1/*	$NetBSD: rf_declusterPQ.c,v 1.17 2019/02/09 03:34:00 christos Exp $	*/
2/*
3 * Copyright (c) 1995 Carnegie-Mellon University.
4 * All rights reserved.
5 *
6 * Authors: Daniel Stodolsky, Mark Holland, Jim Zelenka
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@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 * rf_declusterPQ.c
31 *
32 * mapping code for declustered P & Q or declustered EvenOdd
33 * much code borrowed from rf_decluster.c
34 *
35 *--------------------------------------------------*/
36
37#include <sys/cdefs.h>
38__KERNEL_RCSID(0, "$NetBSD: rf_declusterPQ.c,v 1.17 2019/02/09 03:34:00 christos Exp $");
39
40#include <dev/raidframe/raidframevar.h>
41
42#include "rf_archs.h"
43#include "rf_raid.h"
44#include "rf_decluster.h"
45#include "rf_declusterPQ.h"
46#include "rf_debugMem.h"
47#include "rf_utils.h"
48#include "rf_alloclist.h"
49#include "rf_general.h"
50
51#if (RF_INCLUDE_PARITY_DECLUSTERING_PQ > 0) || (RF_INCLUDE_EVENODD > 0)
52/* configuration code */
53
54int
55rf_ConfigureDeclusteredPQ(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr,
56			  RF_Config_t *cfgPtr)
57{
58	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
59	int     b, v, k, r;	/* block design params */
60	int     i, j, l;
61	int    *first_avail_slot;
62	int     complete_FT_count, SUID;
63	RF_DeclusteredConfigInfo_t *info;
64	int     numCompleteFullTablesPerDisk;
65	int     PUsPerDisk, spareRegionDepthInPUs, numCompleteSpareRegionsPerDisk = 0,
66	        extraPUsPerDisk;
67	int     totSparePUsPerDisk;
68	int     diskOffsetOfLastFullTableInSUs, SpareSpaceInSUs;
69	char   *cfgBuf = (char *) (cfgPtr->layoutSpecific);
70
71	cfgBuf += RF_SPAREMAP_NAME_LEN;
72
73	b = *((int *) cfgBuf);
74	cfgBuf += sizeof(int);
75	v = *((int *) cfgBuf);
76	cfgBuf += sizeof(int);
77	k = *((int *) cfgBuf);
78	cfgBuf += sizeof(int);
79	r = *((int *) cfgBuf);
80	cfgBuf += sizeof(int);
81	cfgBuf += sizeof(int);
82	raidPtr->noRotate = *((int *) cfgBuf);
83	cfgBuf += sizeof(int);
84
85	if (k <= 2) {
86		printf("RAIDFRAME: k=%d, minimum value 2\n", k);
87		return (EINVAL);
88	}
89	/* 1. create layout specific structure */
90	info = RF_MallocAndAdd(sizeof(*info), raidPtr->cleanupList);
91	if (info == NULL)
92		return (ENOMEM);
93	layoutPtr->layoutSpecificInfo = (void *) info;
94
95	/* the sparemaps are generated assuming that parity is rotated, so we
96	 * issue a warning if both distributed sparing and no-rotate are on at
97	 * the same time */
98	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE) && raidPtr->noRotate) {
99		RF_ERRORMSG("Warning:  distributed sparing specified without parity rotation.\n");
100	}
101	if (raidPtr->numCol != v) {
102		RF_ERRORMSG2("RAID: config error: table element count (%d) not equal to no. of cols (%d)\n", v, raidPtr->numCol);
103		return (EINVAL);
104	}
105	/* 3.  set up the values used in devRaidMap */
106	info->BlocksPerTable = b;
107	info->NumParityReps = info->groupSize = k;
108	info->PUsPerBlock = k - 2;	/* PQ */
109	info->SUsPerTable = b * info->PUsPerBlock * layoutPtr->SUsPerPU;	/* b blks, k-1 SUs each */
110	info->SUsPerFullTable = k * info->SUsPerTable;	/* rot k times */
111	info->SUsPerBlock = info->PUsPerBlock * layoutPtr->SUsPerPU;
112	info->TableDepthInPUs = (b * k) / v;
113	info->FullTableDepthInPUs = info->TableDepthInPUs * k;	/* k repetitions */
114
115	/* used only in distributed sparing case */
116	info->FullTablesPerSpareRegion = (v - 1) / rf_gcd(r, v - 1);	/* (v-1)/gcd fulltables */
117	info->TablesPerSpareRegion = k * info->FullTablesPerSpareRegion;
118	info->SpareSpaceDepthPerRegionInSUs = (r * info->TablesPerSpareRegion / (v - 1)) * layoutPtr->SUsPerPU;
119
120	/* check to make sure the block design is sufficiently small */
121	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
122		if (info->FullTableDepthInPUs * layoutPtr->SUsPerPU + info->SpareSpaceDepthPerRegionInSUs > layoutPtr->stripeUnitsPerDisk) {
123			RF_ERRORMSG3("RAID: config error: Full Table depth (%d) + Spare Space (%d) larger than disk size (%d) (BD too big)\n",
124			    (int) info->FullTableDepthInPUs,
125			    (int) info->SpareSpaceDepthPerRegionInSUs,
126			    (int) layoutPtr->stripeUnitsPerDisk);
127			return (EINVAL);
128		}
129	} else {
130		if (info->TableDepthInPUs * layoutPtr->SUsPerPU > layoutPtr->stripeUnitsPerDisk) {
131			RF_ERRORMSG2("RAID: config error: Table depth (%d) larger than disk size (%d) (BD too big)\n",
132			    (int) (info->TableDepthInPUs * layoutPtr->SUsPerPU),
133			    (int) layoutPtr->stripeUnitsPerDisk);
134			return (EINVAL);
135		}
136	}
137
138
139	/* compute the size of each disk, and the number of tables in the last
140	 * fulltable (which need not be complete) */
141	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
142
143		PUsPerDisk = layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU;
144		spareRegionDepthInPUs = (info->TablesPerSpareRegion * info->TableDepthInPUs +
145		    (info->TablesPerSpareRegion * info->TableDepthInPUs) / (v - 1));
146		info->SpareRegionDepthInSUs = spareRegionDepthInPUs * layoutPtr->SUsPerPU;
147
148		numCompleteSpareRegionsPerDisk = PUsPerDisk / spareRegionDepthInPUs;
149		info->NumCompleteSRs = numCompleteSpareRegionsPerDisk;
150		extraPUsPerDisk = PUsPerDisk % spareRegionDepthInPUs;
151
152		/* assume conservatively that we need the full amount of spare
153		 * space in one region in order to provide spares for the
154		 * partial spare region at the end of the array.  We set "i"
155		 * to the number of tables in the partial spare region.  This
156		 * may actually include some fulltables. */
157		extraPUsPerDisk -= (info->SpareSpaceDepthPerRegionInSUs / layoutPtr->SUsPerPU);
158		if (extraPUsPerDisk <= 0)
159			i = 0;
160		else
161			i = extraPUsPerDisk / info->TableDepthInPUs;
162
163		complete_FT_count = /* raidPtr->numRow */ 1 * (numCompleteSpareRegionsPerDisk * (info->TablesPerSpareRegion / k) + i / k);
164		info->FullTableLimitSUID = complete_FT_count * info->SUsPerFullTable;
165		info->ExtraTablesPerDisk = i % k;
166
167		/* note that in the last spare region, the spare space is
168		 * complete even though data/parity space is not */
169		totSparePUsPerDisk = (numCompleteSpareRegionsPerDisk + 1) * (info->SpareSpaceDepthPerRegionInSUs / layoutPtr->SUsPerPU);
170		info->TotSparePUsPerDisk = totSparePUsPerDisk;
171
172		layoutPtr->stripeUnitsPerDisk =
173		    ((complete_FT_count / /* raidPtr->numRow*/ 1) * info->FullTableDepthInPUs +	/* data & parity space */
174		    info->ExtraTablesPerDisk * info->TableDepthInPUs +
175		    totSparePUsPerDisk	/* spare space */
176		    ) * layoutPtr->SUsPerPU;
177		layoutPtr->dataStripeUnitsPerDisk =
178		    (complete_FT_count * info->FullTableDepthInPUs + info->ExtraTablesPerDisk * info->TableDepthInPUs)
179		    * layoutPtr->SUsPerPU * (k - 1) / k;
180
181	} else {
182		/* non-dist spare case:  force each disk to contain an
183		 * integral number of tables */
184		layoutPtr->stripeUnitsPerDisk /= (info->TableDepthInPUs * layoutPtr->SUsPerPU);
185		layoutPtr->stripeUnitsPerDisk *= (info->TableDepthInPUs * layoutPtr->SUsPerPU);
186
187		/* compute the number of tables in the last fulltable, which
188		 * need not be complete */
189		complete_FT_count =
190		((layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU) / info->FullTableDepthInPUs) * /* raidPtr->numRow */ 1;
191
192		info->FullTableLimitSUID = complete_FT_count * info->SUsPerFullTable;
193		info->ExtraTablesPerDisk =
194		    ((layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU) / info->TableDepthInPUs) % k;
195	}
196
197	raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit;
198
199	/* find the disk offset of the stripe unit where the last fulltable
200	 * starts */
201	numCompleteFullTablesPerDisk = complete_FT_count / /* raidPtr->numRow */ 1;
202	diskOffsetOfLastFullTableInSUs = numCompleteFullTablesPerDisk * info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
203	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
204		SpareSpaceInSUs = numCompleteSpareRegionsPerDisk * info->SpareSpaceDepthPerRegionInSUs;
205		diskOffsetOfLastFullTableInSUs += SpareSpaceInSUs;
206		info->DiskOffsetOfLastSpareSpaceChunkInSUs =
207		    diskOffsetOfLastFullTableInSUs + info->ExtraTablesPerDisk * info->TableDepthInPUs * layoutPtr->SUsPerPU;
208	}
209	info->DiskOffsetOfLastFullTableInSUs = diskOffsetOfLastFullTableInSUs;
210	info->numCompleteFullTablesPerDisk = numCompleteFullTablesPerDisk;
211
212	/* 4.  create and initialize the lookup tables */
213	info->LayoutTable = rf_make_2d_array(b, k, raidPtr->cleanupList);
214	if (info->LayoutTable == NULL)
215		return (ENOMEM);
216	info->OffsetTable = rf_make_2d_array(b, k, raidPtr->cleanupList);
217	if (info->OffsetTable == NULL)
218		return (ENOMEM);
219	info->BlockTable = rf_make_2d_array(info->TableDepthInPUs * layoutPtr->SUsPerPU, raidPtr->numCol, raidPtr->cleanupList);
220	if (info->BlockTable == NULL)
221		return (ENOMEM);
222
223	first_avail_slot = (int *) rf_make_1d_array(v, NULL);
224	if (first_avail_slot == NULL)
225		return (ENOMEM);
226
227	for (i = 0; i < b; i++)
228		for (j = 0; j < k; j++)
229			info->LayoutTable[i][j] = *cfgBuf++;
230
231	/* initialize offset table */
232	for (i = 0; i < b; i++)
233		for (j = 0; j < k; j++) {
234			info->OffsetTable[i][j] = first_avail_slot[info->LayoutTable[i][j]];
235			first_avail_slot[info->LayoutTable[i][j]]++;
236		}
237
238	/* initialize block table */
239	for (SUID = l = 0; l < layoutPtr->SUsPerPU; l++) {
240		for (i = 0; i < b; i++) {
241			for (j = 0; j < k; j++) {
242				info->BlockTable[(info->OffsetTable[i][j] * layoutPtr->SUsPerPU) + l]
243				    [info->LayoutTable[i][j]] = SUID;
244			}
245			SUID++;
246		}
247	}
248
249	rf_free_1d_array(first_avail_slot, v);
250
251	/* 5.  set up the remaining redundant-but-useful parameters */
252
253	raidPtr->totalSectors = (k * complete_FT_count + /* raidPtr->numRow */ 1 * info->ExtraTablesPerDisk) *
254	    info->SUsPerTable * layoutPtr->sectorsPerStripeUnit;
255	layoutPtr->numStripe = (raidPtr->totalSectors / layoutPtr->sectorsPerStripeUnit) / (k - 2);
256
257	/* strange evaluation order below to try and minimize overflow
258	 * problems */
259
260	layoutPtr->dataSectorsPerStripe = (k - 2) * layoutPtr->sectorsPerStripeUnit;
261	layoutPtr->numDataCol = k - 2;
262	layoutPtr->numParityCol = 2;
263
264	return (0);
265}
266
267int
268rf_GetDefaultNumFloatingReconBuffersPQ(RF_Raid_t *raidPtr)
269{
270	int     def_decl;
271
272	def_decl = rf_GetDefaultNumFloatingReconBuffersDeclustered(raidPtr);
273	return (RF_MAX(3 * raidPtr->numCol, def_decl));
274}
275
276void
277rf_MapSectorDeclusteredPQ(RF_Raid_t *raidPtr, RF_RaidAddr_t raidSector,
278			  RF_RowCol_t *col,
279			  RF_SectorNum_t *diskSector, int remap)
280{
281	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
282	RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
283	RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
284	RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
285	RF_StripeNum_t BlockID, BlockOffset, RepIndex;
286	RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
287	RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
288	RF_StripeNum_t base_suid = 0, outSU, SpareRegion = 0, SpareSpace = 0;
289
290	rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
291
292	FullTableID = SUID / sus_per_fulltable;	/* fulltable ID within array
293						 * (across rows) */
294	FullTableID /= /* raidPtr->numRow */ 1;	/* convert to fulltable ID on this
295					 * disk */
296	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
297		SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
298		SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
299	}
300	FullTableOffset = SUID % sus_per_fulltable;
301	TableID = FullTableOffset / info->SUsPerTable;
302	TableOffset = FullTableOffset - TableID * info->SUsPerTable;
303	BlockID = TableOffset / info->PUsPerBlock;
304	BlockOffset = TableOffset - BlockID * info->PUsPerBlock;
305	BlockID %= info->BlocksPerTable;
306	RF_ASSERT(BlockOffset < info->groupSize - 2);
307	/*
308           TableIDs go from 0 .. GroupSize-1 inclusive.
309           PUsPerBlock is k-2.
310           We want the tableIDs to rotate from the
311           right, so use GroupSize
312           */
313	RepIndex = info->groupSize - 1 - TableID;
314	RF_ASSERT(RepIndex >= 0);
315	if (!raidPtr->noRotate) {
316		if (TableID == 0)
317			BlockOffset++;	/* P on last drive, Q on first */
318		else
319			BlockOffset += ((BlockOffset >= RepIndex) ? 2 : 0);	/* skip over PQ */
320		RF_ASSERT(BlockOffset < info->groupSize);
321		*col = info->LayoutTable[BlockID][BlockOffset];
322	}
323	/* remap to distributed spare space if indicated */
324	if (remap) {
325		rf_remap_to_spare_space(layoutPtr, info, FullTableID, TableID, BlockID, (base_suid) ? 1 : 0, SpareRegion, col, &outSU);
326	} else {
327
328		outSU = base_suid;
329		outSU += FullTableID * fulltable_depth;	/* offs to strt of FT */
330		outSU += SpareSpace;	/* skip rsvd spare space */
331		outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU;	/* offs to strt of tble */
332		outSU += info->OffsetTable[BlockID][BlockOffset] * layoutPtr->SUsPerPU;	/* offs to the PU */
333	}
334	outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock);	/* offs to the SU within
335										 * a PU */
336
337	/* convert SUs to sectors, and, if not aligned to SU boundary, add in
338	 * offset to sector */
339	*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
340}
341
342
343void
344rf_MapParityDeclusteredPQ(RF_Raid_t *raidPtr, RF_RaidAddr_t raidSector,
345			  RF_RowCol_t *col,
346			  RF_SectorNum_t *diskSector, int remap)
347{
348	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
349	RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
350	RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
351	RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
352	RF_StripeNum_t BlockID, RepIndex;
353	RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
354	RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
355	RF_StripeNum_t base_suid = 0, outSU, SpareRegion, SpareSpace = 0;
356
357	rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
358
359	/* compute row & (possibly) spare space exactly as before */
360	FullTableID = SUID / sus_per_fulltable;
361	FullTableID /= /* raidPtr->numRow */ 1;	/* convert to fulltable ID on this
362					 * disk */
363	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
364		SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
365		SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
366	}
367	/* compute BlockID and RepIndex exactly as before */
368	FullTableOffset = SUID % sus_per_fulltable;
369	TableID = FullTableOffset / info->SUsPerTable;
370	TableOffset = FullTableOffset - TableID * info->SUsPerTable;
371	BlockID = TableOffset / info->PUsPerBlock;
372	BlockID %= info->BlocksPerTable;
373
374	/* the parity block is in the position indicated by RepIndex */
375	RepIndex = (raidPtr->noRotate) ? info->PUsPerBlock : info->groupSize - 1 - TableID;
376	*col = info->LayoutTable[BlockID][RepIndex];
377
378	if (remap)
379		RF_PANIC();
380
381	/* compute sector as before, except use RepIndex instead of
382	 * BlockOffset */
383	outSU = base_suid;
384	outSU += FullTableID * fulltable_depth;
385	outSU += SpareSpace;	/* skip rsvd spare space */
386	outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU;
387	outSU += info->OffsetTable[BlockID][RepIndex] * layoutPtr->SUsPerPU;
388	outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock);
389
390	*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
391}
392
393void
394rf_MapQDeclusteredPQ(RF_Raid_t *raidPtr, RF_RaidAddr_t raidSector,
395		     RF_RowCol_t *col,
396		     RF_SectorNum_t *diskSector, int remap)
397{
398	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
399	RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
400	RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
401	RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
402	RF_StripeNum_t BlockID, RepIndex, RepIndexQ;
403	RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
404	RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
405	RF_StripeNum_t base_suid = 0, outSU, SpareRegion, SpareSpace = 0;
406
407	rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
408
409	/* compute row & (possibly) spare space exactly as before */
410	FullTableID = SUID / sus_per_fulltable;
411	FullTableID /= /* raidPtr->numRow */ 1;	/* convert to fulltable ID on this
412					 * disk */
413	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
414		SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
415		SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
416	}
417	/* compute BlockID and RepIndex exactly as before */
418	FullTableOffset = SUID % sus_per_fulltable;
419	TableID = FullTableOffset / info->SUsPerTable;
420	TableOffset = FullTableOffset - TableID * info->SUsPerTable;
421	BlockID = TableOffset / info->PUsPerBlock;
422	BlockID %= info->BlocksPerTable;
423
424	/* the q block is in the position indicated by RepIndex */
425	RepIndex = (raidPtr->noRotate) ? info->PUsPerBlock : info->groupSize - 1 - TableID;
426	RepIndexQ = ((RepIndex == (info->groupSize - 1)) ? 0 : RepIndex + 1);
427	*col = info->LayoutTable[BlockID][RepIndexQ];
428
429	if (remap)
430		RF_PANIC();
431
432	/* compute sector as before, except use RepIndex instead of
433	 * BlockOffset */
434	outSU = base_suid;
435	outSU += FullTableID * fulltable_depth;
436	outSU += SpareSpace;	/* skip rsvd spare space */
437	outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU;
438	outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock);
439
440	outSU += info->OffsetTable[BlockID][RepIndexQ] * layoutPtr->SUsPerPU;
441	*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
442}
443/* returns an array of ints identifying the disks that comprise the stripe containing the indicated address.
444 * the caller must _never_ attempt to modify this array.
445 */
446void
447rf_IdentifyStripeDeclusteredPQ(RF_Raid_t *raidPtr, RF_RaidAddr_t addr,
448			       RF_RowCol_t **diskids)
449{
450	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
451	RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
452	RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
453	RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
454	RF_StripeNum_t base_suid = 0;
455	RF_StripeNum_t SUID = rf_RaidAddressToStripeUnitID(layoutPtr, addr);
456	RF_StripeNum_t stripeID;
457	int     tableOffset;
458
459	rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
460	stripeID = rf_StripeUnitIDToStripeID(layoutPtr, SUID);	/* find stripe offset
461								 * into array */
462	tableOffset = (stripeID % info->BlocksPerTable);	/* find offset into
463								 * block design table */
464	*diskids = info->LayoutTable[tableOffset];
465}
466#endif /* (RF_INCLUDE_PARITY_DECLUSTERING_PQ > 0) || (RF_INCLUDE_EVENODD > 0) */
467