/*      $NetBSD: rf_raid5_rotatedspare.c,v 1.14 2019/02/09 03:34:00 christos Exp $      */
/*
* Copyright (c) 1995 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Khalil Amiri
*
* 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  [email protected]
*  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.
*/

/**************************************************************************
*
* rf_raid5_rotated_spare.c -- implements RAID Level 5 with rotated sparing
*
**************************************************************************/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rf_raid5_rotatedspare.c,v 1.14 2019/02/09 03:34:00 christos Exp $");

#include "rf_archs.h"

#if RF_INCLUDE_RAID5_RS > 0

#include "rf_raid.h"
#include "rf_raid5.h"
#include "rf_dag.h"
#include "rf_dagutils.h"
#include "rf_dagfuncs.h"
#include "rf_general.h"
#include "rf_utils.h"
#include "rf_raid5_rotatedspare.h"

typedef struct RF_Raid5RSConfigInfo_s {
       RF_RowCol_t **stripeIdentifier; /* filled in at config time & used by
                                        * IdentifyStripe */
}       RF_Raid5RSConfigInfo_t;

int
rf_ConfigureRAID5_RS(
   RF_ShutdownList_t ** listp,
   RF_Raid_t * raidPtr,
   RF_Config_t * cfgPtr)
{
       RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
       RF_Raid5RSConfigInfo_t *info;
       RF_RowCol_t i, j, startdisk;

       /* create a RAID level 5 configuration structure */
       info = RF_MallocAndAdd(sizeof(*info), raidPtr->cleanupList);
       if (info == NULL)
               return (ENOMEM);
       layoutPtr->layoutSpecificInfo = (void *) info;

       RF_ASSERT(raidPtr->numCol >= 3);

       /* the stripe identifier must identify the disks in each stripe, IN
        * THE ORDER THAT THEY APPEAR IN THE STRIPE. */
       info->stripeIdentifier = rf_make_2d_array(raidPtr->numCol, raidPtr->numCol, raidPtr->cleanupList);
       if (info->stripeIdentifier == NULL)
               return (ENOMEM);
       startdisk = 0;
       for (i = 0; i < raidPtr->numCol; i++) {
               for (j = 0; j < raidPtr->numCol; j++) {
                       info->stripeIdentifier[i][j] = (startdisk + j) % raidPtr->numCol;
               }
               if ((--startdisk) < 0)
                       startdisk = raidPtr->numCol - 1;
       }

       /* fill in the remaining layout parameters */
       layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
       layoutPtr->numDataCol = raidPtr->numCol - 2;
       layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
       layoutPtr->numParityCol = 1;
       layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk;
       raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit;

       raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk * layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;

       return (0);
}

RF_ReconUnitCount_t
rf_GetNumSpareRUsRAID5_RS(RF_Raid_t *raidPtr)
{
       return (raidPtr->Layout.stripeUnitsPerDisk / raidPtr->numCol);
}

void
rf_MapSectorRAID5_RS(
   RF_Raid_t * raidPtr,
   RF_RaidAddr_t raidSector,
   RF_RowCol_t * col,
   RF_SectorNum_t * diskSector,
   int remap)
{
       RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;

       if (remap) {
               *col = raidPtr->numCol - 1 - (1 + SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol;
               *col = (*col + 1) % raidPtr->numCol;    /* spare unit is rotated
                                                        * with parity; line
                                                        * above maps to parity */
       } else {
               *col = (SUID + (SUID / raidPtr->Layout.numDataCol)) % raidPtr->numCol;
       }
       *diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
           (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
}

void
rf_MapParityRAID5_RS(
   RF_Raid_t * raidPtr,
   RF_RaidAddr_t raidSector,
   RF_RowCol_t * col,
   RF_SectorNum_t * diskSector,
   int remap)
{
       RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;

       *col = raidPtr->numCol - 1 - (1 + SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol;
       *diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
           (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
       if (remap)
               *col = (*col + 1) % raidPtr->numCol;
}

void
rf_IdentifyStripeRAID5_RS(
   RF_Raid_t * raidPtr,
   RF_RaidAddr_t addr,
   RF_RowCol_t ** diskids)
{
       RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, addr);
       RF_Raid5RSConfigInfo_t *info = (RF_Raid5RSConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;
       *diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];

}

void
rf_MapSIDToPSIDRAID5_RS(
   RF_RaidLayout_t * layoutPtr,
   RF_StripeNum_t stripeID,
   RF_StripeNum_t * psID,
   RF_ReconUnitNum_t * which_ru)
{
       *which_ru = 0;
       *psID = stripeID;
}
#endif /* RF_INCLUDE_RAID5_RS > 0 */

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