1/*	$NetBSD: rf_dagfuncs.c,v 1.35 2021/08/07 16:19:15 thorpej Exp $	*/
2/*
3 * Copyright (c) 1995 Carnegie-Mellon University.
4 * All rights reserved.
5 *
6 * Author: Mark Holland, William V. Courtright II
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 * dagfuncs.c -- DAG node execution routines
31 *
32 * Rules:
33 * 1. Every DAG execution function must eventually cause node->status to
34 *    get set to "good" or "bad", and "FinishNode" to be called. In the
35 *    case of nodes that complete immediately (xor, NullNodeFunc, etc),
36 *    the node execution function can do these two things directly. In
37 *    the case of nodes that have to wait for some event (a disk read to
38 *    complete, a lock to be released, etc) to occur before they can
39 *    complete, this is typically achieved by having whatever module
40 *    is doing the operation call GenericWakeupFunc upon completion.
41 * 2. DAG execution functions should check the status in the DAG header
42 *    and NOP out their operations if the status is not "enable". However,
43 *    execution functions that release resources must be sure to release
44 *    them even when they NOP out the function that would use them.
45 *    Functions that acquire resources should go ahead and acquire them
46 *    even when they NOP, so that a downstream release node will not have
47 *    to check to find out whether or not the acquire was suppressed.
48 */
49
50#include <sys/cdefs.h>
51__KERNEL_RCSID(0, "$NetBSD: rf_dagfuncs.c,v 1.35 2021/08/07 16:19:15 thorpej Exp $");
52
53#include <sys/param.h>
54#include <sys/ioctl.h>
55
56#include "rf_archs.h"
57#include "rf_raid.h"
58#include "rf_dag.h"
59#include "rf_layout.h"
60#include "rf_etimer.h"
61#include "rf_acctrace.h"
62#include "rf_diskqueue.h"
63#include "rf_dagfuncs.h"
64#include "rf_general.h"
65#include "rf_engine.h"
66#include "rf_dagutils.h"
67
68#include "rf_kintf.h"
69
70#if RF_INCLUDE_PARITYLOGGING > 0
71#include "rf_paritylog.h"
72#endif				/* RF_INCLUDE_PARITYLOGGING > 0 */
73
74void     (*rf_DiskReadFunc) (RF_DagNode_t *);
75void     (*rf_DiskWriteFunc) (RF_DagNode_t *);
76void     (*rf_DiskReadUndoFunc) (RF_DagNode_t *);
77void     (*rf_DiskWriteUndoFunc) (RF_DagNode_t *);
78void     (*rf_RegularXorUndoFunc) (RF_DagNode_t *);
79void     (*rf_SimpleXorUndoFunc) (RF_DagNode_t *);
80void     (*rf_RecoveryXorUndoFunc) (RF_DagNode_t *);
81
82/*****************************************************************************
83 * main (only) configuration routine for this module
84 ****************************************************************************/
85int
86rf_ConfigureDAGFuncs(RF_ShutdownList_t **listp)
87{
88	RF_ASSERT(((sizeof(long) == 8) && RF_LONGSHIFT == 3) ||
89		  ((sizeof(long) == 4) && RF_LONGSHIFT == 2));
90	rf_DiskReadFunc = rf_DiskReadFuncForThreads;
91	rf_DiskReadUndoFunc = rf_DiskUndoFunc;
92	rf_DiskWriteFunc = rf_DiskWriteFuncForThreads;
93	rf_DiskWriteUndoFunc = rf_DiskUndoFunc;
94	rf_RegularXorUndoFunc = rf_NullNodeUndoFunc;
95	rf_SimpleXorUndoFunc = rf_NullNodeUndoFunc;
96	rf_RecoveryXorUndoFunc = rf_NullNodeUndoFunc;
97	return (0);
98}
99
100
101
102/*****************************************************************************
103 * the execution function associated with a terminate node
104 ****************************************************************************/
105void
106rf_TerminateFunc(RF_DagNode_t *node)
107{
108	RF_ASSERT(node->dagHdr->numCommits == node->dagHdr->numCommitNodes);
109	node->status = rf_good;
110	rf_FinishNode(node, RF_THREAD_CONTEXT);
111}
112
113void
114rf_TerminateUndoFunc(RF_DagNode_t *node)
115{
116}
117
118
119/*****************************************************************************
120 * execution functions associated with a mirror node
121 *
122 * parameters:
123 *
124 * 0 - physical disk address of data
125 * 1 - buffer for holding read data
126 * 2 - parity stripe ID
127 * 3 - flags
128 * 4 - physical disk address of mirror (parity)
129 *
130 ****************************************************************************/
131
132void
133rf_DiskReadMirrorIdleFunc(RF_DagNode_t *node)
134{
135	/* select the mirror copy with the shortest queue and fill in node
136	 * parameters with physical disk address */
137
138	rf_SelectMirrorDiskIdle(node);
139	rf_DiskReadFunc(node);
140}
141
142#if (RF_INCLUDE_CHAINDECLUSTER > 0) || (RF_INCLUDE_INTERDECLUSTER > 0) || (RF_DEBUG_VALIDATE_DAG > 0)
143void
144rf_DiskReadMirrorPartitionFunc(RF_DagNode_t *node)
145{
146	/* select the mirror copy with the shortest queue and fill in node
147	 * parameters with physical disk address */
148
149	rf_SelectMirrorDiskPartition(node);
150	rf_DiskReadFunc(node);
151}
152#endif
153
154void
155rf_DiskReadMirrorUndoFunc(RF_DagNode_t *node)
156{
157}
158
159
160
161#if RF_INCLUDE_PARITYLOGGING > 0
162/*****************************************************************************
163 * the execution function associated with a parity log update node
164 ****************************************************************************/
165void
166rf_ParityLogUpdateFunc(RF_DagNode_t *node)
167{
168	RF_PhysDiskAddr_t *pda = (RF_PhysDiskAddr_t *) node->params[0].p;
169	void *bf = (void *) node->params[1].p;
170	RF_ParityLogData_t *logData;
171#if RF_ACC_TRACE > 0
172	RF_AccTraceEntry_t *tracerec = node->dagHdr->tracerec;
173	RF_Etimer_t timer;
174#endif
175
176	if (node->dagHdr->status == rf_enable) {
177#if RF_ACC_TRACE > 0
178		RF_ETIMER_START(timer);
179#endif
180		logData = rf_CreateParityLogData(RF_UPDATE, pda, bf,
181		    (RF_Raid_t *) (node->dagHdr->raidPtr),
182		    node->wakeFunc, node,
183		    node->dagHdr->tracerec, timer);
184		if (logData)
185			rf_ParityLogAppend(logData, RF_FALSE, NULL, RF_FALSE);
186		else {
187#if RF_ACC_TRACE > 0
188			RF_ETIMER_STOP(timer);
189			RF_ETIMER_EVAL(timer);
190			tracerec->plog_us += RF_ETIMER_VAL_US(timer);
191#endif
192			(node->wakeFunc) (node, ENOMEM);
193		}
194	}
195}
196
197
198/*****************************************************************************
199 * the execution function associated with a parity log overwrite node
200 ****************************************************************************/
201void
202rf_ParityLogOverwriteFunc(RF_DagNode_t *node)
203{
204	RF_PhysDiskAddr_t *pda = (RF_PhysDiskAddr_t *) node->params[0].p;
205	void *bf = (void *) node->params[1].p;
206	RF_ParityLogData_t *logData;
207#if RF_ACC_TRACE > 0
208	RF_AccTraceEntry_t *tracerec = node->dagHdr->tracerec;
209	RF_Etimer_t timer;
210#endif
211
212	if (node->dagHdr->status == rf_enable) {
213#if RF_ACC_TRACE > 0
214		RF_ETIMER_START(timer);
215#endif
216		logData = rf_CreateParityLogData(RF_OVERWRITE, pda, bf,
217(RF_Raid_t *) (node->dagHdr->raidPtr),
218		    node->wakeFunc, node, node->dagHdr->tracerec, timer);
219		if (logData)
220			rf_ParityLogAppend(logData, RF_FALSE, NULL, RF_FALSE);
221		else {
222#if RF_ACC_TRACE > 0
223			RF_ETIMER_STOP(timer);
224			RF_ETIMER_EVAL(timer);
225			tracerec->plog_us += RF_ETIMER_VAL_US(timer);
226#endif
227			(node->wakeFunc) (node, ENOMEM);
228		}
229	}
230}
231
232void
233rf_ParityLogUpdateUndoFunc(RF_DagNode_t *node)
234{
235}
236
237void
238rf_ParityLogOverwriteUndoFunc(RF_DagNode_t *node)
239{
240}
241#endif				/* RF_INCLUDE_PARITYLOGGING > 0 */
242
243/*****************************************************************************
244 * the execution function associated with a NOP node
245 ****************************************************************************/
246void
247rf_NullNodeFunc(RF_DagNode_t *node)
248{
249	node->status = rf_good;
250	rf_FinishNode(node, RF_THREAD_CONTEXT);
251}
252
253void
254rf_NullNodeUndoFunc(RF_DagNode_t *node)
255{
256	node->status = rf_undone;
257	rf_FinishNode(node, RF_THREAD_CONTEXT);
258}
259
260
261/*****************************************************************************
262 * the execution function associated with a disk-read node
263 ****************************************************************************/
264void
265rf_DiskReadFuncForThreads(RF_DagNode_t *node)
266{
267	RF_DiskQueueData_t *req;
268	RF_PhysDiskAddr_t *pda = (RF_PhysDiskAddr_t *) node->params[0].p;
269	void *bf = (void *) node->params[1].p;
270	RF_StripeNum_t parityStripeID = (RF_StripeNum_t) node->params[2].v;
271	unsigned priority = RF_EXTRACT_PRIORITY(node->params[3].v);
272	unsigned which_ru = RF_EXTRACT_RU(node->params[3].v);
273	RF_IoType_t iotype = (node->dagHdr->status == rf_enable) ? RF_IO_TYPE_READ : RF_IO_TYPE_NOP;
274	RF_DiskQueue_t *dqs = ((RF_Raid_t *) (node->dagHdr->raidPtr))->Queues;
275
276	req = rf_CreateDiskQueueData(iotype, pda->startSector, pda->numSector,
277	    bf, parityStripeID, which_ru, node->wakeFunc, node,
278#if RF_ACC_TRACE > 0
279	     node->dagHdr->tracerec,
280#else
281             NULL,
282#endif
283	    (void *) (node->dagHdr->raidPtr), 0, node->dagHdr->bp);
284
285	node->dagFuncData = (void *) req;
286	rf_DiskIOEnqueue(&(dqs[pda->col]), req, priority);
287}
288
289
290/*****************************************************************************
291 * the execution function associated with a disk-write node
292 ****************************************************************************/
293void
294rf_DiskWriteFuncForThreads(RF_DagNode_t *node)
295{
296	RF_DiskQueueData_t *req;
297	RF_PhysDiskAddr_t *pda = (RF_PhysDiskAddr_t *) node->params[0].p;
298	void *bf = (void *) node->params[1].p;
299	RF_StripeNum_t parityStripeID = (RF_StripeNum_t) node->params[2].v;
300	unsigned priority = RF_EXTRACT_PRIORITY(node->params[3].v);
301	unsigned which_ru = RF_EXTRACT_RU(node->params[3].v);
302	RF_IoType_t iotype = (node->dagHdr->status == rf_enable) ? RF_IO_TYPE_WRITE : RF_IO_TYPE_NOP;
303	RF_DiskQueue_t *dqs = ((RF_Raid_t *) (node->dagHdr->raidPtr))->Queues;
304
305	/* normal processing (rollaway or forward recovery) begins here */
306	req = rf_CreateDiskQueueData(iotype, pda->startSector, pda->numSector,
307	    bf, parityStripeID, which_ru, node->wakeFunc, node,
308#if RF_ACC_TRACE > 0
309	    node->dagHdr->tracerec,
310#else
311	    NULL,
312#endif
313	    (void *) (node->dagHdr->raidPtr),
314	    0, node->dagHdr->bp);
315
316	node->dagFuncData = (void *) req;
317	rf_DiskIOEnqueue(&(dqs[pda->col]), req, priority);
318}
319/*****************************************************************************
320 * the undo function for disk nodes
321 * Note:  this is not a proper undo of a write node, only locks are released.
322 *        old data is not restored to disk!
323 ****************************************************************************/
324void
325rf_DiskUndoFunc(RF_DagNode_t *node)
326{
327	RF_DiskQueueData_t *req;
328	RF_PhysDiskAddr_t *pda = (RF_PhysDiskAddr_t *) node->params[0].p;
329	RF_DiskQueue_t *dqs = ((RF_Raid_t *) (node->dagHdr->raidPtr))->Queues;
330
331	req = rf_CreateDiskQueueData(RF_IO_TYPE_NOP,
332	    0L, 0, NULL, 0L, 0, node->wakeFunc, node,
333#if RF_ACC_TRACE > 0
334	     node->dagHdr->tracerec,
335#else
336	     NULL,
337#endif
338	    (void *) (node->dagHdr->raidPtr),
339	    0, NULL);
340
341	node->dagFuncData = (void *) req;
342	rf_DiskIOEnqueue(&(dqs[pda->col]), req, RF_IO_NORMAL_PRIORITY);
343}
344
345/*****************************************************************************
346 * Callback routine for DiskRead and DiskWrite nodes.  When the disk
347 * op completes, the routine is called to set the node status and
348 * inform the execution engine that the node has fired.
349 ****************************************************************************/
350void
351rf_GenericWakeupFunc(void *v, int status)
352{
353	RF_DagNode_t *node = v;
354
355	switch (node->status) {
356	case rf_fired:
357		if (status)
358			node->status = rf_bad;
359		else
360			node->status = rf_good;
361		break;
362	case rf_recover:
363		/* probably should never reach this case */
364		if (status)
365			node->status = rf_panic;
366		else
367			node->status = rf_undone;
368		break;
369	default:
370		printf("rf_GenericWakeupFunc:");
371		printf("node->status is %d,", node->status);
372		printf("status is %d \n", status);
373		RF_PANIC();
374		break;
375	}
376	if (node->dagFuncData)
377		rf_FreeDiskQueueData((RF_DiskQueueData_t *) node->dagFuncData);
378	rf_FinishNode(node, RF_INTR_CONTEXT);
379}
380
381
382/*****************************************************************************
383 * there are three distinct types of xor nodes:
384
385 * A "regular xor" is used in the fault-free case where the access
386 * spans a complete stripe unit.  It assumes that the result buffer is
387 * one full stripe unit in size, and uses the stripe-unit-offset
388 * values that it computes from the PDAs to determine where within the
389 * stripe unit to XOR each argument buffer.
390 *
391 * A "simple xor" is used in the fault-free case where the access
392 * touches only a portion of one (or two, in some cases) stripe
393 * unit(s).  It assumes that all the argument buffers are of the same
394 * size and have the same stripe unit offset.
395 *
396 * A "recovery xor" is used in the degraded-mode case.  It's similar
397 * to the regular xor function except that it takes the failed PDA as
398 * an additional parameter, and uses it to determine what portions of
399 * the argument buffers need to be xor'd into the result buffer, and
400 * where in the result buffer they should go.
401 ****************************************************************************/
402
403/* xor the params together and store the result in the result field.
404 * assume the result field points to a buffer that is the size of one
405 * SU, and use the pda params to determine where within the buffer to
406 * XOR the input buffers.  */
407void
408rf_RegularXorFunc(RF_DagNode_t *node)
409{
410	RF_Raid_t *raidPtr = (RF_Raid_t *) node->params[node->numParams - 1].p;
411#if RF_ACC_TRACE > 0
412	RF_AccTraceEntry_t *tracerec = node->dagHdr->tracerec;
413	RF_Etimer_t timer;
414#endif
415	int     i, retcode;
416
417	retcode = 0;
418	if (node->dagHdr->status == rf_enable) {
419		/* don't do the XOR if the input is the same as the output */
420#if RF_ACC_TRACE > 0
421		RF_ETIMER_START(timer);
422#endif
423		for (i = 0; i < node->numParams - 1; i += 2)
424			if (node->params[i + 1].p != node->results[0]) {
425				retcode = rf_XorIntoBuffer(raidPtr, (RF_PhysDiskAddr_t *) node->params[i].p,
426							   (char *) node->params[i + 1].p, (char *) node->results[0]);
427			}
428#if RF_ACC_TRACE > 0
429		RF_ETIMER_STOP(timer);
430		RF_ETIMER_EVAL(timer);
431		tracerec->xor_us += RF_ETIMER_VAL_US(timer);
432#endif
433	}
434	rf_GenericWakeupFunc(node, retcode);	/* call wake func
435						 * explicitly since no
436						 * I/O in this node */
437}
438/* xor the inputs into the result buffer, ignoring placement issues */
439void
440rf_SimpleXorFunc(RF_DagNode_t *node)
441{
442	RF_Raid_t *raidPtr = (RF_Raid_t *) node->params[node->numParams - 1].p;
443	int     i, retcode = 0;
444#if RF_ACC_TRACE > 0
445	RF_AccTraceEntry_t *tracerec = node->dagHdr->tracerec;
446	RF_Etimer_t timer;
447#endif
448
449	if (node->dagHdr->status == rf_enable) {
450#if RF_ACC_TRACE > 0
451		RF_ETIMER_START(timer);
452#endif
453		/* don't do the XOR if the input is the same as the output */
454		for (i = 0; i < node->numParams - 1; i += 2)
455			if (node->params[i + 1].p != node->results[0]) {
456				retcode = rf_bxor((char *) node->params[i + 1].p, (char *) node->results[0],
457				    rf_RaidAddressToByte(raidPtr, ((RF_PhysDiskAddr_t *) node->params[i].p)->numSector));
458			}
459#if RF_ACC_TRACE > 0
460		RF_ETIMER_STOP(timer);
461		RF_ETIMER_EVAL(timer);
462		tracerec->xor_us += RF_ETIMER_VAL_US(timer);
463#endif
464	}
465	rf_GenericWakeupFunc(node, retcode);	/* call wake func
466						 * explicitly since no
467						 * I/O in this node */
468}
469/* this xor is used by the degraded-mode dag functions to recover lost
470 * data.  the second-to-last parameter is the PDA for the failed
471 * portion of the access.  the code here looks at this PDA and assumes
472 * that the xor target buffer is equal in size to the number of
473 * sectors in the failed PDA.  It then uses the other PDAs in the
474 * parameter list to determine where within the target buffer the
475 * corresponding data should be xored.  */
476void
477rf_RecoveryXorFunc(RF_DagNode_t *node)
478{
479	RF_Raid_t *raidPtr = (RF_Raid_t *) node->params[node->numParams - 1].p;
480	RF_RaidLayout_t *layoutPtr = (RF_RaidLayout_t *) & raidPtr->Layout;
481	RF_PhysDiskAddr_t *failedPDA = (RF_PhysDiskAddr_t *) node->params[node->numParams - 2].p;
482	int     i, retcode = 0;
483	RF_PhysDiskAddr_t *pda;
484	int     suoffset, failedSUOffset = rf_StripeUnitOffset(layoutPtr, failedPDA->startSector);
485	char   *srcbuf, *destbuf;
486#if RF_ACC_TRACE > 0
487	RF_AccTraceEntry_t *tracerec = node->dagHdr->tracerec;
488	RF_Etimer_t timer;
489#endif
490
491	if (node->dagHdr->status == rf_enable) {
492#if RF_ACC_TRACE > 0
493		RF_ETIMER_START(timer);
494#endif
495		for (i = 0; i < node->numParams - 2; i += 2)
496			if (node->params[i + 1].p != node->results[0]) {
497				pda = (RF_PhysDiskAddr_t *) node->params[i].p;
498				srcbuf = (char *) node->params[i + 1].p;
499				suoffset = rf_StripeUnitOffset(layoutPtr, pda->startSector);
500				destbuf = ((char *) node->results[0]) + rf_RaidAddressToByte(raidPtr, suoffset - failedSUOffset);
501				retcode = rf_bxor(srcbuf, destbuf, rf_RaidAddressToByte(raidPtr, pda->numSector));
502			}
503#if RF_ACC_TRACE > 0
504		RF_ETIMER_STOP(timer);
505		RF_ETIMER_EVAL(timer);
506		tracerec->xor_us += RF_ETIMER_VAL_US(timer);
507#endif
508	}
509	rf_GenericWakeupFunc(node, retcode);
510}
511/*****************************************************************************
512 * The next three functions are utilities used by the above
513 * xor-execution functions.
514 ****************************************************************************/
515
516
517/*
518 * this is just a glorified buffer xor.  targbuf points to a buffer
519 * that is one full stripe unit in size.  srcbuf points to a buffer
520 * that may be less than 1 SU, but never more.  When the access
521 * described by pda is one SU in size (which by implication means it's
522 * SU-aligned), all that happens is (targbuf) <- (srcbuf ^ targbuf).
523 * When the access is less than one SU in size the XOR occurs on only
524 * the portion of targbuf identified in the pda.  */
525
526int
527rf_XorIntoBuffer(RF_Raid_t *raidPtr, RF_PhysDiskAddr_t *pda,
528		 char *srcbuf, char *targbuf)
529{
530	char   *targptr;
531	int     sectPerSU = raidPtr->Layout.sectorsPerStripeUnit;
532	int     SUOffset = pda->startSector % sectPerSU;
533	int     length, retcode = 0;
534
535	RF_ASSERT(pda->numSector <= sectPerSU);
536
537	targptr = targbuf + rf_RaidAddressToByte(raidPtr, SUOffset);
538	length = rf_RaidAddressToByte(raidPtr, pda->numSector);
539	retcode = rf_bxor(srcbuf, targptr, length);
540	return (retcode);
541}
542/* it really should be the case that the buffer pointers (returned by
543 * malloc) are aligned to the natural word size of the machine, so
544 * this is the only case we optimize for.  The length should always be
545 * a multiple of the sector size, so there should be no problem with
546 * leftover bytes at the end.  */
547int
548rf_bxor(char *src, char *dest, int len)
549{
550	unsigned mask = sizeof(long) - 1, retcode = 0;
551
552	if (!(((unsigned long) src) & mask) &&
553	    !(((unsigned long) dest) & mask) && !(len & mask)) {
554		retcode = rf_longword_bxor((unsigned long *) src,
555					   (unsigned long *) dest,
556					   len >> RF_LONGSHIFT);
557	} else {
558		RF_ASSERT(0);
559	}
560	return (retcode);
561}
562
563/* When XORing in kernel mode, we need to map each user page to kernel
564 * space before we can access it.  We don't want to assume anything
565 * about which input buffers are in kernel/user space, nor about their
566 * alignment, so in each loop we compute the maximum number of bytes
567 * that we can xor without crossing any page boundaries, and do only
568 * this many bytes before the next remap.
569 *
570 * len - is in longwords
571 */
572int
573rf_longword_bxor(unsigned long *src, unsigned long *dest, int len)
574{
575	unsigned long *end = src + len;
576	unsigned long d0, d1, d2, d3, s0, s1, s2, s3;	/* temps */
577	unsigned long *pg_src, *pg_dest;   /* per-page source/dest pointers */
578	int     longs_this_time;/* # longwords to xor in the current iteration */
579
580	pg_src = src;
581	pg_dest = dest;
582	if (!pg_src || !pg_dest)
583		return (EFAULT);
584
585	while (len >= 4) {
586		longs_this_time = RF_MIN(len, RF_MIN(RF_BLIP(pg_src), RF_BLIP(pg_dest)) >> RF_LONGSHIFT);	/* note len in longwords */
587		src += longs_this_time;
588		dest += longs_this_time;
589		len -= longs_this_time;
590		while (longs_this_time >= 4) {
591			d0 = pg_dest[0];
592			d1 = pg_dest[1];
593			d2 = pg_dest[2];
594			d3 = pg_dest[3];
595			s0 = pg_src[0];
596			s1 = pg_src[1];
597			s2 = pg_src[2];
598			s3 = pg_src[3];
599			pg_dest[0] = d0 ^ s0;
600			pg_dest[1] = d1 ^ s1;
601			pg_dest[2] = d2 ^ s2;
602			pg_dest[3] = d3 ^ s3;
603			pg_src += 4;
604			pg_dest += 4;
605			longs_this_time -= 4;
606		}
607		while (longs_this_time > 0) {	/* cannot cross any page
608						 * boundaries here */
609			*pg_dest++ ^= *pg_src++;
610			longs_this_time--;
611		}
612
613		/* either we're done, or we've reached a page boundary on one
614		 * (or possibly both) of the pointers */
615		if (len) {
616			if (RF_PAGE_ALIGNED(src))
617				pg_src = src;
618			if (RF_PAGE_ALIGNED(dest))
619				pg_dest = dest;
620			if (!pg_src || !pg_dest)
621				return (EFAULT);
622		}
623	}
624	while (src < end) {
625		*pg_dest++ ^= *pg_src++;
626		src++;
627		dest++;
628		len--;
629		if (RF_PAGE_ALIGNED(src))
630			pg_src = src;
631		if (RF_PAGE_ALIGNED(dest))
632			pg_dest = dest;
633	}
634	RF_ASSERT(len == 0);
635	return (0);
636}
637
638#if 0
639/*
640   dst = a ^ b ^ c;
641   a may equal dst
642   see comment above longword_bxor
643   len is length in longwords
644*/
645int
646rf_longword_bxor3(unsigned long *dst, unsigned long *a, unsigned long *b,
647		  unsigned long *c, int len, void *bp)
648{
649	unsigned long a0, a1, a2, a3, b0, b1, b2, b3;
650	unsigned long *pg_a, *pg_b, *pg_c, *pg_dst;	/* per-page source/dest
651								 * pointers */
652	int     longs_this_time;/* # longs to xor in the current iteration */
653	char    dst_is_a = 0;
654
655	pg_a = a;
656	pg_b = b;
657	pg_c = c;
658	if (a == dst) {
659		pg_dst = pg_a;
660		dst_is_a = 1;
661	} else {
662		pg_dst = dst;
663	}
664
665	/* align dest to cache line.  Can't cross a pg boundary on dst here. */
666	while ((((unsigned long) pg_dst) & 0x1f)) {
667		*pg_dst++ = *pg_a++ ^ *pg_b++ ^ *pg_c++;
668		dst++;
669		a++;
670		b++;
671		c++;
672		if (RF_PAGE_ALIGNED(a)) {
673			pg_a = a;
674			if (!pg_a)
675				return (EFAULT);
676		}
677		if (RF_PAGE_ALIGNED(b)) {
678			pg_b = a;
679			if (!pg_b)
680				return (EFAULT);
681		}
682		if (RF_PAGE_ALIGNED(c)) {
683			pg_c = a;
684			if (!pg_c)
685				return (EFAULT);
686		}
687		len--;
688	}
689
690	while (len > 4) {
691		longs_this_time = RF_MIN(len, RF_MIN(RF_BLIP(a), RF_MIN(RF_BLIP(b), RF_MIN(RF_BLIP(c), RF_BLIP(dst)))) >> RF_LONGSHIFT);
692		a += longs_this_time;
693		b += longs_this_time;
694		c += longs_this_time;
695		dst += longs_this_time;
696		len -= longs_this_time;
697		while (longs_this_time >= 4) {
698			a0 = pg_a[0];
699			longs_this_time -= 4;
700
701			a1 = pg_a[1];
702			a2 = pg_a[2];
703
704			a3 = pg_a[3];
705			pg_a += 4;
706
707			b0 = pg_b[0];
708			b1 = pg_b[1];
709
710			b2 = pg_b[2];
711			b3 = pg_b[3];
712			/* start dual issue */
713			a0 ^= b0;
714			b0 = pg_c[0];
715
716			pg_b += 4;
717			a1 ^= b1;
718
719			a2 ^= b2;
720			a3 ^= b3;
721
722			b1 = pg_c[1];
723			a0 ^= b0;
724
725			b2 = pg_c[2];
726			a1 ^= b1;
727
728			b3 = pg_c[3];
729			a2 ^= b2;
730
731			pg_dst[0] = a0;
732			a3 ^= b3;
733			pg_dst[1] = a1;
734			pg_c += 4;
735			pg_dst[2] = a2;
736			pg_dst[3] = a3;
737			pg_dst += 4;
738		}
739		while (longs_this_time > 0) {	/* cannot cross any page
740						 * boundaries here */
741			*pg_dst++ = *pg_a++ ^ *pg_b++ ^ *pg_c++;
742			longs_this_time--;
743		}
744
745		if (len) {
746			if (RF_PAGE_ALIGNED(a)) {
747				pg_a = a;
748				if (!pg_a)
749					return (EFAULT);
750				if (dst_is_a)
751					pg_dst = pg_a;
752			}
753			if (RF_PAGE_ALIGNED(b)) {
754				pg_b = b;
755				if (!pg_b)
756					return (EFAULT);
757			}
758			if (RF_PAGE_ALIGNED(c)) {
759				pg_c = c;
760				if (!pg_c)
761					return (EFAULT);
762			}
763			if (!dst_is_a)
764				if (RF_PAGE_ALIGNED(dst)) {
765					pg_dst = dst;
766					if (!pg_dst)
767						return (EFAULT);
768				}
769		}
770	}
771	while (len) {
772		*pg_dst++ = *pg_a++ ^ *pg_b++ ^ *pg_c++;
773		dst++;
774		a++;
775		b++;
776		c++;
777		if (RF_PAGE_ALIGNED(a)) {
778			pg_a = a;
779			if (!pg_a)
780				return (EFAULT);
781			if (dst_is_a)
782				pg_dst = pg_a;
783		}
784		if (RF_PAGE_ALIGNED(b)) {
785			pg_b = b;
786			if (!pg_b)
787				return (EFAULT);
788		}
789		if (RF_PAGE_ALIGNED(c)) {
790			pg_c = c;
791			if (!pg_c)
792				return (EFAULT);
793		}
794		if (!dst_is_a)
795			if (RF_PAGE_ALIGNED(dst)) {
796				pg_dst = dst;
797				if (!pg_dst)
798					return (EFAULT);
799			}
800		len--;
801	}
802	return (0);
803}
804
805int
806rf_bxor3(unsigned char *dst, unsigned char *a, unsigned char *b,
807	 unsigned char *c, unsigned long len, void *bp)
808{
809	RF_ASSERT(((RF_UL(dst) | RF_UL(a) | RF_UL(b) | RF_UL(c) | len) & 0x7) == 0);
810
811	return (rf_longword_bxor3((unsigned long *) dst, (unsigned long *) a,
812		(unsigned long *) b, (unsigned long *) c, len >> RF_LONGSHIFT, bp));
813}
814#endif
815