1 /*
2  *  Linux MegaRAID driver for SAS based RAID controllers
3  *
4  *  Copyright (c) 2009-2012  LSI Corporation.
5  *
6  *  This program is free software; you can redistribute it and/or
7  *  modify it under the terms of the GNU General Public License
8  *  as published by the Free Software Foundation; either version 2
9  *  of the License, or (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, write to the Free Software
18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19  *
20  *  FILE: megaraid_sas_fp.c
21  *
22  *  Authors: LSI Corporation
23  *           Sumant Patro
24  *           Varad Talamacki
25  *           Manoj Jose
26  *
27  *  Send feedback to: <megaraidlinux@lsi.com>
28  *
29  *  Mail to: LSI Corporation, 1621 Barber Lane, Milpitas, CA 95035
30  *     ATTN: Linuxraid
31  */
32 
33 #include <linux/kernel.h>
34 #include <linux/types.h>
35 #include <linux/pci.h>
36 #include <linux/list.h>
37 #include <linux/moduleparam.h>
38 #include <linux/module.h>
39 #include <linux/spinlock.h>
40 #include <linux/interrupt.h>
41 #include <linux/delay.h>
42 #include <linux/uio.h>
43 #include <linux/uaccess.h>
44 #include <linux/fs.h>
45 #include <linux/compat.h>
46 #include <linux/blkdev.h>
47 #include <linux/poll.h>
48 
49 #include <scsi/scsi.h>
50 #include <scsi/scsi_cmnd.h>
51 #include <scsi/scsi_device.h>
52 #include <scsi/scsi_host.h>
53 
54 #include "megaraid_sas_fusion.h"
55 #include "megaraid_sas.h"
56 #include <asm/div64.h>
57 
58 #define ABS_DIFF(a, b)   (((a) > (b)) ? ((a) - (b)) : ((b) - (a)))
59 #define MR_LD_STATE_OPTIMAL 3
60 #define FALSE 0
61 #define TRUE 1
62 
63 #define SPAN_DEBUG 0
64 #define SPAN_ROW_SIZE(map, ld, index_) (MR_LdSpanPtrGet(ld, index_, map)->spanRowSize)
65 #define SPAN_ROW_DATA_SIZE(map_, ld, index_)   (MR_LdSpanPtrGet(ld, index_, map)->spanRowDataSize)
66 #define SPAN_INVALID  0xff
67 
68 /* Prototypes */
69 void mr_update_load_balance_params(struct MR_FW_RAID_MAP_ALL *map,
70 	struct LD_LOAD_BALANCE_INFO *lbInfo);
71 
72 static void mr_update_span_set(struct MR_FW_RAID_MAP_ALL *map,
73 	PLD_SPAN_INFO ldSpanInfo);
74 static u8 mr_spanset_get_phy_params(struct megasas_instance *instance, u32 ld,
75 	u64 stripRow, u16 stripRef, struct IO_REQUEST_INFO *io_info,
76 	struct RAID_CONTEXT *pRAID_Context, struct MR_FW_RAID_MAP_ALL *map);
77 static u64 get_row_from_strip(struct megasas_instance *instance, u32 ld,
78 	u64 strip, struct MR_FW_RAID_MAP_ALL *map);
79 
80 u32 mega_mod64(u64 dividend, u32 divisor)
81 {
82 	u64 d;
83 	u32 remainder;
84 
85 	if (!divisor)
86 		printk(KERN_ERR "megasas : DIVISOR is zero, in div fn\n");
87 	d = dividend;
88 	remainder = do_div(d, divisor);
89 	return remainder;
90 }
91 
92 /**
93  * @param dividend    : Dividend
94  * @param divisor    : Divisor
95  *
96  * @return quotient
97  **/
98 u64 mega_div64_32(uint64_t dividend, uint32_t divisor)
99 {
100 	u32 remainder;
101 	u64 d;
102 
103 	if (!divisor)
104 		printk(KERN_ERR "megasas : DIVISOR is zero in mod fn\n");
105 
106 	d = dividend;
107 	remainder = do_div(d, divisor);
108 
109 	return d;
110 }
111 
112 struct MR_LD_RAID *MR_LdRaidGet(u32 ld, struct MR_FW_RAID_MAP_ALL *map)
113 {
114 	return &map->raidMap.ldSpanMap[ld].ldRaid;
115 }
116 
117 static struct MR_SPAN_BLOCK_INFO *MR_LdSpanInfoGet(u32 ld,
118 						   struct MR_FW_RAID_MAP_ALL
119 						   *map)
120 {
121 	return &map->raidMap.ldSpanMap[ld].spanBlock[0];
122 }
123 
124 static u8 MR_LdDataArmGet(u32 ld, u32 armIdx, struct MR_FW_RAID_MAP_ALL *map)
125 {
126 	return map->raidMap.ldSpanMap[ld].dataArmMap[armIdx];
127 }
128 
129 static u16 MR_ArPdGet(u32 ar, u32 arm, struct MR_FW_RAID_MAP_ALL *map)
130 {
131 	return map->raidMap.arMapInfo[ar].pd[arm];
132 }
133 
134 static u16 MR_LdSpanArrayGet(u32 ld, u32 span, struct MR_FW_RAID_MAP_ALL *map)
135 {
136 	return map->raidMap.ldSpanMap[ld].spanBlock[span].span.arrayRef;
137 }
138 
139 static u16 MR_PdDevHandleGet(u32 pd, struct MR_FW_RAID_MAP_ALL *map)
140 {
141 	return map->raidMap.devHndlInfo[pd].curDevHdl;
142 }
143 
144 u16 MR_GetLDTgtId(u32 ld, struct MR_FW_RAID_MAP_ALL *map)
145 {
146 	return map->raidMap.ldSpanMap[ld].ldRaid.targetId;
147 }
148 
149 u16 MR_TargetIdToLdGet(u32 ldTgtId, struct MR_FW_RAID_MAP_ALL *map)
150 {
151 	return map->raidMap.ldTgtIdToLd[ldTgtId];
152 }
153 
154 static struct MR_LD_SPAN *MR_LdSpanPtrGet(u32 ld, u32 span,
155 					  struct MR_FW_RAID_MAP_ALL *map)
156 {
157 	return &map->raidMap.ldSpanMap[ld].spanBlock[span].span;
158 }
159 
160 /*
161  * This function will validate Map info data provided by FW
162  */
163 u8 MR_ValidateMapInfo(struct megasas_instance *instance)
164 {
165 	struct fusion_context *fusion = instance->ctrl_context;
166 	struct MR_FW_RAID_MAP_ALL *map = fusion->ld_map[(instance->map_id & 1)];
167 	struct LD_LOAD_BALANCE_INFO *lbInfo = fusion->load_balance_info;
168 	PLD_SPAN_INFO ldSpanInfo = fusion->log_to_span;
169 	struct MR_FW_RAID_MAP *pFwRaidMap = &map->raidMap;
170 
171 	if (pFwRaidMap->totalSize !=
172 	    (sizeof(struct MR_FW_RAID_MAP) -sizeof(struct MR_LD_SPAN_MAP) +
173 	     (sizeof(struct MR_LD_SPAN_MAP) *pFwRaidMap->ldCount))) {
174 		printk(KERN_ERR "megasas: map info structure size 0x%x is not matching with ld count\n",
175 		       (unsigned int)((sizeof(struct MR_FW_RAID_MAP) -
176 				       sizeof(struct MR_LD_SPAN_MAP)) +
177 				      (sizeof(struct MR_LD_SPAN_MAP) *
178 				       pFwRaidMap->ldCount)));
179 		printk(KERN_ERR "megasas: span map %x, pFwRaidMap->totalSize "
180 		       ": %x\n", (unsigned int)sizeof(struct MR_LD_SPAN_MAP),
181 		       pFwRaidMap->totalSize);
182 		return 0;
183 	}
184 
185 	if (instance->UnevenSpanSupport)
186 		mr_update_span_set(map, ldSpanInfo);
187 
188 	mr_update_load_balance_params(map, lbInfo);
189 
190 	return 1;
191 }
192 
193 u32 MR_GetSpanBlock(u32 ld, u64 row, u64 *span_blk,
194 		    struct MR_FW_RAID_MAP_ALL *map)
195 {
196 	struct MR_SPAN_BLOCK_INFO *pSpanBlock = MR_LdSpanInfoGet(ld, map);
197 	struct MR_QUAD_ELEMENT    *quad;
198 	struct MR_LD_RAID         *raid = MR_LdRaidGet(ld, map);
199 	u32                span, j;
200 
201 	for (span = 0; span < raid->spanDepth; span++, pSpanBlock++) {
202 
203 		for (j = 0; j < pSpanBlock->block_span_info.noElements; j++) {
204 			quad = &pSpanBlock->block_span_info.quad[j];
205 
206 			if (quad->diff == 0)
207 				return SPAN_INVALID;
208 			if (quad->logStart <= row  &&  row <= quad->logEnd  &&
209 			    (mega_mod64(row-quad->logStart, quad->diff)) == 0) {
210 				if (span_blk != NULL) {
211 					u64  blk, debugBlk;
212 					blk =
213 						mega_div64_32(
214 							(row-quad->logStart),
215 							quad->diff);
216 					debugBlk = blk;
217 
218 					blk = (blk + quad->offsetInSpan) <<
219 						raid->stripeShift;
220 					*span_blk = blk;
221 				}
222 				return span;
223 			}
224 		}
225 	}
226 	return SPAN_INVALID;
227 }
228 
229 /*
230 ******************************************************************************
231 *
232 * Function to print info about span set created in driver from FW raid map
233 *
234 * Inputs :
235 * map    - LD map
236 * ldSpanInfo - ldSpanInfo per HBA instance
237 */
238 #if SPAN_DEBUG
239 static int getSpanInfo(struct MR_FW_RAID_MAP_ALL *map, PLD_SPAN_INFO ldSpanInfo)
240 {
241 
242 	u8   span;
243 	u32    element;
244 	struct MR_LD_RAID *raid;
245 	LD_SPAN_SET *span_set;
246 	struct MR_QUAD_ELEMENT    *quad;
247 	int ldCount;
248 	u16 ld;
249 
250 	for (ldCount = 0; ldCount < MAX_LOGICAL_DRIVES; ldCount++) {
251 		ld = MR_TargetIdToLdGet(ldCount, map);
252 			if (ld >= MAX_LOGICAL_DRIVES)
253 				continue;
254 		raid = MR_LdRaidGet(ld, map);
255 		dev_dbg(&instance->pdev->dev, "LD %x: span_depth=%x\n",
256 			ld, raid->spanDepth);
257 		for (span = 0; span < raid->spanDepth; span++)
258 			dev_dbg(&instance->pdev->dev, "Span=%x,"
259 			" number of quads=%x\n", span,
260 			map->raidMap.ldSpanMap[ld].spanBlock[span].
261 			block_span_info.noElements);
262 		for (element = 0; element < MAX_QUAD_DEPTH; element++) {
263 			span_set = &(ldSpanInfo[ld].span_set[element]);
264 			if (span_set->span_row_data_width == 0)
265 				break;
266 
267 			dev_dbg(&instance->pdev->dev, "Span Set %x:"
268 				"width=%x, diff=%x\n", element,
269 				(unsigned int)span_set->span_row_data_width,
270 				(unsigned int)span_set->diff);
271 			dev_dbg(&instance->pdev->dev, "logical LBA"
272 				"start=0x%08lx, end=0x%08lx\n",
273 				(long unsigned int)span_set->log_start_lba,
274 				(long unsigned int)span_set->log_end_lba);
275 			dev_dbg(&instance->pdev->dev, "span row start=0x%08lx,"
276 				" end=0x%08lx\n",
277 				(long unsigned int)span_set->span_row_start,
278 				(long unsigned int)span_set->span_row_end);
279 			dev_dbg(&instance->pdev->dev, "data row start=0x%08lx,"
280 				" end=0x%08lx\n",
281 				(long unsigned int)span_set->data_row_start,
282 				(long unsigned int)span_set->data_row_end);
283 			dev_dbg(&instance->pdev->dev, "data strip start=0x%08lx,"
284 				" end=0x%08lx\n",
285 				(long unsigned int)span_set->data_strip_start,
286 				(long unsigned int)span_set->data_strip_end);
287 
288 			for (span = 0; span < raid->spanDepth; span++) {
289 				if (map->raidMap.ldSpanMap[ld].spanBlock[span].
290 					block_span_info.noElements >=
291 					element + 1) {
292 					quad = &map->raidMap.ldSpanMap[ld].
293 						spanBlock[span].block_span_info.
294 						quad[element];
295 				dev_dbg(&instance->pdev->dev, "Span=%x,"
296 					"Quad=%x, diff=%x\n", span,
297 					element, quad->diff);
298 				dev_dbg(&instance->pdev->dev,
299 					"offset_in_span=0x%08lx\n",
300 					(long unsigned int)quad->offsetInSpan);
301 				dev_dbg(&instance->pdev->dev,
302 					"logical start=0x%08lx, end=0x%08lx\n",
303 					(long unsigned int)quad->logStart,
304 					(long unsigned int)quad->logEnd);
305 				}
306 			}
307 		}
308 	}
309 	return 0;
310 }
311 #endif
312 
313 /*
314 ******************************************************************************
315 *
316 * This routine calculates the Span block for given row using spanset.
317 *
318 * Inputs :
319 *    instance - HBA instance
320 *    ld   - Logical drive number
321 *    row        - Row number
322 *    map    - LD map
323 *
324 * Outputs :
325 *
326 *    span          - Span number
327 *    block         - Absolute Block number in the physical disk
328 *    div_error	   - Devide error code.
329 */
330 
331 u32 mr_spanset_get_span_block(struct megasas_instance *instance,
332 		u32 ld, u64 row, u64 *span_blk, struct MR_FW_RAID_MAP_ALL *map)
333 {
334 	struct fusion_context *fusion = instance->ctrl_context;
335 	struct MR_LD_RAID         *raid = MR_LdRaidGet(ld, map);
336 	LD_SPAN_SET *span_set;
337 	struct MR_QUAD_ELEMENT    *quad;
338 	u32    span, info;
339 	PLD_SPAN_INFO ldSpanInfo = fusion->log_to_span;
340 
341 	for (info = 0; info < MAX_QUAD_DEPTH; info++) {
342 		span_set = &(ldSpanInfo[ld].span_set[info]);
343 
344 		if (span_set->span_row_data_width == 0)
345 			break;
346 
347 		if (row > span_set->data_row_end)
348 			continue;
349 
350 		for (span = 0; span < raid->spanDepth; span++)
351 			if (map->raidMap.ldSpanMap[ld].spanBlock[span].
352 				block_span_info.noElements >= info+1) {
353 				quad = &map->raidMap.ldSpanMap[ld].
354 					spanBlock[span].
355 					block_span_info.quad[info];
356 				if (quad->diff == 0)
357 					return SPAN_INVALID;
358 				if (quad->logStart <= row  &&
359 					row <= quad->logEnd  &&
360 					(mega_mod64(row - quad->logStart,
361 						quad->diff)) == 0) {
362 					if (span_blk != NULL) {
363 						u64  blk;
364 						blk = mega_div64_32
365 						    ((row - quad->logStart),
366 						    quad->diff);
367 						blk = (blk + quad->offsetInSpan)
368 							 << raid->stripeShift;
369 						*span_blk = blk;
370 					}
371 					return span;
372 				}
373 			}
374 	}
375 	return SPAN_INVALID;
376 }
377 
378 /*
379 ******************************************************************************
380 *
381 * This routine calculates the row for given strip using spanset.
382 *
383 * Inputs :
384 *    instance - HBA instance
385 *    ld   - Logical drive number
386 *    Strip        - Strip
387 *    map    - LD map
388 *
389 * Outputs :
390 *
391 *    row         - row associated with strip
392 */
393 
394 static u64  get_row_from_strip(struct megasas_instance *instance,
395 	u32 ld, u64 strip, struct MR_FW_RAID_MAP_ALL *map)
396 {
397 	struct fusion_context *fusion = instance->ctrl_context;
398 	struct MR_LD_RAID	*raid = MR_LdRaidGet(ld, map);
399 	LD_SPAN_SET	*span_set;
400 	PLD_SPAN_INFO	ldSpanInfo = fusion->log_to_span;
401 	u32		info, strip_offset, span, span_offset;
402 	u64		span_set_Strip, span_set_Row, retval;
403 
404 	for (info = 0; info < MAX_QUAD_DEPTH; info++) {
405 		span_set = &(ldSpanInfo[ld].span_set[info]);
406 
407 		if (span_set->span_row_data_width == 0)
408 			break;
409 		if (strip > span_set->data_strip_end)
410 			continue;
411 
412 		span_set_Strip = strip - span_set->data_strip_start;
413 		strip_offset = mega_mod64(span_set_Strip,
414 				span_set->span_row_data_width);
415 		span_set_Row = mega_div64_32(span_set_Strip,
416 				span_set->span_row_data_width) * span_set->diff;
417 		for (span = 0, span_offset = 0; span < raid->spanDepth; span++)
418 			if (map->raidMap.ldSpanMap[ld].spanBlock[span].
419 				block_span_info.noElements >= info+1) {
420 				if (strip_offset >=
421 					span_set->strip_offset[span])
422 					span_offset++;
423 				else
424 					break;
425 			}
426 #if SPAN_DEBUG
427 		dev_info(&instance->pdev->dev, "Strip 0x%llx,"
428 			"span_set_Strip 0x%llx, span_set_Row 0x%llx"
429 			"data width 0x%llx span offset 0x%x\n", strip,
430 			(unsigned long long)span_set_Strip,
431 			(unsigned long long)span_set_Row,
432 			(unsigned long long)span_set->span_row_data_width,
433 			span_offset);
434 		dev_info(&instance->pdev->dev, "For strip 0x%llx"
435 			"row is 0x%llx\n", strip,
436 			(unsigned long long) span_set->data_row_start +
437 			(unsigned long long) span_set_Row + (span_offset - 1));
438 #endif
439 		retval = (span_set->data_row_start + span_set_Row +
440 				(span_offset - 1));
441 		return retval;
442 	}
443 	return -1LLU;
444 }
445 
446 
447 /*
448 ******************************************************************************
449 *
450 * This routine calculates the Start Strip for given row using spanset.
451 *
452 * Inputs :
453 *    instance - HBA instance
454 *    ld   - Logical drive number
455 *    row        - Row number
456 *    map    - LD map
457 *
458 * Outputs :
459 *
460 *    Strip         - Start strip associated with row
461 */
462 
463 static u64 get_strip_from_row(struct megasas_instance *instance,
464 		u32 ld, u64 row, struct MR_FW_RAID_MAP_ALL *map)
465 {
466 	struct fusion_context *fusion = instance->ctrl_context;
467 	struct MR_LD_RAID         *raid = MR_LdRaidGet(ld, map);
468 	LD_SPAN_SET *span_set;
469 	struct MR_QUAD_ELEMENT    *quad;
470 	PLD_SPAN_INFO ldSpanInfo = fusion->log_to_span;
471 	u32    span, info;
472 	u64  strip;
473 
474 	for (info = 0; info < MAX_QUAD_DEPTH; info++) {
475 		span_set = &(ldSpanInfo[ld].span_set[info]);
476 
477 		if (span_set->span_row_data_width == 0)
478 			break;
479 		if (row > span_set->data_row_end)
480 			continue;
481 
482 		for (span = 0; span < raid->spanDepth; span++)
483 			if (map->raidMap.ldSpanMap[ld].spanBlock[span].
484 				block_span_info.noElements >= info+1) {
485 				quad = &map->raidMap.ldSpanMap[ld].
486 					spanBlock[span].block_span_info.quad[info];
487 				if (quad->logStart <= row  &&
488 					row <= quad->logEnd  &&
489 					mega_mod64((row - quad->logStart),
490 					quad->diff) == 0) {
491 					strip = mega_div64_32
492 						(((row - span_set->data_row_start)
493 							- quad->logStart),
494 							quad->diff);
495 					strip *= span_set->span_row_data_width;
496 					strip += span_set->data_strip_start;
497 					strip += span_set->strip_offset[span];
498 					return strip;
499 				}
500 			}
501 	}
502 	dev_err(&instance->pdev->dev, "get_strip_from_row"
503 		"returns invalid strip for ld=%x, row=%lx\n",
504 		ld, (long unsigned int)row);
505 	return -1;
506 }
507 
508 /*
509 ******************************************************************************
510 *
511 * This routine calculates the Physical Arm for given strip using spanset.
512 *
513 * Inputs :
514 *    instance - HBA instance
515 *    ld   - Logical drive number
516 *    strip      - Strip
517 *    map    - LD map
518 *
519 * Outputs :
520 *
521 *    Phys Arm         - Phys Arm associated with strip
522 */
523 
524 static u32 get_arm_from_strip(struct megasas_instance *instance,
525 	u32 ld, u64 strip, struct MR_FW_RAID_MAP_ALL *map)
526 {
527 	struct fusion_context *fusion = instance->ctrl_context;
528 	struct MR_LD_RAID         *raid = MR_LdRaidGet(ld, map);
529 	LD_SPAN_SET *span_set;
530 	PLD_SPAN_INFO ldSpanInfo = fusion->log_to_span;
531 	u32    info, strip_offset, span, span_offset, retval;
532 
533 	for (info = 0 ; info < MAX_QUAD_DEPTH; info++) {
534 		span_set = &(ldSpanInfo[ld].span_set[info]);
535 
536 		if (span_set->span_row_data_width == 0)
537 			break;
538 		if (strip > span_set->data_strip_end)
539 			continue;
540 
541 		strip_offset = (uint)mega_mod64
542 				((strip - span_set->data_strip_start),
543 				span_set->span_row_data_width);
544 
545 		for (span = 0, span_offset = 0; span < raid->spanDepth; span++)
546 			if (map->raidMap.ldSpanMap[ld].spanBlock[span].
547 				block_span_info.noElements >= info+1) {
548 				if (strip_offset >=
549 					span_set->strip_offset[span])
550 					span_offset =
551 						span_set->strip_offset[span];
552 				else
553 					break;
554 			}
555 #if SPAN_DEBUG
556 		dev_info(&instance->pdev->dev, "get_arm_from_strip:"
557 			"for ld=0x%x strip=0x%lx arm is  0x%x\n", ld,
558 			(long unsigned int)strip, (strip_offset - span_offset));
559 #endif
560 		retval = (strip_offset - span_offset);
561 		return retval;
562 	}
563 
564 	dev_err(&instance->pdev->dev, "get_arm_from_strip"
565 		"returns invalid arm for ld=%x strip=%lx\n",
566 		ld, (long unsigned int)strip);
567 
568 	return -1;
569 }
570 
571 /* This Function will return Phys arm */
572 u8 get_arm(struct megasas_instance *instance, u32 ld, u8 span, u64 stripe,
573 		struct MR_FW_RAID_MAP_ALL *map)
574 {
575 	struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
576 	/* Need to check correct default value */
577 	u32    arm = 0;
578 
579 	switch (raid->level) {
580 	case 0:
581 	case 5:
582 	case 6:
583 		arm = mega_mod64(stripe, SPAN_ROW_SIZE(map, ld, span));
584 		break;
585 	case 1:
586 		/* start with logical arm */
587 		arm = get_arm_from_strip(instance, ld, stripe, map);
588 		if (arm != -1U)
589 			arm *= 2;
590 		break;
591 	}
592 
593 	return arm;
594 }
595 
596 
597 /*
598 ******************************************************************************
599 *
600 * This routine calculates the arm, span and block for the specified stripe and
601 * reference in stripe using spanset
602 *
603 * Inputs :
604 *
605 *    ld   - Logical drive number
606 *    stripRow        - Stripe number
607 *    stripRef    - Reference in stripe
608 *
609 * Outputs :
610 *
611 *    span          - Span number
612 *    block         - Absolute Block number in the physical disk
613 */
614 static u8 mr_spanset_get_phy_params(struct megasas_instance *instance, u32 ld,
615 		u64 stripRow, u16 stripRef, struct IO_REQUEST_INFO *io_info,
616 		struct RAID_CONTEXT *pRAID_Context,
617 		struct MR_FW_RAID_MAP_ALL *map)
618 {
619 	struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
620 	u32     pd, arRef;
621 	u8      physArm, span;
622 	u64     row;
623 	u8	retval = TRUE;
624 	u8	do_invader = 0;
625 	u64	*pdBlock = &io_info->pdBlock;
626 	u16	*pDevHandle = &io_info->devHandle;
627 	u32	logArm, rowMod, armQ, arm;
628 
629 	if ((instance->pdev->device == PCI_DEVICE_ID_LSI_INVADER ||
630 		instance->pdev->device == PCI_DEVICE_ID_LSI_FURY))
631 		do_invader = 1;
632 
633 	/*Get row and span from io_info for Uneven Span IO.*/
634 	row	    = io_info->start_row;
635 	span	    = io_info->start_span;
636 
637 
638 	if (raid->level == 6) {
639 		logArm = get_arm_from_strip(instance, ld, stripRow, map);
640 		if (logArm == -1U)
641 			return FALSE;
642 		rowMod = mega_mod64(row, SPAN_ROW_SIZE(map, ld, span));
643 		armQ = SPAN_ROW_SIZE(map, ld, span) - 1 - rowMod;
644 		arm = armQ + 1 + logArm;
645 		if (arm >= SPAN_ROW_SIZE(map, ld, span))
646 			arm -= SPAN_ROW_SIZE(map, ld, span);
647 		physArm = (u8)arm;
648 	} else
649 		/* Calculate the arm */
650 		physArm = get_arm(instance, ld, span, stripRow, map);
651 	if (physArm == 0xFF)
652 		return FALSE;
653 
654 	arRef       = MR_LdSpanArrayGet(ld, span, map);
655 	pd          = MR_ArPdGet(arRef, physArm, map);
656 
657 	if (pd != MR_PD_INVALID)
658 		*pDevHandle = MR_PdDevHandleGet(pd, map);
659 	else {
660 		*pDevHandle = MR_PD_INVALID;
661 		if ((raid->level >= 5) &&
662 			(!do_invader  || (do_invader &&
663 			(raid->regTypeReqOnRead != REGION_TYPE_UNUSED))))
664 			pRAID_Context->regLockFlags = REGION_TYPE_EXCLUSIVE;
665 		else if (raid->level == 1) {
666 			pd = MR_ArPdGet(arRef, physArm + 1, map);
667 			if (pd != MR_PD_INVALID)
668 				*pDevHandle = MR_PdDevHandleGet(pd, map);
669 		}
670 	}
671 
672 	*pdBlock += stripRef + MR_LdSpanPtrGet(ld, span, map)->startBlk;
673 	pRAID_Context->spanArm = (span << RAID_CTX_SPANARM_SPAN_SHIFT) |
674 					physArm;
675 	return retval;
676 }
677 
678 /*
679 ******************************************************************************
680 *
681 * This routine calculates the arm, span and block for the specified stripe and
682 * reference in stripe.
683 *
684 * Inputs :
685 *
686 *    ld   - Logical drive number
687 *    stripRow        - Stripe number
688 *    stripRef    - Reference in stripe
689 *
690 * Outputs :
691 *
692 *    span          - Span number
693 *    block         - Absolute Block number in the physical disk
694 */
695 u8 MR_GetPhyParams(struct megasas_instance *instance, u32 ld, u64 stripRow,
696 		u16 stripRef, struct IO_REQUEST_INFO *io_info,
697 		struct RAID_CONTEXT *pRAID_Context,
698 		struct MR_FW_RAID_MAP_ALL *map)
699 {
700 	struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
701 	u32         pd, arRef;
702 	u8          physArm, span;
703 	u64         row;
704 	u8	    retval = TRUE;
705 	u8          do_invader = 0;
706 	u64	    *pdBlock = &io_info->pdBlock;
707 	u16	    *pDevHandle = &io_info->devHandle;
708 
709 	if ((instance->pdev->device == PCI_DEVICE_ID_LSI_INVADER ||
710 		instance->pdev->device == PCI_DEVICE_ID_LSI_FURY))
711 		do_invader = 1;
712 
713 	row =  mega_div64_32(stripRow, raid->rowDataSize);
714 
715 	if (raid->level == 6) {
716 		/* logical arm within row */
717 		u32 logArm =  mega_mod64(stripRow, raid->rowDataSize);
718 		u32 rowMod, armQ, arm;
719 
720 		if (raid->rowSize == 0)
721 			return FALSE;
722 		/* get logical row mod */
723 		rowMod = mega_mod64(row, raid->rowSize);
724 		armQ = raid->rowSize-1-rowMod; /* index of Q drive */
725 		arm = armQ+1+logArm; /* data always logically follows Q */
726 		if (arm >= raid->rowSize) /* handle wrap condition */
727 			arm -= raid->rowSize;
728 		physArm = (u8)arm;
729 	} else  {
730 		if (raid->modFactor == 0)
731 			return FALSE;
732 		physArm = MR_LdDataArmGet(ld,  mega_mod64(stripRow,
733 							  raid->modFactor),
734 					  map);
735 	}
736 
737 	if (raid->spanDepth == 1) {
738 		span = 0;
739 		*pdBlock = row << raid->stripeShift;
740 	} else {
741 		span = (u8)MR_GetSpanBlock(ld, row, pdBlock, map);
742 		if (span == SPAN_INVALID)
743 			return FALSE;
744 	}
745 
746 	/* Get the array on which this span is present */
747 	arRef       = MR_LdSpanArrayGet(ld, span, map);
748 	pd          = MR_ArPdGet(arRef, physArm, map); /* Get the pd */
749 
750 	if (pd != MR_PD_INVALID)
751 		/* Get dev handle from Pd. */
752 		*pDevHandle = MR_PdDevHandleGet(pd, map);
753 	else {
754 		*pDevHandle = MR_PD_INVALID; /* set dev handle as invalid. */
755 		if ((raid->level >= 5) &&
756 			(!do_invader  || (do_invader &&
757 			(raid->regTypeReqOnRead != REGION_TYPE_UNUSED))))
758 			pRAID_Context->regLockFlags = REGION_TYPE_EXCLUSIVE;
759 		else if (raid->level == 1) {
760 			/* Get alternate Pd. */
761 			pd = MR_ArPdGet(arRef, physArm + 1, map);
762 			if (pd != MR_PD_INVALID)
763 				/* Get dev handle from Pd */
764 				*pDevHandle = MR_PdDevHandleGet(pd, map);
765 		}
766 	}
767 
768 	*pdBlock += stripRef + MR_LdSpanPtrGet(ld, span, map)->startBlk;
769 	pRAID_Context->spanArm = (span << RAID_CTX_SPANARM_SPAN_SHIFT) |
770 		physArm;
771 	return retval;
772 }
773 
774 /*
775 ******************************************************************************
776 *
777 * MR_BuildRaidContext function
778 *
779 * This function will initiate command processing.  The start/end row and strip
780 * information is calculated then the lock is acquired.
781 * This function will return 0 if region lock was acquired OR return num strips
782 */
783 u8
784 MR_BuildRaidContext(struct megasas_instance *instance,
785 		    struct IO_REQUEST_INFO *io_info,
786 		    struct RAID_CONTEXT *pRAID_Context,
787 		    struct MR_FW_RAID_MAP_ALL *map)
788 {
789 	struct MR_LD_RAID  *raid;
790 	u32         ld, stripSize, stripe_mask;
791 	u64         endLba, endStrip, endRow, start_row, start_strip;
792 	u64         regStart;
793 	u32         regSize;
794 	u8          num_strips, numRows;
795 	u16         ref_in_start_stripe, ref_in_end_stripe;
796 	u64         ldStartBlock;
797 	u32         numBlocks, ldTgtId;
798 	u8          isRead;
799 	u8	    retval = 0;
800 	u8	    startlba_span = SPAN_INVALID;
801 	u64 *pdBlock = &io_info->pdBlock;
802 
803 	ldStartBlock = io_info->ldStartBlock;
804 	numBlocks = io_info->numBlocks;
805 	ldTgtId = io_info->ldTgtId;
806 	isRead = io_info->isRead;
807 	io_info->IoforUnevenSpan = 0;
808 	io_info->start_span	= SPAN_INVALID;
809 
810 	ld = MR_TargetIdToLdGet(ldTgtId, map);
811 	raid = MR_LdRaidGet(ld, map);
812 
813 	/*
814 	 * if rowDataSize @RAID map and spanRowDataSize @SPAN INFO are zero
815 	 * return FALSE
816 	 */
817 	if (raid->rowDataSize == 0) {
818 		if (MR_LdSpanPtrGet(ld, 0, map)->spanRowDataSize == 0)
819 			return FALSE;
820 		else if (instance->UnevenSpanSupport) {
821 			io_info->IoforUnevenSpan = 1;
822 		} else {
823 			dev_info(&instance->pdev->dev,
824 				"raid->rowDataSize is 0, but has SPAN[0]"
825 				"rowDataSize = 0x%0x,"
826 				"but there is _NO_ UnevenSpanSupport\n",
827 				MR_LdSpanPtrGet(ld, 0, map)->spanRowDataSize);
828 			return FALSE;
829 		}
830 	}
831 
832 	stripSize = 1 << raid->stripeShift;
833 	stripe_mask = stripSize-1;
834 
835 
836 	/*
837 	 * calculate starting row and stripe, and number of strips and rows
838 	 */
839 	start_strip         = ldStartBlock >> raid->stripeShift;
840 	ref_in_start_stripe = (u16)(ldStartBlock & stripe_mask);
841 	endLba              = ldStartBlock + numBlocks - 1;
842 	ref_in_end_stripe   = (u16)(endLba & stripe_mask);
843 	endStrip            = endLba >> raid->stripeShift;
844 	num_strips          = (u8)(endStrip - start_strip + 1); /* End strip */
845 
846 	if (io_info->IoforUnevenSpan) {
847 		start_row = get_row_from_strip(instance, ld, start_strip, map);
848 		endRow	  = get_row_from_strip(instance, ld, endStrip, map);
849 		if (start_row == -1ULL || endRow == -1ULL) {
850 			dev_info(&instance->pdev->dev, "return from %s %d."
851 				"Send IO w/o region lock.\n",
852 				__func__, __LINE__);
853 			return FALSE;
854 		}
855 
856 		if (raid->spanDepth == 1) {
857 			startlba_span = 0;
858 			*pdBlock = start_row << raid->stripeShift;
859 		} else
860 			startlba_span = (u8)mr_spanset_get_span_block(instance,
861 						ld, start_row, pdBlock, map);
862 		if (startlba_span == SPAN_INVALID) {
863 			dev_info(&instance->pdev->dev, "return from %s %d"
864 				"for row 0x%llx,start strip %llx"
865 				"endSrip %llx\n", __func__, __LINE__,
866 				(unsigned long long)start_row,
867 				(unsigned long long)start_strip,
868 				(unsigned long long)endStrip);
869 			return FALSE;
870 		}
871 		io_info->start_span	= startlba_span;
872 		io_info->start_row	= start_row;
873 #if SPAN_DEBUG
874 		dev_dbg(&instance->pdev->dev, "Check Span number from %s %d"
875 			"for row 0x%llx, start strip 0x%llx end strip 0x%llx"
876 			" span 0x%x\n", __func__, __LINE__,
877 			(unsigned long long)start_row,
878 			(unsigned long long)start_strip,
879 			(unsigned long long)endStrip, startlba_span);
880 		dev_dbg(&instance->pdev->dev, "start_row 0x%llx endRow 0x%llx"
881 			"Start span 0x%x\n", (unsigned long long)start_row,
882 			(unsigned long long)endRow, startlba_span);
883 #endif
884 	} else {
885 		start_row = mega_div64_32(start_strip, raid->rowDataSize);
886 		endRow    = mega_div64_32(endStrip, raid->rowDataSize);
887 	}
888 	numRows = (u8)(endRow - start_row + 1);
889 
890 	/*
891 	 * calculate region info.
892 	 */
893 
894 	/* assume region is at the start of the first row */
895 	regStart            = start_row << raid->stripeShift;
896 	/* assume this IO needs the full row - we'll adjust if not true */
897 	regSize             = stripSize;
898 
899 	/* Check if we can send this I/O via FastPath */
900 	if (raid->capability.fpCapable) {
901 		if (isRead)
902 			io_info->fpOkForIo = (raid->capability.fpReadCapable &&
903 					      ((num_strips == 1) ||
904 					       raid->capability.
905 					       fpReadAcrossStripe));
906 		else
907 			io_info->fpOkForIo = (raid->capability.fpWriteCapable &&
908 					      ((num_strips == 1) ||
909 					       raid->capability.
910 					       fpWriteAcrossStripe));
911 	} else
912 		io_info->fpOkForIo = FALSE;
913 
914 	if (numRows == 1) {
915 		/* single-strip IOs can always lock only the data needed */
916 		if (num_strips == 1) {
917 			regStart += ref_in_start_stripe;
918 			regSize = numBlocks;
919 		}
920 		/* multi-strip IOs always need to full stripe locked */
921 	} else if (io_info->IoforUnevenSpan == 0) {
922 		/*
923 		 * For Even span region lock optimization.
924 		 * If the start strip is the last in the start row
925 		 */
926 		if (start_strip == (start_row + 1) * raid->rowDataSize - 1) {
927 			regStart += ref_in_start_stripe;
928 			/* initialize count to sectors from startref to end
929 			   of strip */
930 			regSize = stripSize - ref_in_start_stripe;
931 		}
932 
933 		/* add complete rows in the middle of the transfer */
934 		if (numRows > 2)
935 			regSize += (numRows-2) << raid->stripeShift;
936 
937 		/* if IO ends within first strip of last row*/
938 		if (endStrip == endRow*raid->rowDataSize)
939 			regSize += ref_in_end_stripe+1;
940 		else
941 			regSize += stripSize;
942 	} else {
943 		/*
944 		 * For Uneven span region lock optimization.
945 		 * If the start strip is the last in the start row
946 		 */
947 		if (start_strip == (get_strip_from_row(instance, ld, start_row, map) +
948 				SPAN_ROW_DATA_SIZE(map, ld, startlba_span) - 1)) {
949 			regStart += ref_in_start_stripe;
950 			/* initialize count to sectors from
951 			 * startRef to end of strip
952 			 */
953 			regSize = stripSize - ref_in_start_stripe;
954 		}
955 		/* Add complete rows in the middle of the transfer*/
956 
957 		if (numRows > 2)
958 			/* Add complete rows in the middle of the transfer*/
959 			regSize += (numRows-2) << raid->stripeShift;
960 
961 		/* if IO ends within first strip of last row */
962 		if (endStrip == get_strip_from_row(instance, ld, endRow, map))
963 			regSize += ref_in_end_stripe + 1;
964 		else
965 			regSize += stripSize;
966 	}
967 
968 	pRAID_Context->timeoutValue     = map->raidMap.fpPdIoTimeoutSec;
969 	if ((instance->pdev->device == PCI_DEVICE_ID_LSI_INVADER) ||
970 		(instance->pdev->device == PCI_DEVICE_ID_LSI_FURY))
971 		pRAID_Context->regLockFlags = (isRead) ?
972 			raid->regTypeReqOnRead : raid->regTypeReqOnWrite;
973 	else
974 		pRAID_Context->regLockFlags = (isRead) ?
975 			REGION_TYPE_SHARED_READ : raid->regTypeReqOnWrite;
976 	pRAID_Context->VirtualDiskTgtId = raid->targetId;
977 	pRAID_Context->regLockRowLBA    = regStart;
978 	pRAID_Context->regLockLength    = regSize;
979 	pRAID_Context->configSeqNum	= raid->seqNum;
980 
981 	/*Get Phy Params only if FP capable, or else leave it to MR firmware
982 	  to do the calculation.*/
983 	if (io_info->fpOkForIo) {
984 		retval = io_info->IoforUnevenSpan ?
985 				mr_spanset_get_phy_params(instance, ld,
986 					start_strip, ref_in_start_stripe,
987 					io_info, pRAID_Context, map) :
988 				MR_GetPhyParams(instance, ld, start_strip,
989 					ref_in_start_stripe, io_info,
990 					pRAID_Context, map);
991 		/* If IO on an invalid Pd, then FP is not possible.*/
992 		if (io_info->devHandle == MR_PD_INVALID)
993 			io_info->fpOkForIo = FALSE;
994 		return retval;
995 	} else if (isRead) {
996 		uint stripIdx;
997 		for (stripIdx = 0; stripIdx < num_strips; stripIdx++) {
998 			retval = io_info->IoforUnevenSpan ?
999 				mr_spanset_get_phy_params(instance, ld,
1000 				    start_strip + stripIdx,
1001 				    ref_in_start_stripe, io_info,
1002 				    pRAID_Context, map) :
1003 				MR_GetPhyParams(instance, ld,
1004 				    start_strip + stripIdx, ref_in_start_stripe,
1005 				    io_info, pRAID_Context, map);
1006 			if (!retval)
1007 				return TRUE;
1008 		}
1009 	}
1010 
1011 #if SPAN_DEBUG
1012 	/* Just for testing what arm we get for strip.*/
1013 	if (io_info->IoforUnevenSpan)
1014 		get_arm_from_strip(instance, ld, start_strip, map);
1015 #endif
1016 	return TRUE;
1017 }
1018 
1019 /*
1020 ******************************************************************************
1021 *
1022 * This routine pepare spanset info from Valid Raid map and store it into
1023 * local copy of ldSpanInfo per instance data structure.
1024 *
1025 * Inputs :
1026 * map    - LD map
1027 * ldSpanInfo - ldSpanInfo per HBA instance
1028 *
1029 */
1030 void mr_update_span_set(struct MR_FW_RAID_MAP_ALL *map,
1031 			PLD_SPAN_INFO ldSpanInfo)
1032 {
1033 	u8   span, count;
1034 	u32  element, span_row_width;
1035 	u64  span_row;
1036 	struct MR_LD_RAID *raid;
1037 	LD_SPAN_SET *span_set, *span_set_prev;
1038 	struct MR_QUAD_ELEMENT    *quad;
1039 	int ldCount;
1040 	u16 ld;
1041 
1042 
1043 	for (ldCount = 0; ldCount < MAX_LOGICAL_DRIVES; ldCount++) {
1044 		ld = MR_TargetIdToLdGet(ldCount, map);
1045 		if (ld >= MAX_LOGICAL_DRIVES)
1046 			continue;
1047 		raid = MR_LdRaidGet(ld, map);
1048 		for (element = 0; element < MAX_QUAD_DEPTH; element++) {
1049 			for (span = 0; span < raid->spanDepth; span++) {
1050 				if (map->raidMap.ldSpanMap[ld].spanBlock[span].
1051 					block_span_info.noElements <
1052 					element + 1)
1053 					continue;
1054 				span_set = &(ldSpanInfo[ld].span_set[element]);
1055 				quad = &map->raidMap.ldSpanMap[ld].
1056 					spanBlock[span].block_span_info.
1057 					quad[element];
1058 
1059 				span_set->diff = quad->diff;
1060 
1061 				for (count = 0, span_row_width = 0;
1062 					count < raid->spanDepth; count++) {
1063 					if (map->raidMap.ldSpanMap[ld].
1064 						spanBlock[count].
1065 						block_span_info.
1066 						noElements >= element + 1) {
1067 						span_set->strip_offset[count] =
1068 							span_row_width;
1069 						span_row_width +=
1070 							MR_LdSpanPtrGet
1071 							(ld, count, map)->spanRowDataSize;
1072 						printk(KERN_INFO "megasas:"
1073 							"span %x rowDataSize %x\n",
1074 							count, MR_LdSpanPtrGet
1075 							(ld, count, map)->spanRowDataSize);
1076 					}
1077 				}
1078 
1079 				span_set->span_row_data_width = span_row_width;
1080 				span_row = mega_div64_32(((quad->logEnd -
1081 					quad->logStart) + quad->diff),
1082 					quad->diff);
1083 
1084 				if (element == 0) {
1085 					span_set->log_start_lba = 0;
1086 					span_set->log_end_lba =
1087 						((span_row << raid->stripeShift)
1088 						* span_row_width) - 1;
1089 
1090 					span_set->span_row_start = 0;
1091 					span_set->span_row_end = span_row - 1;
1092 
1093 					span_set->data_strip_start = 0;
1094 					span_set->data_strip_end =
1095 						(span_row * span_row_width) - 1;
1096 
1097 					span_set->data_row_start = 0;
1098 					span_set->data_row_end =
1099 						(span_row * quad->diff) - 1;
1100 				} else {
1101 					span_set_prev = &(ldSpanInfo[ld].
1102 							span_set[element - 1]);
1103 					span_set->log_start_lba =
1104 						span_set_prev->log_end_lba + 1;
1105 					span_set->log_end_lba =
1106 						span_set->log_start_lba +
1107 						((span_row << raid->stripeShift)
1108 						* span_row_width) - 1;
1109 
1110 					span_set->span_row_start =
1111 						span_set_prev->span_row_end + 1;
1112 					span_set->span_row_end =
1113 					span_set->span_row_start + span_row - 1;
1114 
1115 					span_set->data_strip_start =
1116 					span_set_prev->data_strip_end + 1;
1117 					span_set->data_strip_end =
1118 						span_set->data_strip_start +
1119 						(span_row * span_row_width) - 1;
1120 
1121 					span_set->data_row_start =
1122 						span_set_prev->data_row_end + 1;
1123 					span_set->data_row_end =
1124 						span_set->data_row_start +
1125 						(span_row * quad->diff) - 1;
1126 				}
1127 				break;
1128 		}
1129 		if (span == raid->spanDepth)
1130 			break;
1131 	    }
1132 	}
1133 #if SPAN_DEBUG
1134 	getSpanInfo(map, ldSpanInfo);
1135 #endif
1136 
1137 }
1138 
1139 void
1140 mr_update_load_balance_params(struct MR_FW_RAID_MAP_ALL *map,
1141 			      struct LD_LOAD_BALANCE_INFO *lbInfo)
1142 {
1143 	int ldCount;
1144 	u16 ld;
1145 	struct MR_LD_RAID *raid;
1146 
1147 	for (ldCount = 0; ldCount < MAX_LOGICAL_DRIVES; ldCount++) {
1148 		ld = MR_TargetIdToLdGet(ldCount, map);
1149 		if (ld >= MAX_LOGICAL_DRIVES) {
1150 			lbInfo[ldCount].loadBalanceFlag = 0;
1151 			continue;
1152 		}
1153 
1154 		raid = MR_LdRaidGet(ld, map);
1155 
1156 		/* Two drive Optimal RAID 1 */
1157 		if ((raid->level == 1)  &&  (raid->rowSize == 2) &&
1158 		    (raid->spanDepth == 1) && raid->ldState ==
1159 		    MR_LD_STATE_OPTIMAL) {
1160 			u32 pd, arRef;
1161 
1162 			lbInfo[ldCount].loadBalanceFlag = 1;
1163 
1164 			/* Get the array on which this span is present */
1165 			arRef = MR_LdSpanArrayGet(ld, 0, map);
1166 
1167 			/* Get the Pd */
1168 			pd = MR_ArPdGet(arRef, 0, map);
1169 			/* Get dev handle from Pd */
1170 			lbInfo[ldCount].raid1DevHandle[0] =
1171 				MR_PdDevHandleGet(pd, map);
1172 			/* Get the Pd */
1173 			pd = MR_ArPdGet(arRef, 1, map);
1174 
1175 			/* Get the dev handle from Pd */
1176 			lbInfo[ldCount].raid1DevHandle[1] =
1177 				MR_PdDevHandleGet(pd, map);
1178 		} else
1179 			lbInfo[ldCount].loadBalanceFlag = 0;
1180 	}
1181 }
1182 
1183 u8 megasas_get_best_arm(struct LD_LOAD_BALANCE_INFO *lbInfo, u8 arm, u64 block,
1184 			u32 count)
1185 {
1186 	u16     pend0, pend1;
1187 	u64     diff0, diff1;
1188 	u8      bestArm;
1189 
1190 	/* get the pending cmds for the data and mirror arms */
1191 	pend0 = atomic_read(&lbInfo->scsi_pending_cmds[0]);
1192 	pend1 = atomic_read(&lbInfo->scsi_pending_cmds[1]);
1193 
1194 	/* Determine the disk whose head is nearer to the req. block */
1195 	diff0 = ABS_DIFF(block, lbInfo->last_accessed_block[0]);
1196 	diff1 = ABS_DIFF(block, lbInfo->last_accessed_block[1]);
1197 	bestArm = (diff0 <= diff1 ? 0 : 1);
1198 
1199 	/*Make balance count from 16 to 4 to keep driver in sync with Firmware*/
1200 	if ((bestArm == arm && pend0 > pend1 + 4)  ||
1201 	    (bestArm != arm && pend1 > pend0 + 4))
1202 		bestArm ^= 1;
1203 
1204 	/* Update the last accessed block on the correct pd */
1205 	lbInfo->last_accessed_block[bestArm] = block + count - 1;
1206 
1207 	return bestArm;
1208 }
1209 
1210 u16 get_updated_dev_handle(struct LD_LOAD_BALANCE_INFO *lbInfo,
1211 			   struct IO_REQUEST_INFO *io_info)
1212 {
1213 	u8 arm, old_arm;
1214 	u16 devHandle;
1215 
1216 	old_arm = lbInfo->raid1DevHandle[0] == io_info->devHandle ? 0 : 1;
1217 
1218 	/* get best new arm */
1219 	arm  = megasas_get_best_arm(lbInfo, old_arm, io_info->ldStartBlock,
1220 				    io_info->numBlocks);
1221 	devHandle = lbInfo->raid1DevHandle[arm];
1222 	atomic_inc(&lbInfo->scsi_pending_cmds[arm]);
1223 
1224 	return devHandle;
1225 }
1226