/*	$OpenBSD: rf_stripelocks.h,v 1.3 2002/12/16 07:01:05 tdeval Exp $	*/
/*	$NetBSD: rf_stripelocks.h,v 1.3 1999/02/05 00:06:18 oster Exp $	*/

/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Mark Holland
 *
 * Permission to use, copy, modify and distribute this software and
 * its documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

/*****************************************************************************
 *
 * stripelocks.h -- Header file for locking stripes.
 *
 * Note that these functions are called from the execution routines of certain
 * DAG Nodes, and so they must be NON-BLOCKING to assure maximum parallelism
 * in the DAG. Accordingly, when a node wants to acquire a lock, it calls
 * AcquireStripeLock, supplying a pointer to a callback function. If the lock
 * is free at the time of the call, 0 is returned, indicating that the lock
 * has been acquired. If the lock is not free, 1 is returned, and a copy of
 * the function pointer and argument are held in the lock table. When the
 * lock becomes free, the callback function is invoked.
 *
 *****************************************************************************/

#ifndef	_RF__RF_STRIPELOCKS_H_
#define	_RF__RF_STRIPELOCKS_H_

#include <sys/buf.h>

#include "rf_types.h"
#include "rf_threadstuff.h"
#include "rf_general.h"

struct RF_LockReqDesc_s {
	RF_IoType_t		  type;		/* Read or write. */
	RF_int64		  start, stop;	/*
						 * Start and end of range to
						 * be locked.
						 */
	RF_int64		  start2, stop2;/*
						 * Start and end of 2nd range
						 * to be locked.
						 */
	void			(*cbFunc) (struct buf *);
						/* Callback function. */
	void			 *cbArg;	/*
						 * Argument to callback
						 * function.
						 */
	RF_LockReqDesc_t	 *next;		/* Next element in chain. */
	RF_LockReqDesc_t	 *templink;	/*
						 * For making short-lived lists
						 * of request descriptors.
						 */
};

#define	RF_ASSERT_VALID_LOCKREQ(_lr_)	do {				\
	RF_ASSERT(RF_IO_IS_R_OR_W((_lr_)->type));			\
} while (0)

struct RF_StripeLockDesc_s {
	RF_StripeNum_t		 stripeID;	/* The stripe ID. */
	RF_LockReqDesc_t	*granted;	/*
						 * Unordered list of granted
						 * requests.
						 */
	RF_LockReqDesc_t	*waitersH;	/* FIFO queue of all waiting
						 * reqs, both read and write
						 * (Head and Tail).
						 */
	RF_LockReqDesc_t	*waitersT;
	int			 nWriters;	/*
						 * Number of writers either
						 * granted or waiting.
						 */
	RF_StripeLockDesc_t	*next;		/*
						 * For hash table collision
						 * resolution.
						 */
};

struct RF_LockTableEntry_s {
	RF_DECLARE_MUTEX	(mutex);	/* Mutex on this hash chain. */
	RF_StripeLockDesc_t	*descList;	/*
						 * Hash chain of lock
						 * descriptors.
						 */
};

/*
 * Initializes a stripe lock descriptor. _defSize is the number of sectors
 * that we lock when there is no parity information in the ASM (e.g. RAID0).
 */

#define RF_INIT_LOCK_REQ_DESC(_lrd, _typ, _cbf, _cba, _asm, _defSize)	\
do {									\
	(_lrd).type    = _typ;						\
	(_lrd).start2  = -1;						\
	(_lrd).stop2   = -1;						\
	if ((_asm)->parityInfo) {					\
		(_lrd).start = (_asm)->parityInfo->startSector;		\
		(_lrd).stop  = (_asm)->parityInfo->startSector +	\
		    (_asm)->parityInfo->numSector-1;			\
		if ((_asm)->parityInfo->next) {				\
			(_lrd).start2  =				\
			    (_asm)->parityInfo->next->startSector;	\
			(_lrd).stop2   =				\
			    (_asm)->parityInfo->next->startSector +	\
			    (_asm)->parityInfo->next->numSector-1;	\
		}							\
	} else {							\
		(_lrd).start = 0;					\
		(_lrd).stop  = (_defSize);				\
	}								\
	(_lrd).templink= NULL;						\
	(_lrd).cbFunc  = (_cbf);					\
	(_lrd).cbArg   = (void *) (_cba);				\
} while (0)

int  rf_ConfigureStripeLockFreeList(RF_ShutdownList_t **);
RF_LockTableEntry_t *rf_MakeLockTable(void);
void rf_ShutdownStripeLocks(RF_LockTableEntry_t *);
int  rf_ConfigureStripeLocks(RF_ShutdownList_t **, RF_Raid_t *, RF_Config_t *);
int  rf_AcquireStripeLock(RF_LockTableEntry_t *, RF_StripeNum_t,
	RF_LockReqDesc_t *);
void rf_ReleaseStripeLock(RF_LockTableEntry_t *, RF_StripeNum_t,
	RF_LockReqDesc_t *);

#endif	/* !_RF__RF_STRIPELOCKS_H_ */