regents.  Otherwise, redistribution and use in source and
 * binary forms are permitted provided that: (1) source distributions retain
 * this entire copyright notice and comment, and (2) distributions including
 * binaries display the following acknowledgement:  This product includes
 * software developed by the University of California, Berkeley and its
 * contributors'' in the documentation or other materials provided with the
 * distribution and in all advertising materials mentioning features or use
 * of this software.  Neither the name of the University nor the names of
 * its contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *	@(#)specdev.h	7.2 (Berkeley) 6/28/90
 */

/*
 * This structure defines the information maintained about
 * special devices. It is allocated in checkalias and freed
 * in vgone.
 */
struct specinfo {
	struct	vnode **si_hashchain;
	struct	vnode *si_specnext;
	long	si_flags;
	dev_t	si_rdev;
};
/*
 * Exported shorthand
 */
#define v_rdev v_specinfo->si_rdev
#define v_hashchain v_specinfo->si_hashchain
#define v_specnext v_specinfo->si_specnext
#define v_specflags v_specinfo->si_flags

/*
 * Flags for specinfo
 */
#define	SI_MOUNTEDON	0x0001	/* block special device is mounted on */

/*
 * Special device management
 */
#define	SPECHSZ	64
#if	((SPECHSZ&(SPECHSZ-1)) == 0)
#define	SPECHASH(rdev)	(((rdev>>5)+(rdev))&(SPECHSZ-1))
#else
#define	SPECHASH(rdev)	(((unsigned)((rdev>>5)+(rdev)))%SPECHSZ)
#endif

struct vnode *speclisth[SPECHSZ];