1 /*	$NetBSD: rf_declusterPQ.c,v 1.16 2014/03/23 09:30:59 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 1.16 2014/03/23 09:30:59 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 
54 int
rf_ConfigureDeclusteredPQ(RF_ShutdownList_t ** listp,RF_Raid_t * raidPtr,RF_Config_t * cfgPtr)55 rf_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 	RF_MallocAndAdd(info, sizeof(RF_DeclusteredConfigInfo_t), (RF_DeclusteredConfigInfo_t *), 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 
267 int
rf_GetDefaultNumFloatingReconBuffersPQ(RF_Raid_t * raidPtr)268 rf_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 
276 void
rf_MapSectorDeclusteredPQ(RF_Raid_t * raidPtr,RF_RaidAddr_t raidSector,RF_RowCol_t * col,RF_SectorNum_t * diskSector,int remap)277 rf_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 
343 void
rf_MapParityDeclusteredPQ(RF_Raid_t * raidPtr,RF_RaidAddr_t raidSector,RF_RowCol_t * col,RF_SectorNum_t * diskSector,int remap)344 rf_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 
393 void
rf_MapQDeclusteredPQ(RF_Raid_t * raidPtr,RF_RaidAddr_t raidSector,RF_RowCol_t * col,RF_SectorNum_t * diskSector,int remap)394 rf_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  */
446 void
rf_IdentifyStripeDeclusteredPQ(RF_Raid_t * raidPtr,RF_RaidAddr_t addr,RF_RowCol_t ** diskids)447 rf_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