net/smc/smc_ib.c

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