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Move a locking function that was spread throughout disk device drivers into
the disk structure.

The locking was mostly used in disk device drivers to prevent multiple
disklabel operations from going on simultaneously against the device.

Added disk_construct(), a constructor for the disk structure, that
initializes the lock structure in disk. It is called by default in
disk_attach() if it hasn't been called yet.

Added disk_lock and disk_unlock

/*	$OpenBSD: disk.h,v 1.5 2000/04/09 19:26:35 csapuntz Exp $	*/
/*	$NetBSD: disk.h,v 1.11 1996/04/28 20:22:50 thorpej Exp $	*/

/*
 * Copyright (c) 1995 Jason R. Thorpe.  All rights reserved.
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * All advertising materials mentioning features or use of this software
 * must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Lawrence Berkeley Laboratory.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * from: Header: disk.h,v 1.5 92/11/19 04:33:03 torek Exp  (LBL)
 *
 *	@(#)disk.h	8.1 (Berkeley) 6/2/93
 */

/*
 * Disk device structures.
 */

#include <sys/time.h>
#include <sys/queue.h>
#include <sys/lock.h>

struct buf;
struct disklabel;
struct cpu_disklabel;

struct disk {
	TAILQ_ENTRY(disk) dk_link;	/* link in global disklist */
	struct lock     dk_lock;        /* disk lock */
	char		*dk_name;	/* disk name */
	int             dk_flags;       /* disk flags */
#define DKF_CONSTRUCTED  0x0001
	int		dk_bopenmask;	/* block devices open */
	int		dk_copenmask;	/* character devices open */
	int		dk_openmask;	/* composite (bopen|copen) */
	int		dk_state;	/* label state   ### */
	int		dk_blkshift;	/* shift to convert DEV_BSIZE to blks */
	int		dk_byteshift;	/* shift to convert bytes to blks */

	/*
	 * Metrics data; note that some metrics may have no meaning
	 * on certain types of disks.
	 */
	int		dk_busy;	/* busy counter */
	u_int64_t	dk_xfer;	/* total number of transfers */
	u_int64_t	dk_seek;	/* total independent seek operations */
	u_int64_t	dk_bytes;	/* total bytes transfered */
	struct timeval	dk_attachtime;	/* time disk was attached */
	struct timeval	dk_timestamp;	/* timestamp of last unbusy */
	struct timeval	dk_time;	/* total time spent busy */

	struct	dkdriver *dk_driver;	/* pointer to driver */

	/*
	 * Disk label information.  Storage for the in-core disk label
	 * must be dynamically allocated, otherwise the size of this
	 * structure becomes machine-dependent.
	 */
	daddr_t		dk_labelsector;		/* sector containing label */
	struct disklabel *dk_label;	/* label */
	struct cpu_disklabel *dk_cpulabel;
};

struct dkdriver {
	void	(*d_strategy) __P((struct buf *));
#ifdef notyet
	int	(*d_open) __P((dev_t dev, int ifmt, int, struct proc *));
	int	(*d_close) __P((dev_t dev, int, int ifmt, struct proc *));
	int	(*d_ioctl) __P((dev_t dev, u_long cmd, caddr_t data, int fflag,
				struct proc *));
	int	(*d_dump) __P((dev_t));
	void	(*d_start) __P((struct buf *, daddr_t));
	int	(*d_mklabel) __P((struct disk *));
#endif
};

/* states */
#define	DK_CLOSED	0		/* drive is closed */
#define	DK_WANTOPEN	1		/* drive being opened */
#define	DK_WANTOPENRAW	2		/* drive being opened */
#define	DK_RDLABEL	3		/* label being read */
#define	DK_OPEN		4		/* label read, drive open */
#define	DK_OPENRAW	5		/* open without label */

#ifdef DISKSORT_STATS
/*
 * Stats from disksort().
 */
struct disksort_stats {
	long	ds_newhead;		/* # new queue heads created */
	long	ds_newtail;		/* # new queue tails created */
	long	ds_midfirst;		/* # insertions into sort list */
	long	ds_endfirst;		/* # insertions at end of sort list */
	long	ds_newsecond;		/* # inversions (2nd lists) created */
	long	ds_midsecond;		/* # insertions into 2nd list */
	long	ds_endsecond;		/* # insertions at end of 2nd list */
};
#endif

/*
 * disklist_head is defined here so that user-land has access to it.
 */
TAILQ_HEAD(disklist_head, disk);	/* the disklist is a TAILQ */

#ifdef _KERNEL
extern	int disk_count;			/* number of disks in global disklist */

void	disk_init __P((void));
int     disk_construct __P((struct disk *, char *));
void	disk_attach __P((struct disk *));
void	disk_detach __P((struct disk *));
void	disk_busy __P((struct disk *));
void	disk_unbusy __P((struct disk *, long));
void	disk_resetstat __P((struct disk *));
struct	disk *disk_find __P((char *));

int     disk_lock __P((struct disk *));
void    disk_unlock __P((struct disk *));

struct device;
void	dk_establish __P((struct disk *, struct device *));
#endif