net/smc/smc_ib.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Shared Memory Communications over RDMA (SMC-R) and RoCE
   4  *
   5  *  IB infrastructure:
   6  *  Establish SMC-R as an Infiniband Client to be notified about added and
   7  *  removed IB devices of type RDMA.
   8  *  Determine device and port characteristics for these IB devices.
   9  *
  10  *  Copyright IBM Corp. 2016
  11  *
  12  *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
  13  */
  14
  15 #include <linux/random.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/scatterlist.h>
  18 #include <rdma/ib_verbs.h>
  19
  20 #include "smc_pnet.h"
  21 #include "smc_ib.h"
  22 #include "smc_core.h"
  23 #include "smc_wr.h"
  24 #include "smc.h"
  25
  26 #define SMC_MAX_CQE 32766       /* max. # of completion queue elements */
  27
  28 #define SMC_QP_MIN_RNR_TIMER            5
  29 #define SMC_QP_TIMEOUT                  15 /* 4096 * 2 ** timeout usec */
  30 #define SMC_QP_RETRY_CNT                        7 /* 7: infinite */
  31 #define SMC_QP_RNR_RETRY                        7 /* 7: infinite */
  32
  33 struct smc_ib_devices smc_ib_devices = {        /* smc-registered ib devices */
  34         .lock = __SPIN_LOCK_UNLOCKED(smc_ib_devices.lock),
  35         .list = LIST_HEAD_INIT(smc_ib_devices.list),
  36 };
  37
  38 #define SMC_LOCAL_SYSTEMID_RESET        "%%%%%%%"
  39
  40 u8 local_systemid[SMC_SYSTEMID_LEN] = SMC_LOCAL_SYSTEMID_RESET; /* unique system
  41                                                                  * identifier
  42                                                                  */
  43
  44 static int smc_ib_modify_qp_init(struct smc_link *lnk)
  45 {
  46         struct ib_qp_attr qp_attr;
  47
  48         memset(&qp_attr, 0, sizeof(qp_attr));
  49         qp_attr.qp_state = IB_QPS_INIT;
  50         qp_attr.pkey_index = 0;
  51         qp_attr.port_num = lnk->ibport;
  52         qp_attr.qp_access_flags = IB_ACCESS_LOCAL_WRITE
  53                                 | IB_ACCESS_REMOTE_WRITE;
  54         return ib_modify_qp(lnk->roce_qp, &qp_attr,
  55                             IB_QP_STATE | IB_QP_PKEY_INDEX |
  56                             IB_QP_ACCESS_FLAGS | IB_QP_PORT);
  57 }
  58
  59 static int smc_ib_modify_qp_rtr(struct smc_link *lnk)
  60 {
  61         enum ib_qp_attr_mask qp_attr_mask =
  62                 IB_QP_STATE | IB_QP_AV | IB_QP_PATH_MTU | IB_QP_DEST_QPN |
  63                 IB_QP_RQ_PSN | IB_QP_MAX_DEST_RD_ATOMIC | IB_QP_MIN_RNR_TIMER;
  64         struct ib_qp_attr qp_attr;
  65
  66         memset(&qp_attr, 0, sizeof(qp_attr));
  67         qp_attr.qp_state = IB_QPS_RTR;
  68         qp_attr.path_mtu = min(lnk->path_mtu, lnk->peer_mtu);
  69         qp_attr.ah_attr.type = RDMA_AH_ATTR_TYPE_ROCE;
  70         rdma_ah_set_port_num(&qp_attr.ah_attr, lnk->ibport);
  71         rdma_ah_set_grh(&qp_attr.ah_attr, NULL, 0, 0, 1, 0);
  72         rdma_ah_set_dgid_raw(&qp_attr.ah_attr, lnk->peer_gid);
  73         memcpy(&qp_attr.ah_attr.roce.dmac, lnk->peer_mac,
  74                sizeof(lnk->peer_mac));
  75         qp_attr.dest_qp_num = lnk->peer_qpn;
  76         qp_attr.rq_psn = lnk->peer_psn; /* starting receive packet seq # */
  77         qp_attr.max_dest_rd_atomic = 1; /* max # of resources for incoming
  78                                          * requests
  79                                          */
  80         qp_attr.min_rnr_timer = SMC_QP_MIN_RNR_TIMER;
  81
  82         return ib_modify_qp(lnk->roce_qp, &qp_attr, qp_attr_mask);
  83 }
  84
  85 int smc_ib_modify_qp_rts(struct smc_link *lnk)
  86 {
  87         struct ib_qp_attr qp_attr;
  88
  89         memset(&qp_attr, 0, sizeof(qp_attr));
  90         qp_attr.qp_state = IB_QPS_RTS;
  91         qp_attr.timeout = SMC_QP_TIMEOUT;       /* local ack timeout */
  92         qp_attr.retry_cnt = SMC_QP_RETRY_CNT;   /* retry count */
  93         qp_attr.rnr_retry = SMC_QP_RNR_RETRY;   /* RNR retries, 7=infinite */
  94         qp_attr.sq_psn = lnk->psn_initial;      /* starting send packet seq # */
  95         qp_attr.max_rd_atomic = 1;      /* # of outstanding RDMA reads and
  96                                          * atomic ops allowed
  97                                          */
  98         return ib_modify_qp(lnk->roce_qp, &qp_attr,
  99                             IB_QP_STATE | IB_QP_TIMEOUT | IB_QP_RETRY_CNT |
 100                             IB_QP_SQ_PSN | IB_QP_RNR_RETRY |
 101                             IB_QP_MAX_QP_RD_ATOMIC);
 102 }
 103
 104 int smc_ib_modify_qp_reset(struct smc_link *lnk)
 105 {
 106         struct ib_qp_attr qp_attr;
 107
 108         memset(&qp_attr, 0, sizeof(qp_attr));
 109         qp_attr.qp_state = IB_QPS_RESET;
 110         return ib_modify_qp(lnk->roce_qp, &qp_attr, IB_QP_STATE);
 111 }
 112
 113 int smc_ib_ready_link(struct smc_link *lnk)
 114 {
 115         struct smc_link_group *lgr =
 116                 container_of(lnk, struct smc_link_group, lnk[0]);
 117         int rc = 0;
 118
 119         rc = smc_ib_modify_qp_init(lnk);
 120         if (rc)
 121                 goto out;
 122
 123         rc = smc_ib_modify_qp_rtr(lnk);
 124         if (rc)
 125                 goto out;
 126         smc_wr_remember_qp_attr(lnk);
 127         rc = ib_req_notify_cq(lnk->smcibdev->roce_cq_recv,
 128                               IB_CQ_SOLICITED_MASK);
 129         if (rc)
 130                 goto out;
 131         rc = smc_wr_rx_post_init(lnk);
 132         if (rc)
 133                 goto out;
 134         smc_wr_remember_qp_attr(lnk);
 135
 136         if (lgr->role == SMC_SERV) {
 137                 rc = smc_ib_modify_qp_rts(lnk);
 138                 if (rc)
 139                         goto out;
 140                 smc_wr_remember_qp_attr(lnk);
 141         }
 142 out:
 143         return rc;
 144 }
 145
 146 /* process context wrapper for might_sleep smc_ib_remember_port_attr */
 147 static void smc_ib_port_event_work(struct work_struct *work)
 148 {
 149         struct smc_ib_device *smcibdev = container_of(
 150                 work, struct smc_ib_device, port_event_work);
 151         u8 port_idx;
 152
 153         for_each_set_bit(port_idx, &smcibdev->port_event_mask, SMC_MAX_PORTS) {
 154                 smc_ib_remember_port_attr(smcibdev, port_idx + 1);
 155                 clear_bit(port_idx, &smcibdev->port_event_mask);
 156         }
 157 }
 158
 159 /* can be called in IRQ context */
 160 static void smc_ib_global_event_handler(struct ib_event_handler *handler,
 161                                         struct ib_event *ibevent)
 162 {
 163         struct smc_ib_device *smcibdev;
 164         u8 port_idx;
 165
 166         smcibdev = container_of(handler, struct smc_ib_device, event_handler);
 167
 168         switch (ibevent->event) {
 169         case IB_EVENT_PORT_ERR:
 170                 port_idx = ibevent->element.port_num - 1;
 171                 set_bit(port_idx, &smcibdev->port_event_mask);
 172                 schedule_work(&smcibdev->port_event_work);
 173                 /* fall through */
 174         case IB_EVENT_DEVICE_FATAL:
 175                 /* tbd in follow-on patch:
 176                  * abnormal close of corresponding connections
 177                  */
 178                 break;
 179         case IB_EVENT_PORT_ACTIVE:
 180                 port_idx = ibevent->element.port_num - 1;
 181                 set_bit(port_idx, &smcibdev->port_event_mask);
 182                 schedule_work(&smcibdev->port_event_work);
 183                 break;
 184         default:
 185                 break;
 186         }
 187 }
 188
 189 void smc_ib_dealloc_protection_domain(struct smc_link *lnk)
 190 {
 191         ib_dealloc_pd(lnk->roce_pd);
 192         lnk->roce_pd = NULL;
 193 }
 194
 195 int smc_ib_create_protection_domain(struct smc_link *lnk)
 196 {
 197         int rc;
 198
 199         lnk->roce_pd = ib_alloc_pd(lnk->smcibdev->ibdev, 0);
 200         rc = PTR_ERR_OR_ZERO(lnk->roce_pd);
 201         if (IS_ERR(lnk->roce_pd))
 202                 lnk->roce_pd = NULL;
 203         return rc;
 204 }
 205
 206 static void smc_ib_qp_event_handler(struct ib_event *ibevent, void *priv)
 207 {
 208         switch (ibevent->event) {
 209         case IB_EVENT_DEVICE_FATAL:
 210         case IB_EVENT_GID_CHANGE:
 211         case IB_EVENT_PORT_ERR:
 212         case IB_EVENT_QP_ACCESS_ERR:
 213                 /* tbd in follow-on patch:
 214                  * abnormal close of corresponding connections
 215                  */
 216                 break;
 217         default:
 218                 break;
 219         }
 220 }
 221
 222 void smc_ib_destroy_queue_pair(struct smc_link *lnk)
 223 {
 224         ib_destroy_qp(lnk->roce_qp);
 225         lnk->roce_qp = NULL;
 226 }
 227
 228 /* create a queue pair within the protection domain for a link */
 229 int smc_ib_create_queue_pair(struct smc_link *lnk)
 230 {
 231         struct ib_qp_init_attr qp_attr = {
 232                 .event_handler = smc_ib_qp_event_handler,
 233                 .qp_context = lnk,
 234                 .send_cq = lnk->smcibdev->roce_cq_send,
 235                 .recv_cq = lnk->smcibdev->roce_cq_recv,
 236                 .srq = NULL,
 237                 .cap = {
 238                                 /* include unsolicited rdma_writes as well,
 239                                  * there are max. 2 RDMA_WRITE per 1 WR_SEND
 240                                  */
 241                         .max_send_wr = SMC_WR_BUF_CNT * 3,
 242                         .max_recv_wr = SMC_WR_BUF_CNT * 3,
 243                         .max_send_sge = SMC_IB_MAX_SEND_SGE,
 244                         .max_recv_sge = 1,
 245                 },
 246                 .sq_sig_type = IB_SIGNAL_REQ_WR,
 247                 .qp_type = IB_QPT_RC,
 248         };
 249         int rc;
 250
 251         lnk->roce_qp = ib_create_qp(lnk->roce_pd, &qp_attr);
 252         rc = PTR_ERR_OR_ZERO(lnk->roce_qp);
 253         if (IS_ERR(lnk->roce_qp))
 254                 lnk->roce_qp = NULL;
 255         else
 256                 smc_wr_remember_qp_attr(lnk);
 257         return rc;
 258 }
 259
 260 void smc_ib_put_memory_region(struct ib_mr *mr)
 261 {
 262         ib_dereg_mr(mr);
 263 }
 264
 265 static int smc_ib_map_mr_sg(struct smc_buf_desc *buf_slot)
 266 {
 267         unsigned int offset = 0;
 268         int sg_num;
 269
 270         /* map the largest prefix of a dma mapped SG list */
 271         sg_num = ib_map_mr_sg(buf_slot->mr_rx[SMC_SINGLE_LINK],
 272                               buf_slot->sgt[SMC_SINGLE_LINK].sgl,
 273                               buf_slot->sgt[SMC_SINGLE_LINK].orig_nents,
 274                               &offset, PAGE_SIZE);
 275
 276         return sg_num;
 277 }
 278
 279 /* Allocate a memory region and map the dma mapped SG list of buf_slot */
 280 int smc_ib_get_memory_region(struct ib_pd *pd, int access_flags,
 281                              struct smc_buf_desc *buf_slot)
 282 {
 283         if (buf_slot->mr_rx[SMC_SINGLE_LINK])
 284                 return 0; /* already done */
 285
 286         buf_slot->mr_rx[SMC_SINGLE_LINK] =
 287                 ib_alloc_mr(pd, IB_MR_TYPE_MEM_REG, 1 << buf_slot->order);
 288         if (IS_ERR(buf_slot->mr_rx[SMC_SINGLE_LINK])) {
 289                 int rc;
 290
 291                 rc = PTR_ERR(buf_slot->mr_rx[SMC_SINGLE_LINK]);
 292                 buf_slot->mr_rx[SMC_SINGLE_LINK] = NULL;
 293                 return rc;
 294         }
 295
 296         if (smc_ib_map_mr_sg(buf_slot) != 1)
 297                 return -EINVAL;
 298
 299         return 0;
 300 }
 301
 302 /* synchronize buffer usage for cpu access */
 303 void smc_ib_sync_sg_for_cpu(struct smc_ib_device *smcibdev,
 304                             struct smc_buf_desc *buf_slot,
 305                             enum dma_data_direction data_direction)
 306 {
 307         struct scatterlist *sg;
 308         unsigned int i;
 309
 310         /* for now there is just one DMA address */
 311         for_each_sg(buf_slot->sgt[SMC_SINGLE_LINK].sgl, sg,
 312                     buf_slot->sgt[SMC_SINGLE_LINK].nents, i) {
 313                 if (!sg_dma_len(sg))
 314                         break;
 315                 ib_dma_sync_single_for_cpu(smcibdev->ibdev,
 316                                            sg_dma_address(sg),
 317                                            sg_dma_len(sg),
 318                                            data_direction);
 319         }
 320 }
 321
 322 /* synchronize buffer usage for device access */
 323 void smc_ib_sync_sg_for_device(struct smc_ib_device *smcibdev,
 324                                struct smc_buf_desc *buf_slot,
 325                                enum dma_data_direction data_direction)
 326 {
 327         struct scatterlist *sg;
 328         unsigned int i;
 329
 330         /* for now there is just one DMA address */
 331         for_each_sg(buf_slot->sgt[SMC_SINGLE_LINK].sgl, sg,
 332                     buf_slot->sgt[SMC_SINGLE_LINK].nents, i) {
 333                 if (!sg_dma_len(sg))
 334                         break;
 335                 ib_dma_sync_single_for_device(smcibdev->ibdev,
 336                                               sg_dma_address(sg),
 337                                               sg_dma_len(sg),
 338                                               data_direction);
 339         }
 340 }
 341
 342 /* Map a new TX or RX buffer SG-table to DMA */
 343 int smc_ib_buf_map_sg(struct smc_ib_device *smcibdev,
 344                       struct smc_buf_desc *buf_slot,
 345                       enum dma_data_direction data_direction)
 346 {
 347         int mapped_nents;
 348
 349         mapped_nents = ib_dma_map_sg(smcibdev->ibdev,
 350                                      buf_slot->sgt[SMC_SINGLE_LINK].sgl,
 351                                      buf_slot->sgt[SMC_SINGLE_LINK].orig_nents,
 352                                      data_direction);
 353         if (!mapped_nents)
 354                 return -ENOMEM;
 355
 356         return mapped_nents;
 357 }
 358
 359 void smc_ib_buf_unmap_sg(struct smc_ib_device *smcibdev,
 360                          struct smc_buf_desc *buf_slot,
 361                          enum dma_data_direction data_direction)
 362 {
 363         if (!buf_slot->sgt[SMC_SINGLE_LINK].sgl->dma_address)
 364                 return; /* already unmapped */
 365
 366         ib_dma_unmap_sg(smcibdev->ibdev,
 367                         buf_slot->sgt[SMC_SINGLE_LINK].sgl,
 368                         buf_slot->sgt[SMC_SINGLE_LINK].orig_nents,
 369                         data_direction);
 370         buf_slot->sgt[SMC_SINGLE_LINK].sgl->dma_address = 0;
 371 }
 372
 373 static int smc_ib_fill_gid_and_mac(struct smc_ib_device *smcibdev, u8 ibport)
 374 {
 375         struct net_device *ndev;
 376         int rc;
 377
 378         rc = ib_query_gid(smcibdev->ibdev, ibport, 0,
 379                           &smcibdev->gid[ibport - 1], NULL);
 380         /* the SMC protocol requires specification of the roce MAC address;
 381          * if net_device cannot be determined, it can be derived from gid 0
 382          */
 383         ndev = smcibdev->ibdev->get_netdev(smcibdev->ibdev, ibport);
 384         if (ndev) {
 385                 memcpy(&smcibdev->mac, ndev->dev_addr, ETH_ALEN);
 386                 dev_put(ndev);
 387         } else if (!rc) {
 388                 memcpy(&smcibdev->mac[ibport - 1][0],
 389                        &smcibdev->gid[ibport - 1].raw[8], 3);
 390                 memcpy(&smcibdev->mac[ibport - 1][3],
 391                        &smcibdev->gid[ibport - 1].raw[13], 3);
 392                 smcibdev->mac[ibport - 1][0] &= ~0x02;
 393         }
 394         return rc;
 395 }
 396
 397 /* Create an identifier unique for this instance of SMC-R.
 398  * The MAC-address of the first active registered IB device
 399  * plus a random 2-byte number is used to create this identifier.
 400  * This name is delivered to the peer during connection initialization.
 401  */
 402 static inline void smc_ib_define_local_systemid(struct smc_ib_device *smcibdev,
 403                                                 u8 ibport)
 404 {
 405         memcpy(&local_systemid[2], &smcibdev->mac[ibport - 1],
 406                sizeof(smcibdev->mac[ibport - 1]));
 407         get_random_bytes(&local_systemid[0], 2);
 408 }
 409
 410 bool smc_ib_port_active(struct smc_ib_device *smcibdev, u8 ibport)
 411 {
 412         return smcibdev->pattr[ibport - 1].state == IB_PORT_ACTIVE;
 413 }
 414
 415 int smc_ib_remember_port_attr(struct smc_ib_device *smcibdev, u8 ibport)
 416 {
 417         int rc;
 418
 419         memset(&smcibdev->pattr[ibport - 1], 0,
 420                sizeof(smcibdev->pattr[ibport - 1]));
 421         rc = ib_query_port(smcibdev->ibdev, ibport,
 422                            &smcibdev->pattr[ibport - 1]);
 423         if (rc)
 424                 goto out;
 425         rc = smc_ib_fill_gid_and_mac(smcibdev, ibport);
 426         if (rc)
 427                 goto out;
 428         if (!strncmp(local_systemid, SMC_LOCAL_SYSTEMID_RESET,
 429                      sizeof(local_systemid)) &&
 430             smc_ib_port_active(smcibdev, ibport))
 431                 /* create unique system identifier */
 432                 smc_ib_define_local_systemid(smcibdev, ibport);
 433 out:
 434         return rc;
 435 }
 436
 437 long smc_ib_setup_per_ibdev(struct smc_ib_device *smcibdev)
 438 {
 439         struct ib_cq_init_attr cqattr = {
 440                 .cqe = SMC_MAX_CQE, .comp_vector = 0 };
 441         int cqe_size_order, smc_order;
 442         long rc;
 443
 444         /* the calculated number of cq entries fits to mlx5 cq allocation */
 445         cqe_size_order = cache_line_size() == 128 ? 7 : 6;
 446         smc_order = MAX_ORDER - cqe_size_order - 1;
 447         if (SMC_MAX_CQE + 2 > (0x00000001 << smc_order) * PAGE_SIZE)
 448                 cqattr.cqe = (0x00000001 << smc_order) * PAGE_SIZE - 2;
 449         smcibdev->roce_cq_send = ib_create_cq(smcibdev->ibdev,
 450                                               smc_wr_tx_cq_handler, NULL,
 451                                               smcibdev, &cqattr);
 452         rc = PTR_ERR_OR_ZERO(smcibdev->roce_cq_send);
 453         if (IS_ERR(smcibdev->roce_cq_send)) {
 454                 smcibdev->roce_cq_send = NULL;
 455                 return rc;
 456         }
 457         smcibdev->roce_cq_recv = ib_create_cq(smcibdev->ibdev,
 458                                               smc_wr_rx_cq_handler, NULL,
 459                                               smcibdev, &cqattr);
 460         rc = PTR_ERR_OR_ZERO(smcibdev->roce_cq_recv);
 461         if (IS_ERR(smcibdev->roce_cq_recv)) {
 462                 smcibdev->roce_cq_recv = NULL;
 463                 goto err;
 464         }
 465         INIT_IB_EVENT_HANDLER(&smcibdev->event_handler, smcibdev->ibdev,
 466                               smc_ib_global_event_handler);
 467         ib_register_event_handler(&smcibdev->event_handler);
 468         smc_wr_add_dev(smcibdev);
 469         smcibdev->initialized = 1;
 470         return rc;
 471
 472 err:
 473         ib_destroy_cq(smcibdev->roce_cq_send);
 474         return rc;
 475 }
 476
 477 static void smc_ib_cleanup_per_ibdev(struct smc_ib_device *smcibdev)
 478 {
 479         if (!smcibdev->initialized)
 480                 return;
 481         smc_wr_remove_dev(smcibdev);
 482         ib_unregister_event_handler(&smcibdev->event_handler);
 483         ib_destroy_cq(smcibdev->roce_cq_recv);
 484         ib_destroy_cq(smcibdev->roce_cq_send);
 485 }
 486
 487 static struct ib_client smc_ib_client;
 488
 489 /* callback function for ib_register_client() */
 490 static void smc_ib_add_dev(struct ib_device *ibdev)
 491 {
 492         struct smc_ib_device *smcibdev;
 493
 494         if (ibdev->node_type != RDMA_NODE_IB_CA)
 495                 return;
 496
 497         smcibdev = kzalloc(sizeof(*smcibdev), GFP_KERNEL);
 498         if (!smcibdev)
 499                 return;
 500
 501         smcibdev->ibdev = ibdev;
 502         INIT_WORK(&smcibdev->port_event_work, smc_ib_port_event_work);
 503
 504         spin_lock(&smc_ib_devices.lock);
 505         list_add_tail(&smcibdev->list, &smc_ib_devices.list);
 506         spin_unlock(&smc_ib_devices.lock);
 507         ib_set_client_data(ibdev, &smc_ib_client, smcibdev);
 508 }
 509
 510 /* callback function for ib_register_client() */
 511 static void smc_ib_remove_dev(struct ib_device *ibdev, void *client_data)
 512 {
 513         struct smc_ib_device *smcibdev;
 514
 515         smcibdev = ib_get_client_data(ibdev, &smc_ib_client);
 516         if (!smcibdev || smcibdev->ibdev != ibdev)
 517                 return;
 518         ib_set_client_data(ibdev, &smc_ib_client, NULL);
 519         spin_lock(&smc_ib_devices.lock);
 520         list_del_init(&smcibdev->list); /* remove from smc_ib_devices */
 521         spin_unlock(&smc_ib_devices.lock);
 522         smc_pnet_remove_by_ibdev(smcibdev);
 523         smc_ib_cleanup_per_ibdev(smcibdev);
 524         kfree(smcibdev);
 525 }
 526
 527 static struct ib_client smc_ib_client = {
 528         .name   = "smc_ib",
 529         .add    = smc_ib_add_dev,
 530         .remove = smc_ib_remove_dev,
 531 };
 532
 533 int __init smc_ib_register_client(void)
 534 {
 535         return ib_register_client(&smc_ib_client);
 536 }
 537
 538 void smc_ib_unregister_client(void)
 539 {
 540         ib_unregister_client(&smc_ib_client);
 541 }