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      1 /*	$NetBSD: rf_raid5_rotatedspare.c,v 1.14 2019/02/09 03:34:00 christos Exp $	*/
      2 /*
      3  * Copyright (c) 1995 Carnegie-Mellon University.
      4  * All rights reserved.
      5  *
      6  * Author: Khalil Amiri
      7  *
      8  * Permission to use, copy, modify and distribute this software and
      9  * its documentation is hereby granted, provided that both the copyright
     10  * notice and this permission notice appear in all copies of the
     11  * software, derivative works or modified versions, and any portions
     12  * thereof, and that both notices appear in supporting documentation.
     13  *
     14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     16  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     17  *
     18  * Carnegie Mellon requests users of this software to return to
     19  *
     20  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     21  *  School of Computer Science
     22  *  Carnegie Mellon University
     23  *  Pittsburgh PA 15213-3890
     24  *
     25  * any improvements or extensions that they make and grant Carnegie the
     26  * rights to redistribute these changes.
     27  */
     28 
     29 /**************************************************************************
     30  *
     31  * rf_raid5_rotated_spare.c -- implements RAID Level 5 with rotated sparing
     32  *
     33  **************************************************************************/
     34 
     35 #include <sys/cdefs.h>
     36 __KERNEL_RCSID(0, "$NetBSD: rf_raid5_rotatedspare.c,v 1.14 2019/02/09 03:34:00 christos Exp $");
     37 
     38 #include "rf_archs.h"
     39 
     40 #if RF_INCLUDE_RAID5_RS > 0
     41 
     42 #include "rf_raid.h"
     43 #include "rf_raid5.h"
     44 #include "rf_dag.h"
     45 #include "rf_dagutils.h"
     46 #include "rf_dagfuncs.h"
     47 #include "rf_general.h"
     48 #include "rf_utils.h"
     49 #include "rf_raid5_rotatedspare.h"
     50 
     51 typedef struct RF_Raid5RSConfigInfo_s {
     52 	RF_RowCol_t **stripeIdentifier;	/* filled in at config time & used by
     53 					 * IdentifyStripe */
     54 }       RF_Raid5RSConfigInfo_t;
     55 
     56 int
     57 rf_ConfigureRAID5_RS(
     58     RF_ShutdownList_t ** listp,
     59     RF_Raid_t * raidPtr,
     60     RF_Config_t * cfgPtr)
     61 {
     62 	RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
     63 	RF_Raid5RSConfigInfo_t *info;
     64 	RF_RowCol_t i, j, startdisk;
     65 
     66 	/* create a RAID level 5 configuration structure */
     67 	info = RF_MallocAndAdd(sizeof(*info), raidPtr->cleanupList);
     68 	if (info == NULL)
     69 		return (ENOMEM);
     70 	layoutPtr->layoutSpecificInfo = (void *) info;
     71 
     72 	RF_ASSERT(raidPtr->numCol >= 3);
     73 
     74 	/* the stripe identifier must identify the disks in each stripe, IN
     75 	 * THE ORDER THAT THEY APPEAR IN THE STRIPE. */
     76 	info->stripeIdentifier = rf_make_2d_array(raidPtr->numCol, raidPtr->numCol, raidPtr->cleanupList);
     77 	if (info->stripeIdentifier == NULL)
     78 		return (ENOMEM);
     79 	startdisk = 0;
     80 	for (i = 0; i < raidPtr->numCol; i++) {
     81 		for (j = 0; j < raidPtr->numCol; j++) {
     82 			info->stripeIdentifier[i][j] = (startdisk + j) % raidPtr->numCol;
     83 		}
     84 		if ((--startdisk) < 0)
     85 			startdisk = raidPtr->numCol - 1;
     86 	}
     87 
     88 	/* fill in the remaining layout parameters */
     89 	layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
     90 	layoutPtr->numDataCol = raidPtr->numCol - 2;
     91 	layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
     92 	layoutPtr->numParityCol = 1;
     93 	layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk;
     94 	raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit;
     95 
     96 	raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk * layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
     97 
     98 	return (0);
     99 }
    100 
    101 RF_ReconUnitCount_t
    102 rf_GetNumSpareRUsRAID5_RS(RF_Raid_t *raidPtr)
    103 {
    104 	return (raidPtr->Layout.stripeUnitsPerDisk / raidPtr->numCol);
    105 }
    106 
    107 void
    108 rf_MapSectorRAID5_RS(
    109     RF_Raid_t * raidPtr,
    110     RF_RaidAddr_t raidSector,
    111     RF_RowCol_t * col,
    112     RF_SectorNum_t * diskSector,
    113     int remap)
    114 {
    115 	RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
    116 
    117 	if (remap) {
    118 		*col = raidPtr->numCol - 1 - (1 + SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol;
    119 		*col = (*col + 1) % raidPtr->numCol;	/* spare unit is rotated
    120 							 * with parity; line
    121 							 * above maps to parity */
    122 	} else {
    123 		*col = (SUID + (SUID / raidPtr->Layout.numDataCol)) % raidPtr->numCol;
    124 	}
    125 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
    126 	    (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    127 }
    128 
    129 void
    130 rf_MapParityRAID5_RS(
    131     RF_Raid_t * raidPtr,
    132     RF_RaidAddr_t raidSector,
    133     RF_RowCol_t * col,
    134     RF_SectorNum_t * diskSector,
    135     int remap)
    136 {
    137 	RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
    138 
    139 	*col = raidPtr->numCol - 1 - (1 + SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol;
    140 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
    141 	    (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    142 	if (remap)
    143 		*col = (*col + 1) % raidPtr->numCol;
    144 }
    145 
    146 void
    147 rf_IdentifyStripeRAID5_RS(
    148     RF_Raid_t * raidPtr,
    149     RF_RaidAddr_t addr,
    150     RF_RowCol_t ** diskids)
    151 {
    152 	RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, addr);
    153 	RF_Raid5RSConfigInfo_t *info = (RF_Raid5RSConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;
    154 	*diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
    155 
    156 }
    157 
    158 void
    159 rf_MapSIDToPSIDRAID5_RS(
    160     RF_RaidLayout_t * layoutPtr,
    161     RF_StripeNum_t stripeID,
    162     RF_StripeNum_t * psID,
    163     RF_ReconUnitNum_t * which_ru)
    164 {
    165 	*which_ru = 0;
    166 	*psID = stripeID;
    167 }
    168 #endif /* RF_INCLUDE_RAID5_RS > 0 */
    169