DPDK logo

Elixir Cross Referencer

   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
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
/*-
 *   BSD LICENSE
 *
 *   Copyright 2015 6WIND S.A.
 *   Copyright 2015 Mellanox.
 *
 *   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.
 *     * Neither the name of 6WIND S.A. nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <assert.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>

/* Verbs header. */
/* ISO C doesn't support unnamed structs/unions, disabling -pedantic. */
#ifdef PEDANTIC
#pragma GCC diagnostic ignored "-pedantic"
#endif
#include <infiniband/verbs.h>
#ifdef PEDANTIC
#pragma GCC diagnostic error "-pedantic"
#endif

/* DPDK headers don't like -pedantic. */
#ifdef PEDANTIC
#pragma GCC diagnostic ignored "-pedantic"
#endif
#include <rte_mbuf.h>
#include <rte_mempool.h>
#include <rte_prefetch.h>
#include <rte_common.h>
#include <rte_branch_prediction.h>
#ifdef PEDANTIC
#pragma GCC diagnostic error "-pedantic"
#endif

#include "mlx5.h"
#include "mlx5_utils.h"
#include "mlx5_rxtx.h"
#include "mlx5_defs.h"

/**
 * Manage TX completions.
 *
 * When sending a burst, mlx5_tx_burst() posts several WRs.
 * To improve performance, a completion event is only required once every
 * MLX5_PMD_TX_PER_COMP_REQ sends. Doing so discards completion information
 * for other WRs, but this information would not be used anyway.
 *
 * @param txq
 *   Pointer to TX queue structure.
 *
 * @return
 *   0 on success, -1 on failure.
 */
static int
txq_complete(struct txq *txq)
{
	unsigned int elts_comp = txq->elts_comp;
	unsigned int elts_tail = txq->elts_tail;
	const unsigned int elts_n = txq->elts_n;
	int wcs_n;

	if (unlikely(elts_comp == 0))
		return 0;
#ifdef DEBUG_SEND
	DEBUG("%p: processing %u work requests completions",
	      (void *)txq, elts_comp);
#endif
	wcs_n = txq->if_cq->poll_cnt(txq->cq, elts_comp);
	if (unlikely(wcs_n == 0))
		return 0;
	if (unlikely(wcs_n < 0)) {
		DEBUG("%p: ibv_poll_cq() failed (wcs_n=%d)",
		      (void *)txq, wcs_n);
		return -1;
	}
	elts_comp -= wcs_n;
	assert(elts_comp <= txq->elts_comp);
	/*
	 * Assume WC status is successful as nothing can be done about it
	 * anyway.
	 */
	elts_tail += wcs_n * txq->elts_comp_cd_init;
	if (elts_tail >= elts_n)
		elts_tail -= elts_n;
	txq->elts_tail = elts_tail;
	txq->elts_comp = elts_comp;
	return 0;
}

/**
 * Get Memory Pool (MP) from mbuf. If mbuf is indirect, the pool from which
 * the cloned mbuf is allocated is returned instead.
 *
 * @param buf
 *   Pointer to mbuf.
 *
 * @return
 *   Memory pool where data is located for given mbuf.
 */
static struct rte_mempool *
txq_mb2mp(struct rte_mbuf *buf)
{
	if (unlikely(RTE_MBUF_INDIRECT(buf)))
		return rte_mbuf_from_indirect(buf)->pool;
	return buf->pool;
}

/**
 * Get Memory Region (MR) <-> Memory Pool (MP) association from txq->mp2mr[].
 * Add MP to txq->mp2mr[] if it's not registered yet. If mp2mr[] is full,
 * remove an entry first.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param[in] mp
 *   Memory Pool for which a Memory Region lkey must be returned.
 *
 * @return
 *   mr->lkey on success, (uint32_t)-1 on failure.
 */
static uint32_t
txq_mp2mr(struct txq *txq, const struct rte_mempool *mp)
{
	unsigned int i;
	struct ibv_mr *mr;

	for (i = 0; (i != RTE_DIM(txq->mp2mr)); ++i) {
		if (unlikely(txq->mp2mr[i].mp == NULL)) {
			/* Unknown MP, add a new MR for it. */
			break;
		}
		if (txq->mp2mr[i].mp == mp) {
			assert(txq->mp2mr[i].lkey != (uint32_t)-1);
			assert(txq->mp2mr[i].mr->lkey == txq->mp2mr[i].lkey);
			return txq->mp2mr[i].lkey;
		}
	}
	/* Add a new entry, register MR first. */
	DEBUG("%p: discovered new memory pool \"%s\" (%p)",
	      (void *)txq, mp->name, (const void *)mp);
	mr = ibv_reg_mr(txq->priv->pd,
			(void *)mp->elt_va_start,
			(mp->elt_va_end - mp->elt_va_start),
			(IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE));
	if (unlikely(mr == NULL)) {
		DEBUG("%p: unable to configure MR, ibv_reg_mr() failed.",
		      (void *)txq);
		return (uint32_t)-1;
	}
	if (unlikely(i == RTE_DIM(txq->mp2mr))) {
		/* Table is full, remove oldest entry. */
		DEBUG("%p: MR <-> MP table full, dropping oldest entry.",
		      (void *)txq);
		--i;
		claim_zero(ibv_dereg_mr(txq->mp2mr[0].mr));
		memmove(&txq->mp2mr[0], &txq->mp2mr[1],
			(sizeof(txq->mp2mr) - sizeof(txq->mp2mr[0])));
	}
	/* Store the new entry. */
	txq->mp2mr[i].mp = mp;
	txq->mp2mr[i].mr = mr;
	txq->mp2mr[i].lkey = mr->lkey;
	DEBUG("%p: new MR lkey for MP \"%s\" (%p): 0x%08" PRIu32,
	      (void *)txq, mp->name, (const void *)mp, txq->mp2mr[i].lkey);
	return txq->mp2mr[i].lkey;
}

struct txq_mp2mr_mbuf_check_data {
	const struct rte_mempool *mp;
	int ret;
};

/**
 * Callback function for rte_mempool_obj_iter() to check whether a given
 * mempool object looks like a mbuf.
 *
 * @param[in, out] arg
 *   Context data (struct txq_mp2mr_mbuf_check_data). Contains mempool pointer
 *   and return value.
 * @param[in] start
 *   Object start address.
 * @param[in] end
 *   Object end address.
 * @param index
 *   Unused.
 *
 * @return
 *   Nonzero value when object is not a mbuf.
 */
static void
txq_mp2mr_mbuf_check(void *arg, void *start, void *end,
		     uint32_t index __rte_unused)
{
	struct txq_mp2mr_mbuf_check_data *data = arg;
	struct rte_mbuf *buf =
		(void *)((uintptr_t)start + data->mp->header_size);

	(void)index;
	/* Check whether mbuf structure fits element size and whether mempool
	 * pointer is valid. */
	if (((uintptr_t)end >= (uintptr_t)(buf + 1)) &&
	    (buf->pool == data->mp))
		data->ret = 0;
	else
		data->ret = -1;
}

/**
 * Iterator function for rte_mempool_walk() to register existing mempools and
 * fill the MP to MR cache of a TX queue.
 *
 * @param[in] mp
 *   Memory Pool to register.
 * @param *arg
 *   Pointer to TX queue structure.
 */
void
txq_mp2mr_iter(const struct rte_mempool *mp, void *arg)
{
	struct txq *txq = arg;
	struct txq_mp2mr_mbuf_check_data data = {
		.mp = mp,
		.ret = -1,
	};

	/* Discard empty mempools. */
	if (mp->size == 0)
		return;
	/* Register mempool only if the first element looks like a mbuf. */
	rte_mempool_obj_iter((void *)mp->elt_va_start,
			     1,
			     mp->header_size + mp->elt_size + mp->trailer_size,
			     1,
			     mp->elt_pa,
			     mp->pg_num,
			     mp->pg_shift,
			     txq_mp2mr_mbuf_check,
			     &data);
	if (data.ret)
		return;
	txq_mp2mr(txq, mp);
}

#if MLX5_PMD_SGE_WR_N > 1

/**
 * Copy scattered mbuf contents to a single linear buffer.
 *
 * @param[out] linear
 *   Linear output buffer.
 * @param[in] buf
 *   Scattered input buffer.
 *
 * @return
 *   Number of bytes copied to the output buffer or 0 if not large enough.
 */
static unsigned int
linearize_mbuf(linear_t *linear, struct rte_mbuf *buf)
{
	unsigned int size = 0;
	unsigned int offset;

	do {
		unsigned int len = DATA_LEN(buf);

		offset = size;
		size += len;
		if (unlikely(size > sizeof(*linear)))
			return 0;
		memcpy(&(*linear)[offset],
		       rte_pktmbuf_mtod(buf, uint8_t *),
		       len);
		buf = NEXT(buf);
	} while (buf != NULL);
	return size;
}

/**
 * Handle scattered buffers for mlx5_tx_burst().
 *
 * @param txq
 *   TX queue structure.
 * @param segs
 *   Number of segments in buf.
 * @param elt
 *   TX queue element to fill.
 * @param[in] buf
 *   Buffer to process.
 * @param elts_head
 *   Index of the linear buffer to use if necessary (normally txq->elts_head).
 * @param[out] sges
 *   Array filled with SGEs on success.
 *
 * @return
 *   A structure containing the processed packet size in bytes and the
 *   number of SGEs. Both fields are set to (unsigned int)-1 in case of
 *   failure.
 */
static struct tx_burst_sg_ret {
	unsigned int length;
	unsigned int num;
}
tx_burst_sg(struct txq *txq, unsigned int segs, struct txq_elt *elt,
	    struct rte_mbuf *buf, unsigned int elts_head,
	    struct ibv_sge (*sges)[MLX5_PMD_SGE_WR_N])
{
	unsigned int sent_size = 0;
	unsigned int j;
	int linearize = 0;

	/* When there are too many segments, extra segments are
	 * linearized in the last SGE. */
	if (unlikely(segs > RTE_DIM(*sges))) {
		segs = (RTE_DIM(*sges) - 1);
		linearize = 1;
	}
	/* Update element. */
	elt->buf = buf;
	/* Register segments as SGEs. */
	for (j = 0; (j != segs); ++j) {
		struct ibv_sge *sge = &(*sges)[j];
		uint32_t lkey;

		/* Retrieve Memory Region key for this memory pool. */
		lkey = txq_mp2mr(txq, txq_mb2mp(buf));
		if (unlikely(lkey == (uint32_t)-1)) {
			/* MR does not exist. */
			DEBUG("%p: unable to get MP <-> MR association",
			      (void *)txq);
			/* Clean up TX element. */
			elt->buf = NULL;
			goto stop;
		}
		/* Update SGE. */
		sge->addr = rte_pktmbuf_mtod(buf, uintptr_t);
		if (txq->priv->vf)
			rte_prefetch0((volatile void *)
				      (uintptr_t)sge->addr);
		sge->length = DATA_LEN(buf);
		sge->lkey = lkey;
		sent_size += sge->length;
		buf = NEXT(buf);
	}
	/* If buf is not NULL here and is not going to be linearized,
	 * nb_segs is not valid. */
	assert(j == segs);
	assert((buf == NULL) || (linearize));
	/* Linearize extra segments. */
	if (linearize) {
		struct ibv_sge *sge = &(*sges)[segs];
		linear_t *linear = &(*txq->elts_linear)[elts_head];
		unsigned int size = linearize_mbuf(linear, buf);

		assert(segs == (RTE_DIM(*sges) - 1));
		if (size == 0) {
			/* Invalid packet. */
			DEBUG("%p: packet too large to be linearized.",
			      (void *)txq);
			/* Clean up TX element. */
			elt->buf = NULL;
			goto stop;
		}
		/* If MLX5_PMD_SGE_WR_N is 1, free mbuf immediately. */
		if (RTE_DIM(*sges) == 1) {
			do {
				struct rte_mbuf *next = NEXT(buf);

				rte_pktmbuf_free_seg(buf);
				buf = next;
			} while (buf != NULL);
			elt->buf = NULL;
		}
		/* Update SGE. */
		sge->addr = (uintptr_t)&(*linear)[0];
		sge->length = size;
		sge->lkey = txq->mr_linear->lkey;
		sent_size += size;
		/* Include last segment. */
		segs++;
	}
	return (struct tx_burst_sg_ret){
		.length = sent_size,
		.num = segs,
	};
stop:
	return (struct tx_burst_sg_ret){
		.length = -1,
		.num = -1,
	};
}

#endif /* MLX5_PMD_SGE_WR_N > 1 */

/**
 * DPDK callback for TX.
 *
 * @param dpdk_txq
 *   Generic pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 *
 * @return
 *   Number of packets successfully transmitted (<= pkts_n).
 */
uint16_t
mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
	struct txq *txq = (struct txq *)dpdk_txq;
	unsigned int elts_head = txq->elts_head;
	const unsigned int elts_n = txq->elts_n;
	unsigned int elts_comp_cd = txq->elts_comp_cd;
	unsigned int elts_comp = 0;
	unsigned int i;
	unsigned int max;
	int err;

	assert(elts_comp_cd != 0);
	txq_complete(txq);
	max = (elts_n - (elts_head - txq->elts_tail));
	if (max > elts_n)
		max -= elts_n;
	assert(max >= 1);
	assert(max <= elts_n);
	/* Always leave one free entry in the ring. */
	--max;
	if (max == 0)
		return 0;
	if (max > pkts_n)
		max = pkts_n;
	for (i = 0; (i != max); ++i) {
		struct rte_mbuf *buf = pkts[i];
		unsigned int elts_head_next =
			(((elts_head + 1) == elts_n) ? 0 : elts_head + 1);
		struct txq_elt *elt_next = &(*txq->elts)[elts_head_next];
		struct txq_elt *elt = &(*txq->elts)[elts_head];
		unsigned int segs = NB_SEGS(buf);
#ifdef MLX5_PMD_SOFT_COUNTERS
		unsigned int sent_size = 0;
#endif
		uint32_t send_flags = 0;

		/* Clean up old buffer. */
		if (likely(elt->buf != NULL)) {
			struct rte_mbuf *tmp = elt->buf;

			/* Faster than rte_pktmbuf_free(). */
			do {
				struct rte_mbuf *next = NEXT(tmp);

				rte_pktmbuf_free_seg(tmp);
				tmp = next;
			} while (tmp != NULL);
		}
		/* Request TX completion. */
		if (unlikely(--elts_comp_cd == 0)) {
			elts_comp_cd = txq->elts_comp_cd_init;
			++elts_comp;
			send_flags |= IBV_EXP_QP_BURST_SIGNALED;
		}
		/* Should we enable HW CKSUM offload */
		if (buf->ol_flags &
		    (PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM | PKT_TX_UDP_CKSUM)) {
			send_flags |= IBV_EXP_QP_BURST_IP_CSUM;
			/* HW does not support checksum offloads at arbitrary
			 * offsets but automatically recognizes the packet
			 * type. For inner L3/L4 checksums, only VXLAN (UDP)
			 * tunnels are currently supported. */
			if (RTE_ETH_IS_TUNNEL_PKT(buf->packet_type))
				send_flags |= IBV_EXP_QP_BURST_TUNNEL;
		}
		if (likely(segs == 1)) {
			uintptr_t addr;
			uint32_t length;
			uint32_t lkey;

			/* Retrieve buffer information. */
			addr = rte_pktmbuf_mtod(buf, uintptr_t);
			length = DATA_LEN(buf);
			/* Retrieve Memory Region key for this memory pool. */
			lkey = txq_mp2mr(txq, txq_mb2mp(buf));
			if (unlikely(lkey == (uint32_t)-1)) {
				/* MR does not exist. */
				DEBUG("%p: unable to get MP <-> MR"
				      " association", (void *)txq);
				/* Clean up TX element. */
				elt->buf = NULL;
				goto stop;
			}
			/* Update element. */
			elt->buf = buf;
			if (txq->priv->vf)
				rte_prefetch0((volatile void *)
					      (uintptr_t)addr);
			RTE_MBUF_PREFETCH_TO_FREE(elt_next->buf);
			/* Put packet into send queue. */
#if MLX5_PMD_MAX_INLINE > 0
			if (length <= txq->max_inline)
				err = txq->if_qp->send_pending_inline
					(txq->qp,
					 (void *)addr,
					 length,
					 send_flags);
			else
#endif
				err = txq->if_qp->send_pending
					(txq->qp,
					 addr,
					 length,
					 lkey,
					 send_flags);
			if (unlikely(err))
				goto stop;
#ifdef MLX5_PMD_SOFT_COUNTERS
			sent_size += length;
#endif
		} else {
#if MLX5_PMD_SGE_WR_N > 1
			struct ibv_sge sges[MLX5_PMD_SGE_WR_N];
			struct tx_burst_sg_ret ret;

			ret = tx_burst_sg(txq, segs, elt, buf, elts_head,
					  &sges);
			if (ret.length == (unsigned int)-1)
				goto stop;
			RTE_MBUF_PREFETCH_TO_FREE(elt_next->buf);
			/* Put SG list into send queue. */
			err = txq->if_qp->send_pending_sg_list
				(txq->qp,
				 sges,
				 ret.num,
				 send_flags);
			if (unlikely(err))
				goto stop;
#ifdef MLX5_PMD_SOFT_COUNTERS
			sent_size += ret.length;
#endif
#else /* MLX5_PMD_SGE_WR_N > 1 */
			DEBUG("%p: TX scattered buffers support not"
			      " compiled in", (void *)txq);
			goto stop;
#endif /* MLX5_PMD_SGE_WR_N > 1 */
		}
		elts_head = elts_head_next;
#ifdef MLX5_PMD_SOFT_COUNTERS
		/* Increment sent bytes counter. */
		txq->stats.obytes += sent_size;
#endif
	}
stop:
	/* Take a shortcut if nothing must be sent. */
	if (unlikely(i == 0))
		return 0;
#ifdef MLX5_PMD_SOFT_COUNTERS
	/* Increment sent packets counter. */
	txq->stats.opackets += i;
#endif
	/* Ring QP doorbell. */
	err = txq->if_qp->send_flush(txq->qp);
	if (unlikely(err)) {
		/* A nonzero value is not supposed to be returned.
		 * Nothing can be done about it. */
		DEBUG("%p: send_flush() failed with error %d",
		      (void *)txq, err);
	}
	txq->elts_head = elts_head;
	txq->elts_comp += elts_comp;
	txq->elts_comp_cd = elts_comp_cd;
	return i;
}

/**
 * Translate RX completion flags to packet type.
 *
 * @param flags
 *   RX completion flags returned by poll_length_flags().
 *
 * @return
 *   Packet type for struct rte_mbuf.
 */
static inline uint32_t
rxq_cq_to_pkt_type(uint32_t flags)
{
	uint32_t pkt_type;

	if (flags & IBV_EXP_CQ_RX_TUNNEL_PACKET)
		pkt_type =
			TRANSPOSE(flags,
				  IBV_EXP_CQ_RX_OUTER_IPV4_PACKET,
				  RTE_PTYPE_L3_IPV4) |
			TRANSPOSE(flags,
				  IBV_EXP_CQ_RX_OUTER_IPV6_PACKET,
				  RTE_PTYPE_L3_IPV6) |
			TRANSPOSE(flags,
				  IBV_EXP_CQ_RX_IPV4_PACKET,
				  RTE_PTYPE_INNER_L3_IPV4) |
			TRANSPOSE(flags,
				  IBV_EXP_CQ_RX_IPV6_PACKET,
				  RTE_PTYPE_INNER_L3_IPV6);
	else
		pkt_type =
			TRANSPOSE(flags,
				  IBV_EXP_CQ_RX_IPV4_PACKET,
				  RTE_PTYPE_L3_IPV4) |
			TRANSPOSE(flags,
				  IBV_EXP_CQ_RX_IPV6_PACKET,
				  RTE_PTYPE_L3_IPV6);
	return pkt_type;
}

/**
 * Translate RX completion flags to offload flags.
 *
 * @param[in] rxq
 *   Pointer to RX queue structure.
 * @param flags
 *   RX completion flags returned by poll_length_flags().
 *
 * @return
 *   Offload flags (ol_flags) for struct rte_mbuf.
 */
static inline uint32_t
rxq_cq_to_ol_flags(const struct rxq *rxq, uint32_t flags)
{
	uint32_t ol_flags = 0;

	if (rxq->csum)
		ol_flags |=
			TRANSPOSE(~flags,
				  IBV_EXP_CQ_RX_IP_CSUM_OK,
				  PKT_RX_IP_CKSUM_BAD) |
			TRANSPOSE(~flags,
				  IBV_EXP_CQ_RX_TCP_UDP_CSUM_OK,
				  PKT_RX_L4_CKSUM_BAD);
	/*
	 * PKT_RX_IP_CKSUM_BAD and PKT_RX_L4_CKSUM_BAD are used in place
	 * of PKT_RX_EIP_CKSUM_BAD because the latter is not functional
	 * (its value is 0).
	 */
	if ((flags & IBV_EXP_CQ_RX_TUNNEL_PACKET) && (rxq->csum_l2tun))
		ol_flags |=
			TRANSPOSE(~flags,
				  IBV_EXP_CQ_RX_OUTER_IP_CSUM_OK,
				  PKT_RX_IP_CKSUM_BAD) |
			TRANSPOSE(~flags,
				  IBV_EXP_CQ_RX_OUTER_TCP_UDP_CSUM_OK,
				  PKT_RX_L4_CKSUM_BAD);
	return ol_flags;
}

/**
 * DPDK callback for RX with scattered packets support.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
uint16_t
mlx5_rx_burst_sp(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
	struct rxq *rxq = (struct rxq *)dpdk_rxq;
	struct rxq_elt_sp (*elts)[rxq->elts_n] = rxq->elts.sp;
	const unsigned int elts_n = rxq->elts_n;
	unsigned int elts_head = rxq->elts_head;
	unsigned int i;
	unsigned int pkts_ret = 0;
	int ret;

	if (unlikely(!rxq->sp))
		return mlx5_rx_burst(dpdk_rxq, pkts, pkts_n);
	if (unlikely(elts == NULL)) /* See RTE_DEV_CMD_SET_MTU. */
		return 0;
	for (i = 0; (i != pkts_n); ++i) {
		struct rxq_elt_sp *elt = &(*elts)[elts_head];
		unsigned int len;
		unsigned int pkt_buf_len;
		struct rte_mbuf *pkt_buf = NULL; /* Buffer returned in pkts. */
		struct rte_mbuf **pkt_buf_next = &pkt_buf;
		unsigned int seg_headroom = RTE_PKTMBUF_HEADROOM;
		unsigned int j = 0;
		uint32_t flags;

		/* Sanity checks. */
		assert(elts_head < rxq->elts_n);
		assert(rxq->elts_head < rxq->elts_n);
		ret = rxq->if_cq->poll_length_flags(rxq->cq, NULL, NULL,
						    &flags);
		if (unlikely(ret < 0)) {
			struct ibv_wc wc;
			int wcs_n;

			DEBUG("rxq=%p, poll_length() failed (ret=%d)",
			      (void *)rxq, ret);
			/* ibv_poll_cq() must be used in case of failure. */
			wcs_n = ibv_poll_cq(rxq->cq, 1, &wc);
			if (unlikely(wcs_n == 0))
				break;
			if (unlikely(wcs_n < 0)) {
				DEBUG("rxq=%p, ibv_poll_cq() failed (wcs_n=%d)",
				      (void *)rxq, wcs_n);
				break;
			}
			assert(wcs_n == 1);
			if (unlikely(wc.status != IBV_WC_SUCCESS)) {
				/* Whatever, just repost the offending WR. */
				DEBUG("rxq=%p, wr_id=%" PRIu64 ": bad work"
				      " completion status (%d): %s",
				      (void *)rxq, wc.wr_id, wc.status,
				      ibv_wc_status_str(wc.status));
#ifdef MLX5_PMD_SOFT_COUNTERS
				/* Increment dropped packets counter. */
				++rxq->stats.idropped;
#endif
				goto repost;
			}
			ret = wc.byte_len;
		}
		if (ret == 0)
			break;
		len = ret;
		pkt_buf_len = len;
		/*
		 * Replace spent segments with new ones, concatenate and
		 * return them as pkt_buf.
		 */
		while (1) {
			struct ibv_sge *sge = &elt->sges[j];
			struct rte_mbuf *seg = elt->bufs[j];
			struct rte_mbuf *rep;
			unsigned int seg_tailroom;

			assert(seg != NULL);
			/*
			 * Fetch initial bytes of packet descriptor into a
			 * cacheline while allocating rep.
			 */
			rte_prefetch0(seg);
			rep = __rte_mbuf_raw_alloc(rxq->mp);
			if (unlikely(rep == NULL)) {
				/*
				 * Unable to allocate a replacement mbuf,
				 * repost WR.
				 */
				DEBUG("rxq=%p: can't allocate a new mbuf",
				      (void *)rxq);
				if (pkt_buf != NULL) {
					*pkt_buf_next = NULL;
					rte_pktmbuf_free(pkt_buf);
				}
				/* Increment out of memory counters. */
				++rxq->stats.rx_nombuf;
				++rxq->priv->dev->data->rx_mbuf_alloc_failed;
				goto repost;
			}
#ifndef NDEBUG
			/* Poison user-modifiable fields in rep. */
			NEXT(rep) = (void *)((uintptr_t)-1);
			SET_DATA_OFF(rep, 0xdead);
			DATA_LEN(rep) = 0xd00d;
			PKT_LEN(rep) = 0xdeadd00d;
			NB_SEGS(rep) = 0x2a;
			PORT(rep) = 0x2a;
			rep->ol_flags = -1;
#endif
			assert(rep->buf_len == seg->buf_len);
			assert(rep->buf_len == rxq->mb_len);
			/* Reconfigure sge to use rep instead of seg. */
			assert(sge->lkey == rxq->mr->lkey);
			sge->addr = ((uintptr_t)rep->buf_addr + seg_headroom);
			elt->bufs[j] = rep;
			++j;
			/* Update pkt_buf if it's the first segment, or link
			 * seg to the previous one and update pkt_buf_next. */
			*pkt_buf_next = seg;
			pkt_buf_next = &NEXT(seg);
			/* Update seg information. */
			seg_tailroom = (seg->buf_len - seg_headroom);
			assert(sge->length == seg_tailroom);
			SET_DATA_OFF(seg, seg_headroom);
			if (likely(len <= seg_tailroom)) {
				/* Last segment. */
				DATA_LEN(seg) = len;
				PKT_LEN(seg) = len;
				/* Sanity check. */
				assert(rte_pktmbuf_headroom(seg) ==
				       seg_headroom);
				assert(rte_pktmbuf_tailroom(seg) ==
				       (seg_tailroom - len));
				break;
			}
			DATA_LEN(seg) = seg_tailroom;
			PKT_LEN(seg) = seg_tailroom;
			/* Sanity check. */
			assert(rte_pktmbuf_headroom(seg) == seg_headroom);
			assert(rte_pktmbuf_tailroom(seg) == 0);
			/* Fix len and clear headroom for next segments. */
			len -= seg_tailroom;
			seg_headroom = 0;
		}
		/* Update head and tail segments. */
		*pkt_buf_next = NULL;
		assert(pkt_buf != NULL);
		assert(j != 0);
		NB_SEGS(pkt_buf) = j;
		PORT(pkt_buf) = rxq->port_id;
		PKT_LEN(pkt_buf) = pkt_buf_len;
		pkt_buf->packet_type = rxq_cq_to_pkt_type(flags);
		pkt_buf->ol_flags = rxq_cq_to_ol_flags(rxq, flags);

		/* Return packet. */
		*(pkts++) = pkt_buf;
		++pkts_ret;
#ifdef MLX5_PMD_SOFT_COUNTERS
		/* Increment bytes counter. */
		rxq->stats.ibytes += pkt_buf_len;
#endif
repost:
		ret = rxq->if_wq->recv_sg_list(rxq->wq,
					       elt->sges,
					       RTE_DIM(elt->sges));
		if (unlikely(ret)) {
			/* Inability to repost WRs is fatal. */
			DEBUG("%p: recv_sg_list(): failed (ret=%d)",
			      (void *)rxq->priv,
			      ret);
			abort();
		}
		if (++elts_head >= elts_n)
			elts_head = 0;
		continue;
	}
	if (unlikely(i == 0))
		return 0;
	rxq->elts_head = elts_head;
#ifdef MLX5_PMD_SOFT_COUNTERS
	/* Increment packets counter. */
	rxq->stats.ipackets += pkts_ret;
#endif
	return pkts_ret;
}

/**
 * DPDK callback for RX.
 *
 * The following function is the same as mlx5_rx_burst_sp(), except it doesn't
 * manage scattered packets. Improves performance when MRU is lower than the
 * size of the first segment.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
uint16_t
mlx5_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
	struct rxq *rxq = (struct rxq *)dpdk_rxq;
	struct rxq_elt (*elts)[rxq->elts_n] = rxq->elts.no_sp;
	const unsigned int elts_n = rxq->elts_n;
	unsigned int elts_head = rxq->elts_head;
	struct ibv_sge sges[pkts_n];
	unsigned int i;
	unsigned int pkts_ret = 0;
	int ret;

	if (unlikely(rxq->sp))
		return mlx5_rx_burst_sp(dpdk_rxq, pkts, pkts_n);
	for (i = 0; (i != pkts_n); ++i) {
		struct rxq_elt *elt = &(*elts)[elts_head];
		unsigned int len;
		struct rte_mbuf *seg = elt->buf;
		struct rte_mbuf *rep;
		uint32_t flags;

		/* Sanity checks. */
		assert(seg != NULL);
		assert(elts_head < rxq->elts_n);
		assert(rxq->elts_head < rxq->elts_n);
		/*
		 * Fetch initial bytes of packet descriptor into a
		 * cacheline while allocating rep.
		 */
		rte_prefetch0(seg);
		rte_prefetch0(&seg->cacheline1);
		ret = rxq->if_cq->poll_length_flags(rxq->cq, NULL, NULL,
						    &flags);
		if (unlikely(ret < 0)) {
			struct ibv_wc wc;
			int wcs_n;

			DEBUG("rxq=%p, poll_length() failed (ret=%d)",
			      (void *)rxq, ret);
			/* ibv_poll_cq() must be used in case of failure. */
			wcs_n = ibv_poll_cq(rxq->cq, 1, &wc);
			if (unlikely(wcs_n == 0))
				break;
			if (unlikely(wcs_n < 0)) {
				DEBUG("rxq=%p, ibv_poll_cq() failed (wcs_n=%d)",
				      (void *)rxq, wcs_n);
				break;
			}
			assert(wcs_n == 1);
			if (unlikely(wc.status != IBV_WC_SUCCESS)) {
				/* Whatever, just repost the offending WR. */
				DEBUG("rxq=%p, wr_id=%" PRIu64 ": bad work"
				      " completion status (%d): %s",
				      (void *)rxq, wc.wr_id, wc.status,
				      ibv_wc_status_str(wc.status));
#ifdef MLX5_PMD_SOFT_COUNTERS
				/* Increment dropped packets counter. */
				++rxq->stats.idropped;
#endif
				/* Add SGE to array for repost. */
				sges[i] = elt->sge;
				goto repost;
			}
			ret = wc.byte_len;
		}
		if (ret == 0)
			break;
		len = ret;
		rep = __rte_mbuf_raw_alloc(rxq->mp);
		if (unlikely(rep == NULL)) {
			/*
			 * Unable to allocate a replacement mbuf,
			 * repost WR.
			 */
			DEBUG("rxq=%p: can't allocate a new mbuf",
			      (void *)rxq);
			/* Increment out of memory counters. */
			++rxq->stats.rx_nombuf;
			++rxq->priv->dev->data->rx_mbuf_alloc_failed;
			goto repost;
		}

		/* Reconfigure sge to use rep instead of seg. */
		elt->sge.addr = (uintptr_t)rep->buf_addr + RTE_PKTMBUF_HEADROOM;
		assert(elt->sge.lkey == rxq->mr->lkey);
		elt->buf = rep;

		/* Add SGE to array for repost. */
		sges[i] = elt->sge;

		/* Update seg information. */
		SET_DATA_OFF(seg, RTE_PKTMBUF_HEADROOM);
		NB_SEGS(seg) = 1;
		PORT(seg) = rxq->port_id;
		NEXT(seg) = NULL;
		PKT_LEN(seg) = len;
		DATA_LEN(seg) = len;
		seg->packet_type = rxq_cq_to_pkt_type(flags);
		seg->ol_flags = rxq_cq_to_ol_flags(rxq, flags);

		/* Return packet. */
		*(pkts++) = seg;
		++pkts_ret;
#ifdef MLX5_PMD_SOFT_COUNTERS
		/* Increment bytes counter. */
		rxq->stats.ibytes += len;
#endif
repost:
		if (++elts_head >= elts_n)
			elts_head = 0;
		continue;
	}
	if (unlikely(i == 0))
		return 0;
	/* Repost WRs. */
#ifdef DEBUG_RECV
	DEBUG("%p: reposting %u WRs", (void *)rxq, i);
#endif
	ret = rxq->if_wq->recv_burst(rxq->wq, sges, i);
	if (unlikely(ret)) {
		/* Inability to repost WRs is fatal. */
		DEBUG("%p: recv_burst(): failed (ret=%d)",
		      (void *)rxq->priv,
		      ret);
		abort();
	}
	rxq->elts_head = elts_head;
#ifdef MLX5_PMD_SOFT_COUNTERS
	/* Increment packets counter. */
	rxq->stats.ipackets += pkts_ret;
#endif
	return pkts_ret;
}

/**
 * Dummy DPDK callback for TX.
 *
 * This function is used to temporarily replace the real callback during
 * unsafe control operations on the queue, or in case of error.
 *
 * @param dpdk_txq
 *   Generic pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 *
 * @return
 *   Number of packets successfully transmitted (<= pkts_n).
 */
uint16_t
removed_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
	(void)dpdk_txq;
	(void)pkts;
	(void)pkts_n;
	return 0;
}

/**
 * Dummy DPDK callback for RX.
 *
 * This function is used to temporarily replace the real callback during
 * unsafe control operations on the queue, or in case of error.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
uint16_t
removed_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
	(void)dpdk_rxq;
	(void)pkts;
	(void)pkts_n;
	return 0;
}