summaryrefslogtreecommitdiffstats
path: root/drivers/infiniband/ulp/iser/iser_memory.c
blob: 6c5ce357fba6baa19fc62d39bd4c9b79be8c48a2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
/*
 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
 * Copyright (c) 2013-2014 Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *	- Redistributions of source code must retain the above
 *	  copyright notice, this list of conditions and the following
 *	  disclaimer.
 *
 *	- Redistributions in binary form must reproduce the above
 *	  copyright notice, this list of conditions and the following
 *	  disclaimer in the documentation and/or other materials
 *	  provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/scatterlist.h>

#include "iscsi_iser.h"

#define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */

/**
 * iser_start_rdma_unaligned_sg
 */
static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
					struct iser_data_buf *data,
					struct iser_data_buf *data_copy,
					enum iser_data_dir cmd_dir)
{
	struct ib_device *dev = iser_task->iser_conn->ib_conn.device->ib_device;
	struct scatterlist *sgl = (struct scatterlist *)data->buf;
	struct scatterlist *sg;
	char *mem = NULL;
	unsigned long  cmd_data_len = 0;
	int dma_nents, i;

	for_each_sg(sgl, sg, data->size, i)
		cmd_data_len += ib_sg_dma_len(dev, sg);

	if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
		mem = (void *)__get_free_pages(GFP_ATOMIC,
		      ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
	else
		mem = kmalloc(cmd_data_len, GFP_ATOMIC);

	if (mem == NULL) {
		iser_err("Failed to allocate mem size %d %d for copying sglist\n",
			 data->size, (int)cmd_data_len);
		return -ENOMEM;
	}

	if (cmd_dir == ISER_DIR_OUT) {
		/* copy the unaligned sg the buffer which is used for RDMA */
		int i;
		char *p, *from;

		sgl = (struct scatterlist *)data->buf;
		p = mem;
		for_each_sg(sgl, sg, data->size, i) {
			from = kmap_atomic(sg_page(sg));
			memcpy(p,
			       from + sg->offset,
			       sg->length);
			kunmap_atomic(from);
			p += sg->length;
		}
	}

	sg_init_one(&data_copy->sg_single, mem, cmd_data_len);
	data_copy->buf = &data_copy->sg_single;
	data_copy->size = 1;
	data_copy->copy_buf = mem;

	dma_nents = ib_dma_map_sg(dev, &data_copy->sg_single, 1,
				  (cmd_dir == ISER_DIR_OUT) ?
				  DMA_TO_DEVICE : DMA_FROM_DEVICE);
	BUG_ON(dma_nents == 0);

	data_copy->dma_nents = dma_nents;
	data_copy->data_len = cmd_data_len;

	return 0;
}

/**
 * iser_finalize_rdma_unaligned_sg
 */

void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
				     struct iser_data_buf *data,
				     struct iser_data_buf *data_copy,
				     enum iser_data_dir cmd_dir)
{
	struct ib_device *dev;
	unsigned long  cmd_data_len;

	dev = iser_task->iser_conn->ib_conn.device->ib_device;

	ib_dma_unmap_sg(dev, &data_copy->sg_single, 1,
			(cmd_dir == ISER_DIR_OUT) ?
			DMA_TO_DEVICE : DMA_FROM_DEVICE);

	if (cmd_dir == ISER_DIR_IN) {
		char *mem;
		struct scatterlist *sgl, *sg;
		unsigned char *p, *to;
		unsigned int sg_size;
		int i;

		/* copy back read RDMA to unaligned sg */
		mem = data_copy->copy_buf;

		sgl = (struct scatterlist *)data->buf;
		sg_size = data->size;

		p = mem;
		for_each_sg(sgl, sg, sg_size, i) {
			to = kmap_atomic(sg_page(sg));
			memcpy(to + sg->offset,
			       p,
			       sg->length);
			kunmap_atomic(to);
			p += sg->length;
		}
	}

	cmd_data_len = data->data_len;

	if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
		free_pages((unsigned long)data_copy->copy_buf,
			   ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
	else
		kfree(data_copy->copy_buf);

	data_copy->copy_buf = NULL;
}

#define IS_4K_ALIGNED(addr)	((((unsigned long)addr) & ~MASK_4K) == 0)

/**
 * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
 * and returns the length of resulting physical address array (may be less than
 * the original due to possible compaction).
 *
 * we build a "page vec" under the assumption that the SG meets the RDMA
 * alignment requirements. Other then the first and last SG elements, all
 * the "internal" elements can be compacted into a list whose elements are
 * dma addresses of physical pages. The code supports also the weird case
 * where --few fragments of the same page-- are present in the SG as
 * consecutive elements. Also, it handles one entry SG.
 */

static int iser_sg_to_page_vec(struct iser_data_buf *data,
			       struct ib_device *ibdev, u64 *pages,
			       int *offset, int *data_size)
{
	struct scatterlist *sg, *sgl = (struct scatterlist *)data->buf;
	u64 start_addr, end_addr, page, chunk_start = 0;
	unsigned long total_sz = 0;
	unsigned int dma_len;
	int i, new_chunk, cur_page, last_ent = data->dma_nents - 1;

	/* compute the offset of first element */
	*offset = (u64) sgl[0].offset & ~MASK_4K;

	new_chunk = 1;
	cur_page  = 0;
	for_each_sg(sgl, sg, data->dma_nents, i) {
		start_addr = ib_sg_dma_address(ibdev, sg);
		if (new_chunk)
			chunk_start = start_addr;
		dma_len = ib_sg_dma_len(ibdev, sg);
		end_addr = start_addr + dma_len;
		total_sz += dma_len;

		/* collect page fragments until aligned or end of SG list */
		if (!IS_4K_ALIGNED(end_addr) && i < last_ent) {
			new_chunk = 0;
			continue;
		}
		new_chunk = 1;

		/* address of the first page in the contiguous chunk;
		   masking relevant for the very first SG entry,
		   which might be unaligned */
		page = chunk_start & MASK_4K;
		do {
			pages[cur_page++] = page;
			page += SIZE_4K;
		} while (page < end_addr);
	}

	*data_size = total_sz;
	iser_dbg("page_vec->data_size:%d cur_page %d\n",
		 *data_size, cur_page);
	return cur_page;
}


/**
 * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 * the number of entries which are aligned correctly. Supports the case where
 * consecutive SG elements are actually fragments of the same physcial page.
 */
static int iser_data_buf_aligned_len(struct iser_data_buf *data,
				      struct ib_device *ibdev)
{
	struct scatterlist *sgl, *sg, *next_sg = NULL;
	u64 start_addr, end_addr;
	int i, ret_len, start_check = 0;

	if (data->dma_nents == 1)
		return 1;

	sgl = (struct scatterlist *)data->buf;
	start_addr  = ib_sg_dma_address(ibdev, sgl);

	for_each_sg(sgl, sg, data->dma_nents, i) {
		if (start_check && !IS_4K_ALIGNED(start_addr))
			break;

		next_sg = sg_next(sg);
		if (!next_sg)
			break;

		end_addr    = start_addr + ib_sg_dma_len(ibdev, sg);
		start_addr  = ib_sg_dma_address(ibdev, next_sg);

		if (end_addr == start_addr) {
			start_check = 0;
			continue;
		} else
			start_check = 1;

		if (!IS_4K_ALIGNED(end_addr))
			break;
	}
	ret_len = (next_sg) ? i : i+1;
	iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
		 ret_len, data->dma_nents, data);
	return ret_len;
}

static void iser_data_buf_dump(struct iser_data_buf *data,
			       struct ib_device *ibdev)
{
	struct scatterlist *sgl = (struct scatterlist *)data->buf;
	struct scatterlist *sg;
	int i;

	for_each_sg(sgl, sg, data->dma_nents, i)
		iser_dbg("sg[%d] dma_addr:0x%lX page:0x%p "
			 "off:0x%x sz:0x%x dma_len:0x%x\n",
			 i, (unsigned long)ib_sg_dma_address(ibdev, sg),
			 sg_page(sg), sg->offset,
			 sg->length, ib_sg_dma_len(ibdev, sg));
}

static void iser_dump_page_vec(struct iser_page_vec *page_vec)
{
	int i;

	iser_err("page vec length %d data size %d\n",
		 page_vec->length, page_vec->data_size);
	for (i = 0; i < page_vec->length; i++)
		iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
}

static void iser_page_vec_build(struct iser_data_buf *data,
				struct iser_page_vec *page_vec,
				struct ib_device *ibdev)
{
	int page_vec_len = 0;

	page_vec->length = 0;
	page_vec->offset = 0;

	iser_dbg("Translating sg sz: %d\n", data->dma_nents);
	page_vec_len = iser_sg_to_page_vec(data, ibdev, page_vec->pages,
					   &page_vec->offset,
					   &page_vec->data_size);
	iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents, page_vec_len);

	page_vec->length = page_vec_len;

	if (page_vec_len * SIZE_4K < page_vec->data_size) {
		iser_err("page_vec too short to hold this SG\n");
		iser_data_buf_dump(data, ibdev);
		iser_dump_page_vec(page_vec);
		BUG();
	}
}

int iser_dma_map_task_data(struct iscsi_iser_task *iser_task,
			    struct iser_data_buf *data,
			    enum iser_data_dir iser_dir,
			    enum dma_data_direction dma_dir)
{
	struct ib_device *dev;

	iser_task->dir[iser_dir] = 1;
	dev = iser_task->iser_conn->ib_conn.device->ib_device;

	data->dma_nents = ib_dma_map_sg(dev, data->buf, data->size, dma_dir);
	if (data->dma_nents == 0) {
		iser_err("dma_map_sg failed!!!\n");
		return -EINVAL;
	}
	return 0;
}

void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
			      struct iser_data_buf *data)
{
	struct ib_device *dev;

	dev = iser_task->iser_conn->ib_conn.device->ib_device;
	ib_dma_unmap_sg(dev, data->buf, data->size, DMA_FROM_DEVICE);
}

static int fall_to_bounce_buf(struct iscsi_iser_task *iser_task,
			      struct ib_device *ibdev,
			      struct iser_data_buf *mem,
			      struct iser_data_buf *mem_copy,
			      enum iser_data_dir cmd_dir,
			      int aligned_len)
{
	struct iscsi_conn    *iscsi_conn = iser_task->iser_conn->iscsi_conn;

	iscsi_conn->fmr_unalign_cnt++;
	iser_warn("rdma alignment violation (%d/%d aligned) or FMR not supported\n",
		  aligned_len, mem->size);

	if (iser_debug_level > 0)
		iser_data_buf_dump(mem, ibdev);

	/* unmap the command data before accessing it */
	iser_dma_unmap_task_data(iser_task, mem);

	/* allocate copy buf, if we are writing, copy the */
	/* unaligned scatterlist, dma map the copy        */
	if (iser_start_rdma_unaligned_sg(iser_task, mem, mem_copy, cmd_dir) != 0)
		return -ENOMEM;

	return 0;
}

/**
 * iser_reg_rdma_mem_fmr - Registers memory intended for RDMA,
 * using FMR (if possible) obtaining rkey and va
 *
 * returns 0 on success, errno code on failure
 */
int iser_reg_rdma_mem_fmr(struct iscsi_iser_task *iser_task,
			  enum iser_data_dir cmd_dir)
{
	struct ib_conn *ib_conn = &iser_task->iser_conn->ib_conn;
	struct iser_device   *device = ib_conn->device;
	struct ib_device     *ibdev = device->ib_device;
	struct iser_data_buf *mem = &iser_task->data[cmd_dir];
	struct iser_regd_buf *regd_buf;
	int aligned_len;
	int err;
	int i;
	struct scatterlist *sg;

	regd_buf = &iser_task->rdma_regd[cmd_dir];

	aligned_len = iser_data_buf_aligned_len(mem, ibdev);
	if (aligned_len != mem->dma_nents) {
		err = fall_to_bounce_buf(iser_task, ibdev, mem,
					 &iser_task->data_copy[cmd_dir],
					 cmd_dir, aligned_len);
		if (err) {
			iser_err("failed to allocate bounce buffer\n");
			return err;
		}
		mem = &iser_task->data_copy[cmd_dir];
	}

	/* if there a single dma entry, FMR is not needed */
	if (mem->dma_nents == 1) {
		sg = (struct scatterlist *)mem->buf;

		regd_buf->reg.lkey = device->mr->lkey;
		regd_buf->reg.rkey = device->mr->rkey;
		regd_buf->reg.len  = ib_sg_dma_len(ibdev, &sg[0]);
		regd_buf->reg.va   = ib_sg_dma_address(ibdev, &sg[0]);
		regd_buf->reg.is_mr = 0;

		iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X  "
			 "va: 0x%08lX sz: %ld]\n",
			 (unsigned int)regd_buf->reg.lkey,
			 (unsigned int)regd_buf->reg.rkey,
			 (unsigned long)regd_buf->reg.va,
			 (unsigned long)regd_buf->reg.len);
	} else { /* use FMR for multiple dma entries */
		iser_page_vec_build(mem, ib_conn->fmr.page_vec, ibdev);
		err = iser_reg_page_vec(ib_conn, ib_conn->fmr.page_vec,
					&regd_buf->reg);
		if (err && err != -EAGAIN) {
			iser_data_buf_dump(mem, ibdev);
			iser_err("mem->dma_nents = %d (dlength = 0x%x)\n",
				 mem->dma_nents,
				 ntoh24(iser_task->desc.iscsi_header.dlength));
			iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",
				 ib_conn->fmr.page_vec->data_size,
				 ib_conn->fmr.page_vec->length,
				 ib_conn->fmr.page_vec->offset);
			for (i = 0; i < ib_conn->fmr.page_vec->length; i++)
				iser_err("page_vec[%d] = 0x%llx\n", i,
					 (unsigned long long)ib_conn->fmr.page_vec->pages[i]);
		}
		if (err)
			return err;
	}
	return 0;
}

static inline void
iser_set_dif_domain(struct scsi_cmnd *sc, struct ib_sig_attrs *sig_attrs,
		    struct ib_sig_domain *domain)
{
	domain->sig_type = IB_SIG_TYPE_T10_DIF;
	domain->sig.dif.pi_interval = sc->device->sector_size;
	domain->sig.dif.ref_tag = scsi_get_lba(sc) & 0xffffffff;
	/*
	 * At the moment we hard code those, but in the future
	 * we will take them from sc.
	 */
	domain->sig.dif.apptag_check_mask = 0xffff;
	domain->sig.dif.app_escape = true;
	domain->sig.dif.ref_escape = true;
	if (scsi_get_prot_type(sc) == SCSI_PROT_DIF_TYPE1 ||
	    scsi_get_prot_type(sc) == SCSI_PROT_DIF_TYPE2)
		domain->sig.dif.ref_remap = true;
};

static int
iser_set_sig_attrs(struct scsi_cmnd *sc, struct ib_sig_attrs *sig_attrs)
{
	switch (scsi_get_prot_op(sc)) {
	case SCSI_PROT_WRITE_INSERT:
	case SCSI_PROT_READ_STRIP:
		sig_attrs->mem.sig_type = IB_SIG_TYPE_NONE;
		iser_set_dif_domain(sc, sig_attrs, &sig_attrs->wire);
		sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
		break;
	case SCSI_PROT_READ_INSERT:
	case SCSI_PROT_WRITE_STRIP:
		sig_attrs->wire.sig_type = IB_SIG_TYPE_NONE;
		iser_set_dif_domain(sc, sig_attrs, &sig_attrs->mem);
		/*
		 * At the moment we use this modparam to tell what is
		 * the memory bg_type, in the future we will take it
		 * from sc.
		 */
		sig_attrs->mem.sig.dif.bg_type = iser_pi_guard ? IB_T10DIF_CSUM :
						 IB_T10DIF_CRC;
		break;
	case SCSI_PROT_READ_PASS:
	case SCSI_PROT_WRITE_PASS:
		iser_set_dif_domain(sc, sig_attrs, &sig_attrs->wire);
		sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
		iser_set_dif_domain(sc, sig_attrs, &sig_attrs->mem);
		/*
		 * At the moment we use this modparam to tell what is
		 * the memory bg_type, in the future we will take it
		 * from sc.
		 */
		sig_attrs->mem.sig.dif.bg_type = iser_pi_guard ? IB_T10DIF_CSUM :
						 IB_T10DIF_CRC;
		break;
	default:
		iser_err("Unsupported PI operation %d\n",
			 scsi_get_prot_op(sc));
		return -EINVAL;
	}

	return 0;
}

static int
iser_set_prot_checks(struct scsi_cmnd *sc, u8 *mask)
{
	switch (scsi_get_prot_type(sc)) {
	case SCSI_PROT_DIF_TYPE0:
		break;
	case SCSI_PROT_DIF_TYPE1:
	case SCSI_PROT_DIF_TYPE2:
		*mask = ISER_CHECK_GUARD | ISER_CHECK_REFTAG;
		break;
	case SCSI_PROT_DIF_TYPE3:
		*mask = ISER_CHECK_GUARD;
		break;
	default:
		iser_err("Unsupported protection type %d\n",
			 scsi_get_prot_type(sc));
		return -EINVAL;
	}

	return 0;
}

static int
iser_reg_sig_mr(struct iscsi_iser_task *iser_task,
		struct fast_reg_descriptor *desc, struct ib_sge *data_sge,
		struct ib_sge *prot_sge, struct ib_sge *sig_sge)
{
	struct ib_conn *ib_conn = &iser_task->iser_conn->ib_conn;
	struct iser_pi_context *pi_ctx = desc->pi_ctx;
	struct ib_send_wr sig_wr, inv_wr;
	struct ib_send_wr *bad_wr, *wr = NULL;
	struct ib_sig_attrs sig_attrs;
	int ret;
	u32 key;

	memset(&sig_attrs, 0, sizeof(sig_attrs));
	ret = iser_set_sig_attrs(iser_task->sc, &sig_attrs);
	if (ret)
		goto err;

	ret = iser_set_prot_checks(iser_task->sc, &sig_attrs.check_mask);
	if (ret)
		goto err;

	if (!(desc->reg_indicators & ISER_SIG_KEY_VALID)) {
		memset(&inv_wr, 0, sizeof(inv_wr));
		inv_wr.opcode = IB_WR_LOCAL_INV;
		inv_wr.wr_id = ISER_FASTREG_LI_WRID;
		inv_wr.ex.invalidate_rkey = pi_ctx->sig_mr->rkey;
		wr = &inv_wr;
		/* Bump the key */
		key = (u8)(pi_ctx->sig_mr->rkey & 0x000000FF);
		ib_update_fast_reg_key(pi_ctx->sig_mr, ++key);
	}

	memset(&sig_wr, 0, sizeof(sig_wr));
	sig_wr.opcode = IB_WR_REG_SIG_MR;
	sig_wr.wr_id = ISER_FASTREG_LI_WRID;
	sig_wr.sg_list = data_sge;
	sig_wr.num_sge = 1;
	sig_wr.wr.sig_handover.sig_attrs = &sig_attrs;
	sig_wr.wr.sig_handover.sig_mr = pi_ctx->sig_mr;
	if (scsi_prot_sg_count(iser_task->sc))
		sig_wr.wr.sig_handover.prot = prot_sge;
	sig_wr.wr.sig_handover.access_flags = IB_ACCESS_LOCAL_WRITE |
					      IB_ACCESS_REMOTE_READ |
					      IB_ACCESS_REMOTE_WRITE;

	if (!wr)
		wr = &sig_wr;
	else
		wr->next = &sig_wr;

	ret = ib_post_send(ib_conn->qp, wr, &bad_wr);
	if (ret) {
		iser_err("reg_sig_mr failed, ret:%d\n", ret);
		goto err;
	}
	desc->reg_indicators &= ~ISER_SIG_KEY_VALID;

	sig_sge->lkey = pi_ctx->sig_mr->lkey;
	sig_sge->addr = 0;
	sig_sge->length = data_sge->length + prot_sge->length;
	if (scsi_get_prot_op(iser_task->sc) == SCSI_PROT_WRITE_INSERT ||
	    scsi_get_prot_op(iser_task->sc) == SCSI_PROT_READ_STRIP) {
		sig_sge->length += (data_sge->length /
				   iser_task->sc->device->sector_size) * 8;
	}

	iser_dbg("sig_sge: addr: 0x%llx  length: %u lkey: 0x%x\n",
		 sig_sge->addr, sig_sge->length,
		 sig_sge->lkey);
err:
	return ret;
}

static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
			    struct iser_regd_buf *regd_buf,
			    struct iser_data_buf *mem,
			    enum iser_reg_indicator ind,
			    struct ib_sge *sge)
{
	struct fast_reg_descriptor *desc = regd_buf->reg.mem_h;
	struct ib_conn *ib_conn = &iser_task->iser_conn->ib_conn;
	struct iser_device *device = ib_conn->device;
	struct ib_device *ibdev = device->ib_device;
	struct ib_mr *mr;
	struct ib_fast_reg_page_list *frpl;
	struct ib_send_wr fastreg_wr, inv_wr;
	struct ib_send_wr *bad_wr, *wr = NULL;
	u8 key;
	int ret, offset, size, plen;

	/* if there a single dma entry, dma mr suffices */
	if (mem->dma_nents == 1) {
		struct scatterlist *sg = (struct scatterlist *)mem->buf;

		sge->lkey = device->mr->lkey;
		sge->addr   = ib_sg_dma_address(ibdev, &sg[0]);
		sge->length  = ib_sg_dma_len(ibdev, &sg[0]);

		iser_dbg("Single DMA entry: lkey=0x%x, addr=0x%llx, length=0x%x\n",
			 sge->lkey, sge->addr, sge->length);
		return 0;
	}

	if (ind == ISER_DATA_KEY_VALID) {
		mr = desc->data_mr;
		frpl = desc->data_frpl;
	} else {
		mr = desc->pi_ctx->prot_mr;
		frpl = desc->pi_ctx->prot_frpl;
	}

	plen = iser_sg_to_page_vec(mem, device->ib_device, frpl->page_list,
				   &offset, &size);
	if (plen * SIZE_4K < size) {
		iser_err("fast reg page_list too short to hold this SG\n");
		return -EINVAL;
	}

	if (!(desc->reg_indicators & ind)) {
		memset(&inv_wr, 0, sizeof(inv_wr));
		inv_wr.wr_id = ISER_FASTREG_LI_WRID;
		inv_wr.opcode = IB_WR_LOCAL_INV;
		inv_wr.ex.invalidate_rkey = mr->rkey;
		wr = &inv_wr;
		/* Bump the key */
		key = (u8)(mr->rkey & 0x000000FF);
		ib_update_fast_reg_key(mr, ++key);
	}

	/* Prepare FASTREG WR */
	memset(&fastreg_wr, 0, sizeof(fastreg_wr));
	fastreg_wr.wr_id = ISER_FASTREG_LI_WRID;
	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
	fastreg_wr.wr.fast_reg.iova_start = frpl->page_list[0] + offset;
	fastreg_wr.wr.fast_reg.page_list = frpl;
	fastreg_wr.wr.fast_reg.page_list_len = plen;
	fastreg_wr.wr.fast_reg.page_shift = SHIFT_4K;
	fastreg_wr.wr.fast_reg.length = size;
	fastreg_wr.wr.fast_reg.rkey = mr->rkey;
	fastreg_wr.wr.fast_reg.access_flags = (IB_ACCESS_LOCAL_WRITE  |
					       IB_ACCESS_REMOTE_WRITE |
					       IB_ACCESS_REMOTE_READ);

	if (!wr)
		wr = &fastreg_wr;
	else
		wr->next = &fastreg_wr;

	ret = ib_post_send(ib_conn->qp, wr, &bad_wr);
	if (ret) {
		iser_err("fast registration failed, ret:%d\n", ret);
		return ret;
	}
	desc->reg_indicators &= ~ind;

	sge->lkey = mr->lkey;
	sge->addr = frpl->page_list[0] + offset;
	sge->length = size;

	return ret;
}

/**
 * iser_reg_rdma_mem_fastreg - Registers memory intended for RDMA,
 * using Fast Registration WR (if possible) obtaining rkey and va
 *
 * returns 0 on success, errno code on failure
 */
int iser_reg_rdma_mem_fastreg(struct iscsi_iser_task *iser_task,
			      enum iser_data_dir cmd_dir)
{
	struct ib_conn *ib_conn = &iser_task->iser_conn->ib_conn;
	struct iser_device *device = ib_conn->device;
	struct ib_device *ibdev = device->ib_device;
	struct iser_data_buf *mem = &iser_task->data[cmd_dir];
	struct iser_regd_buf *regd_buf = &iser_task->rdma_regd[cmd_dir];
	struct fast_reg_descriptor *desc = NULL;
	struct ib_sge data_sge;
	int err, aligned_len;
	unsigned long flags;

	aligned_len = iser_data_buf_aligned_len(mem, ibdev);
	if (aligned_len != mem->dma_nents) {
		err = fall_to_bounce_buf(iser_task, ibdev, mem,
					 &iser_task->data_copy[cmd_dir],
					 cmd_dir, aligned_len);
		if (err) {
			iser_err("failed to allocate bounce buffer\n");
			return err;
		}
		mem = &iser_task->data_copy[cmd_dir];
	}

	if (mem->dma_nents != 1 ||
	    scsi_get_prot_op(iser_task->sc) != SCSI_PROT_NORMAL) {
		spin_lock_irqsave(&ib_conn->lock, flags);
		desc = list_first_entry(&ib_conn->fastreg.pool,
					struct fast_reg_descriptor, list);
		list_del(&desc->list);
		spin_unlock_irqrestore(&ib_conn->lock, flags);
		regd_buf->reg.mem_h = desc;
	}

	err = iser_fast_reg_mr(iser_task, regd_buf, mem,
			       ISER_DATA_KEY_VALID, &data_sge);
	if (err)
		goto err_reg;

	if (scsi_get_prot_op(iser_task->sc) != SCSI_PROT_NORMAL) {
		struct ib_sge prot_sge, sig_sge;

		memset(&prot_sge, 0, sizeof(prot_sge));
		if (scsi_prot_sg_count(iser_task->sc)) {
			mem = &iser_task->prot[cmd_dir];
			aligned_len = iser_data_buf_aligned_len(mem, ibdev);
			if (aligned_len != mem->dma_nents) {
				err = fall_to_bounce_buf(iser_task, ibdev, mem,
							 &iser_task->prot_copy[cmd_dir],
							 cmd_dir, aligned_len);
				if (err) {
					iser_err("failed to allocate bounce buffer\n");
					return err;
				}
				mem = &iser_task->prot_copy[cmd_dir];
			}

			err = iser_fast_reg_mr(iser_task, regd_buf, mem,
					       ISER_PROT_KEY_VALID, &prot_sge);
			if (err)
				goto err_reg;
		}

		err = iser_reg_sig_mr(iser_task, desc, &data_sge,
				      &prot_sge, &sig_sge);
		if (err) {
			iser_err("Failed to register signature mr\n");
			return err;
		}
		desc->reg_indicators |= ISER_FASTREG_PROTECTED;

		regd_buf->reg.lkey = sig_sge.lkey;
		regd_buf->reg.rkey = desc->pi_ctx->sig_mr->rkey;
		regd_buf->reg.va = sig_sge.addr;
		regd_buf->reg.len = sig_sge.length;
		regd_buf->reg.is_mr = 1;
	} else {
		if (desc) {
			regd_buf->reg.rkey = desc->data_mr->rkey;
			regd_buf->reg.is_mr = 1;
		} else {
			regd_buf->reg.rkey = device->mr->rkey;
			regd_buf->reg.is_mr = 0;
		}

		regd_buf->reg.lkey = data_sge.lkey;
		regd_buf->reg.va = data_sge.addr;
		regd_buf->reg.len = data_sge.length;
	}

	return 0;
err_reg:
	if (desc) {
		spin_lock_irqsave(&ib_conn->lock, flags);
		list_add_tail(&desc->list, &ib_conn->fastreg.pool);
		spin_unlock_irqrestore(&ib_conn->lock, flags);
	}

	return err;
}