drivers/infiniband/ulp/rtrs/rtrs-clt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * RDMA Transport Layer
   4  *
   5  * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
   6  * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
   7  * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
   8  */
   9
  10 #undef pr_fmt
  11 #define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
  12
  13 #include <linux/module.h>
  14 #include <linux/rculist.h>
  15 #include <linux/random.h>
  16
  17 #include "rtrs-clt.h"
  18 #include "rtrs-log.h"
  19 #include "rtrs-clt-trace.h"
  20
  21 #define RTRS_CONNECT_TIMEOUT_MS 30000
  22 /*
  23  * Wait a bit before trying to reconnect after a failure
  24  * in order to give server time to finish clean up which
  25  * leads to "false positives" failed reconnect attempts
  26  */
  27 #define RTRS_RECONNECT_BACKOFF 1000
  28 /*
  29  * Wait for additional random time between 0 and 8 seconds
  30  * before starting to reconnect to avoid clients reconnecting
  31  * all at once in case of a major network outage
  32  */
  33 #define RTRS_RECONNECT_SEED 8
  34
  35 #define FIRST_CONN 0x01
  36 /* limit to 128 * 4k = 512k max IO */
  37 #define RTRS_MAX_SEGMENTS          128
  38
  39 MODULE_DESCRIPTION("RDMA Transport Client");
  40 MODULE_LICENSE("GPL");
  41
  42 static const struct rtrs_rdma_dev_pd_ops dev_pd_ops;
  43 static struct rtrs_rdma_dev_pd dev_pd = {
  44         .ops = &dev_pd_ops
  45 };
  46
  47 static struct workqueue_struct *rtrs_wq;
  48 static const struct class rtrs_clt_dev_class = {
  49         .name = "rtrs-client",
  50 };
  51
  52 static inline bool rtrs_clt_is_connected(const struct rtrs_clt_sess *clt)
  53 {
  54         struct rtrs_clt_path *clt_path;
  55         bool connected = false;
  56
  57         rcu_read_lock();
  58         list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry)
  59                 if (READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTED) {
  60                         connected = true;
  61                         break;
  62                 }
  63         rcu_read_unlock();
  64
  65         return connected;
  66 }
  67
  68 static struct rtrs_permit *
  69 __rtrs_get_permit(struct rtrs_clt_sess *clt, enum rtrs_clt_con_type con_type)
  70 {
  71         size_t max_depth = clt->queue_depth;
  72         struct rtrs_permit *permit;
  73         int bit;
  74
  75         /*
  76          * Adapted from null_blk get_tag(). Callers from different cpus may
  77          * grab the same bit, since find_first_zero_bit is not atomic.
  78          * But then the test_and_set_bit_lock will fail for all the
  79          * callers but one, so that they will loop again.
  80          * This way an explicit spinlock is not required.
  81          */
  82         do {
  83                 bit = find_first_zero_bit(clt->permits_map, max_depth);
  84                 if (bit >= max_depth)
  85                         return NULL;
  86         } while (test_and_set_bit_lock(bit, clt->permits_map));
  87
  88         permit = get_permit(clt, bit);
  89         WARN_ON(permit->mem_id != bit);
  90         permit->cpu_id = raw_smp_processor_id();
  91         permit->con_type = con_type;
  92
  93         return permit;
  94 }
  95
  96 static inline void __rtrs_put_permit(struct rtrs_clt_sess *clt,
  97                                       struct rtrs_permit *permit)
  98 {
  99         clear_bit_unlock(permit->mem_id, clt->permits_map);
 100 }
 101
 102 /**
 103  * rtrs_clt_get_permit() - allocates permit for future RDMA operation
 104  * @clt:        Current session
 105  * @con_type:   Type of connection to use with the permit
 106  * @can_wait:   Wait type
 107  *
 108  * Description:
 109  *    Allocates permit for the following RDMA operation.  Permit is used
 110  *    to preallocate all resources and to propagate memory pressure
 111  *    up earlier.
 112  *
 113  * Context:
 114  *    Can sleep if @wait == RTRS_PERMIT_WAIT
 115  */
 116 struct rtrs_permit *rtrs_clt_get_permit(struct rtrs_clt_sess *clt,
 117                                           enum rtrs_clt_con_type con_type,
 118                                           enum wait_type can_wait)
 119 {
 120         struct rtrs_permit *permit;
 121         DEFINE_WAIT(wait);
 122
 123         permit = __rtrs_get_permit(clt, con_type);
 124         if (permit || !can_wait)
 125                 return permit;
 126
 127         do {
 128                 prepare_to_wait(&clt->permits_wait, &wait,
 129                                 TASK_UNINTERRUPTIBLE);
 130                 permit = __rtrs_get_permit(clt, con_type);
 131                 if (permit)
 132                         break;
 133
 134                 io_schedule();
 135         } while (1);
 136
 137         finish_wait(&clt->permits_wait, &wait);
 138
 139         return permit;
 140 }
 141 EXPORT_SYMBOL(rtrs_clt_get_permit);
 142
 143 /**
 144  * rtrs_clt_put_permit() - puts allocated permit
 145  * @clt:        Current session
 146  * @permit:     Permit to be freed
 147  *
 148  * Context:
 149  *    Does not matter
 150  */
 151 void rtrs_clt_put_permit(struct rtrs_clt_sess *clt,
 152                          struct rtrs_permit *permit)
 153 {
 154         if (WARN_ON(!test_bit(permit->mem_id, clt->permits_map)))
 155                 return;
 156
 157         __rtrs_put_permit(clt, permit);
 158
 159         /*
 160          * rtrs_clt_get_permit() adds itself to the &clt->permits_wait list
 161          * before calling schedule(). So if rtrs_clt_get_permit() is sleeping
 162          * it must have added itself to &clt->permits_wait before
 163          * __rtrs_put_permit() finished.
 164          * Hence it is safe to guard wake_up() with a waitqueue_active() test.
 165          */
 166         if (waitqueue_active(&clt->permits_wait))
 167                 wake_up(&clt->permits_wait);
 168 }
 169 EXPORT_SYMBOL(rtrs_clt_put_permit);
 170
 171 /**
 172  * rtrs_permit_to_clt_con() - returns RDMA connection pointer by the permit
 173  * @clt_path: client path pointer
 174  * @permit: permit for the allocation of the RDMA buffer
 175  * Note:
 176  *     IO connection starts from 1.
 177  *     0 connection is for user messages.
 178  */
 179 static
 180 struct rtrs_clt_con *rtrs_permit_to_clt_con(struct rtrs_clt_path *clt_path,
 181                                             struct rtrs_permit *permit)
 182 {
 183         int id = 0;
 184
 185         if (permit->con_type == RTRS_IO_CON)
 186                 id = (permit->cpu_id % (clt_path->s.irq_con_num - 1)) + 1;
 187
 188         return to_clt_con(clt_path->s.con[id]);
 189 }
 190
 191 /**
 192  * rtrs_clt_change_state() - change the session state through session state
 193  * machine.
 194  *
 195  * @clt_path: client path to change the state of.
 196  * @new_state: state to change to.
 197  *
 198  * returns true if sess's state is changed to new state, otherwise return false.
 199  *
 200  * Locks:
 201  * state_wq lock must be hold.
 202  */
 203 static bool rtrs_clt_change_state(struct rtrs_clt_path *clt_path,
 204                                      enum rtrs_clt_state new_state)
 205 {
 206         enum rtrs_clt_state old_state;
 207         bool changed = false;
 208
 209         lockdep_assert_held(&clt_path->state_wq.lock);
 210
 211         old_state = clt_path->state;
 212         switch (new_state) {
 213         case RTRS_CLT_CONNECTING:
 214                 switch (old_state) {
 215                 case RTRS_CLT_RECONNECTING:
 216                         changed = true;
 217                         fallthrough;
 218                 default:
 219                         break;
 220                 }
 221                 break;
 222         case RTRS_CLT_RECONNECTING:
 223                 switch (old_state) {
 224                 case RTRS_CLT_CONNECTED:
 225                 case RTRS_CLT_CONNECTING_ERR:
 226                 case RTRS_CLT_CLOSED:
 227                         changed = true;
 228                         fallthrough;
 229                 default:
 230                         break;
 231                 }
 232                 break;
 233         case RTRS_CLT_CONNECTED:
 234                 switch (old_state) {
 235                 case RTRS_CLT_CONNECTING:
 236                         changed = true;
 237                         fallthrough;
 238                 default:
 239                         break;
 240                 }
 241                 break;
 242         case RTRS_CLT_CONNECTING_ERR:
 243                 switch (old_state) {
 244                 case RTRS_CLT_CONNECTING:
 245                         changed = true;
 246                         fallthrough;
 247                 default:
 248                         break;
 249                 }
 250                 break;
 251         case RTRS_CLT_CLOSING:
 252                 switch (old_state) {
 253                 case RTRS_CLT_CONNECTING:
 254                 case RTRS_CLT_CONNECTING_ERR:
 255                 case RTRS_CLT_RECONNECTING:
 256                 case RTRS_CLT_CONNECTED:
 257                         changed = true;
 258                         fallthrough;
 259                 default:
 260                         break;
 261                 }
 262                 break;
 263         case RTRS_CLT_CLOSED:
 264                 switch (old_state) {
 265                 case RTRS_CLT_CLOSING:
 266                         changed = true;
 267                         fallthrough;
 268                 default:
 269                         break;
 270                 }
 271                 break;
 272         case RTRS_CLT_DEAD:
 273                 switch (old_state) {
 274                 case RTRS_CLT_CLOSED:
 275                         changed = true;
 276                         fallthrough;
 277                 default:
 278                         break;
 279                 }
 280                 break;
 281         default:
 282                 break;
 283         }
 284         if (changed) {
 285                 clt_path->state = new_state;
 286                 wake_up_locked(&clt_path->state_wq);
 287         }
 288
 289         return changed;
 290 }
 291
 292 static bool rtrs_clt_change_state_from_to(struct rtrs_clt_path *clt_path,
 293                                            enum rtrs_clt_state old_state,
 294                                            enum rtrs_clt_state new_state)
 295 {
 296         bool changed = false;
 297
 298         spin_lock_irq(&clt_path->state_wq.lock);
 299         if (clt_path->state == old_state)
 300                 changed = rtrs_clt_change_state(clt_path, new_state);
 301         spin_unlock_irq(&clt_path->state_wq.lock);
 302
 303         return changed;
 304 }
 305
 306 static void rtrs_clt_stop_and_destroy_conns(struct rtrs_clt_path *clt_path);
 307 static void rtrs_rdma_error_recovery(struct rtrs_clt_con *con)
 308 {
 309         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
 310
 311         trace_rtrs_rdma_error_recovery(clt_path);
 312
 313         if (rtrs_clt_change_state_from_to(clt_path,
 314                                            RTRS_CLT_CONNECTED,
 315                                            RTRS_CLT_RECONNECTING)) {
 316                 queue_work(rtrs_wq, &clt_path->err_recovery_work);
 317         } else {
 318                 /*
 319                  * Error can happen just on establishing new connection,
 320                  * so notify waiter with error state, waiter is responsible
 321                  * for cleaning the rest and reconnect if needed.
 322                  */
 323                 rtrs_clt_change_state_from_to(clt_path,
 324                                                RTRS_CLT_CONNECTING,
 325                                                RTRS_CLT_CONNECTING_ERR);
 326         }
 327 }
 328
 329 static void rtrs_clt_fast_reg_done(struct ib_cq *cq, struct ib_wc *wc)
 330 {
 331         struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context);
 332
 333         if (wc->status != IB_WC_SUCCESS) {
 334                 rtrs_err(con->c.path, "Failed IB_WR_REG_MR: %s\n",
 335                           ib_wc_status_msg(wc->status));
 336                 rtrs_rdma_error_recovery(con);
 337         }
 338 }
 339
 340 static struct ib_cqe fast_reg_cqe = {
 341         .done = rtrs_clt_fast_reg_done
 342 };
 343
 344 static void complete_rdma_req(struct rtrs_clt_io_req *req, int errno,
 345                               bool notify, bool can_wait);
 346
 347 static void rtrs_clt_inv_rkey_done(struct ib_cq *cq, struct ib_wc *wc)
 348 {
 349         struct rtrs_clt_io_req *req =
 350                 container_of(wc->wr_cqe, typeof(*req), inv_cqe);
 351         struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context);
 352
 353         if (wc->status != IB_WC_SUCCESS) {
 354                 rtrs_err(con->c.path, "Failed IB_WR_LOCAL_INV: %s\n",
 355                           ib_wc_status_msg(wc->status));
 356                 rtrs_rdma_error_recovery(con);
 357         }
 358         req->need_inv = false;
 359         if (req->need_inv_comp)
 360                 complete(&req->inv_comp);
 361         else
 362                 /* Complete request from INV callback */
 363                 complete_rdma_req(req, req->inv_errno, true, false);
 364 }
 365
 366 static int rtrs_inv_rkey(struct rtrs_clt_io_req *req)
 367 {
 368         struct rtrs_clt_con *con = req->con;
 369         struct ib_send_wr wr = {
 370                 .opcode             = IB_WR_LOCAL_INV,
 371                 .wr_cqe             = &req->inv_cqe,
 372                 .send_flags         = IB_SEND_SIGNALED,
 373                 .ex.invalidate_rkey = req->mr->rkey,
 374         };
 375         req->inv_cqe.done = rtrs_clt_inv_rkey_done;
 376
 377         return ib_post_send(con->c.qp, &wr, NULL);
 378 }
 379
 380 static void complete_rdma_req(struct rtrs_clt_io_req *req, int errno,
 381                               bool notify, bool can_wait)
 382 {
 383         struct rtrs_clt_con *con = req->con;
 384         struct rtrs_clt_path *clt_path;
 385         int err;
 386
 387         if (WARN_ON(!req->in_use))
 388                 return;
 389         if (WARN_ON(!req->con))
 390                 return;
 391         clt_path = to_clt_path(con->c.path);
 392
 393         if (req->sg_cnt) {
 394                 if (req->dir == DMA_FROM_DEVICE && req->need_inv) {
 395                         /*
 396                          * We are here to invalidate read requests
 397                          * ourselves.  In normal scenario server should
 398                          * send INV for all read requests, but
 399                          * we are here, thus two things could happen:
 400                          *
 401                          *    1.  this is failover, when errno != 0
 402                          *        and can_wait == 1,
 403                          *
 404                          *    2.  something totally bad happened and
 405                          *        server forgot to send INV, so we
 406                          *        should do that ourselves.
 407                          */
 408
 409                         if (can_wait) {
 410                                 req->need_inv_comp = true;
 411                         } else {
 412                                 /* This should be IO path, so always notify */
 413                                 WARN_ON(!notify);
 414                                 /* Save errno for INV callback */
 415                                 req->inv_errno = errno;
 416                         }
 417
 418                         refcount_inc(&req->ref);
 419                         err = rtrs_inv_rkey(req);
 420                         if (err) {
 421                                 rtrs_err(con->c.path, "Send INV WR key=%#x: %d\n",
 422                                           req->mr->rkey, err);
 423                         } else if (can_wait) {
 424                                 wait_for_completion(&req->inv_comp);
 425                         } else {
 426                                 /*
 427                                  * Something went wrong, so request will be
 428                                  * completed from INV callback.
 429                                  */
 430                                 WARN_ON_ONCE(1);
 431
 432                                 return;
 433                         }
 434                         if (!refcount_dec_and_test(&req->ref))
 435                                 return;
 436                 }
 437                 ib_dma_unmap_sg(clt_path->s.dev->ib_dev, req->sglist,
 438                                 req->sg_cnt, req->dir);
 439         }
 440         if (!refcount_dec_and_test(&req->ref))
 441                 return;
 442         if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
 443                 atomic_dec(&clt_path->stats->inflight);
 444
 445         req->in_use = false;
 446         req->con = NULL;
 447
 448         if (errno) {
 449                 rtrs_err_rl(con->c.path, "IO request failed: error=%d path=%s [%s:%u] notify=%d\n",
 450                             errno, kobject_name(&clt_path->kobj), clt_path->hca_name,
 451                             clt_path->hca_port, notify);
 452         }
 453
 454         if (notify)
 455                 req->conf(req->priv, errno);
 456 }
 457
 458 static int rtrs_post_send_rdma(struct rtrs_clt_con *con,
 459                                 struct rtrs_clt_io_req *req,
 460                                 struct rtrs_rbuf *rbuf, u32 off,
 461                                 u32 imm, struct ib_send_wr *wr)
 462 {
 463         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
 464         enum ib_send_flags flags;
 465         struct ib_sge sge;
 466
 467         if (!req->sg_size) {
 468                 rtrs_wrn(con->c.path,
 469                          "Doing RDMA Write failed, no data supplied\n");
 470                 return -EINVAL;
 471         }
 472
 473         /* user data and user message in the first list element */
 474         sge.addr   = req->iu->dma_addr;
 475         sge.length = req->sg_size;
 476         sge.lkey   = clt_path->s.dev->ib_pd->local_dma_lkey;
 477
 478         /*
 479          * From time to time we have to post signalled sends,
 480          * or send queue will fill up and only QP reset can help.
 481          */
 482         flags = atomic_inc_return(&con->c.wr_cnt) % clt_path->s.signal_interval ?
 483                         0 : IB_SEND_SIGNALED;
 484
 485         ib_dma_sync_single_for_device(clt_path->s.dev->ib_dev,
 486                                       req->iu->dma_addr,
 487                                       req->sg_size, DMA_TO_DEVICE);
 488
 489         return rtrs_iu_post_rdma_write_imm(&con->c, req->iu, &sge, 1,
 490                                             rbuf->rkey, rbuf->addr + off,
 491                                             imm, flags, wr, NULL);
 492 }
 493
 494 static void process_io_rsp(struct rtrs_clt_path *clt_path, u32 msg_id,
 495                            s16 errno, bool w_inval)
 496 {
 497         struct rtrs_clt_io_req *req;
 498
 499         if (WARN_ON(msg_id >= clt_path->queue_depth))
 500                 return;
 501
 502         req = &clt_path->reqs[msg_id];
 503         /* Drop need_inv if server responded with send with invalidation */
 504         req->need_inv &= !w_inval;
 505         complete_rdma_req(req, errno, true, false);
 506 }
 507
 508 static void rtrs_clt_recv_done(struct rtrs_clt_con *con, struct ib_wc *wc)
 509 {
 510         struct rtrs_iu *iu;
 511         int err;
 512         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
 513
 514         WARN_ON((clt_path->flags & RTRS_MSG_NEW_RKEY_F) == 0);
 515         iu = container_of(wc->wr_cqe, struct rtrs_iu,
 516                           cqe);
 517         err = rtrs_iu_post_recv(&con->c, iu);
 518         if (err) {
 519                 rtrs_err(con->c.path, "post iu failed %d\n", err);
 520                 rtrs_rdma_error_recovery(con);
 521         }
 522 }
 523
 524 static void rtrs_clt_rkey_rsp_done(struct rtrs_clt_con *con, struct ib_wc *wc)
 525 {
 526         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
 527         struct rtrs_msg_rkey_rsp *msg;
 528         u32 imm_type, imm_payload;
 529         bool w_inval = false;
 530         struct rtrs_iu *iu;
 531         u32 buf_id;
 532         int err;
 533
 534         WARN_ON((clt_path->flags & RTRS_MSG_NEW_RKEY_F) == 0);
 535
 536         iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
 537
 538         if (wc->byte_len < sizeof(*msg)) {
 539                 rtrs_err(con->c.path, "rkey response is malformed: size %d\n",
 540                           wc->byte_len);
 541                 goto out;
 542         }
 543         ib_dma_sync_single_for_cpu(clt_path->s.dev->ib_dev, iu->dma_addr,
 544                                    iu->size, DMA_FROM_DEVICE);
 545         msg = iu->buf;
 546         if (le16_to_cpu(msg->type) != RTRS_MSG_RKEY_RSP) {
 547                 rtrs_err(clt_path->clt,
 548                           "rkey response is malformed: type %d\n",
 549                           le16_to_cpu(msg->type));
 550                 goto out;
 551         }
 552         buf_id = le16_to_cpu(msg->buf_id);
 553         if (WARN_ON(buf_id >= clt_path->queue_depth))
 554                 goto out;
 555
 556         rtrs_from_imm(be32_to_cpu(wc->ex.imm_data), &imm_type, &imm_payload);
 557         if (imm_type == RTRS_IO_RSP_IMM ||
 558             imm_type == RTRS_IO_RSP_W_INV_IMM) {
 559                 u32 msg_id;
 560
 561                 w_inval = (imm_type == RTRS_IO_RSP_W_INV_IMM);
 562                 rtrs_from_io_rsp_imm(imm_payload, &msg_id, &err);
 563
 564                 if (WARN_ON(buf_id != msg_id))
 565                         goto out;
 566                 clt_path->rbufs[buf_id].rkey = le32_to_cpu(msg->rkey);
 567                 process_io_rsp(clt_path, msg_id, err, w_inval);
 568         }
 569         ib_dma_sync_single_for_device(clt_path->s.dev->ib_dev, iu->dma_addr,
 570                                       iu->size, DMA_FROM_DEVICE);
 571         return rtrs_clt_recv_done(con, wc);
 572 out:
 573         rtrs_rdma_error_recovery(con);
 574 }
 575
 576 static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc);
 577
 578 static struct ib_cqe io_comp_cqe = {
 579         .done = rtrs_clt_rdma_done
 580 };
 581
 582 /*
 583  * Post x2 empty WRs: first is for this RDMA with IMM,
 584  * second is for RECV with INV, which happened earlier.
 585  */
 586 static int rtrs_post_recv_empty_x2(struct rtrs_con *con, struct ib_cqe *cqe)
 587 {
 588         struct ib_recv_wr wr_arr[2], *wr;
 589         int i;
 590
 591         memset(wr_arr, 0, sizeof(wr_arr));
 592         for (i = 0; i < ARRAY_SIZE(wr_arr); i++) {
 593                 wr = &wr_arr[i];
 594                 wr->wr_cqe  = cqe;
 595                 if (i)
 596                         /* Chain backwards */
 597                         wr->next = &wr_arr[i - 1];
 598         }
 599
 600         return ib_post_recv(con->qp, wr, NULL);
 601 }
 602
 603 static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc)
 604 {
 605         struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context);
 606         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
 607         u32 imm_type, imm_payload;
 608         bool w_inval = false;
 609         int err;
 610
 611         if (wc->status != IB_WC_SUCCESS) {
 612                 if (wc->status != IB_WC_WR_FLUSH_ERR) {
 613                         rtrs_err(clt_path->clt, "RDMA failed: %s\n",
 614                                   ib_wc_status_msg(wc->status));
 615                         rtrs_rdma_error_recovery(con);
 616                 }
 617                 return;
 618         }
 619         rtrs_clt_update_wc_stats(con);
 620
 621         switch (wc->opcode) {
 622         case IB_WC_RECV_RDMA_WITH_IMM:
 623                 /*
 624                  * post_recv() RDMA write completions of IO reqs (read/write)
 625                  * and hb
 626                  */
 627                 if (WARN_ON(wc->wr_cqe->done != rtrs_clt_rdma_done))
 628                         return;
 629                 rtrs_from_imm(be32_to_cpu(wc->ex.imm_data),
 630                                &imm_type, &imm_payload);
 631                 if (imm_type == RTRS_IO_RSP_IMM ||
 632                     imm_type == RTRS_IO_RSP_W_INV_IMM) {
 633                         u32 msg_id;
 634
 635                         w_inval = (imm_type == RTRS_IO_RSP_W_INV_IMM);
 636                         rtrs_from_io_rsp_imm(imm_payload, &msg_id, &err);
 637
 638                         process_io_rsp(clt_path, msg_id, err, w_inval);
 639                 } else if (imm_type == RTRS_HB_MSG_IMM) {
 640                         WARN_ON(con->c.cid);
 641                         rtrs_send_hb_ack(&clt_path->s);
 642                         if (clt_path->flags & RTRS_MSG_NEW_RKEY_F)
 643                                 return  rtrs_clt_recv_done(con, wc);
 644                 } else if (imm_type == RTRS_HB_ACK_IMM) {
 645                         WARN_ON(con->c.cid);
 646                         clt_path->s.hb_missed_cnt = 0;
 647                         clt_path->s.hb_cur_latency =
 648                                 ktime_sub(ktime_get(), clt_path->s.hb_last_sent);
 649                         if (clt_path->flags & RTRS_MSG_NEW_RKEY_F)
 650                                 return  rtrs_clt_recv_done(con, wc);
 651                 } else {
 652                         rtrs_wrn(con->c.path, "Unknown IMM type %u\n",
 653                                   imm_type);
 654                 }
 655                 if (w_inval)
 656                         /*
 657                          * Post x2 empty WRs: first is for this RDMA with IMM,
 658                          * second is for RECV with INV, which happened earlier.
 659                          */
 660                         err = rtrs_post_recv_empty_x2(&con->c, &io_comp_cqe);
 661                 else
 662                         err = rtrs_post_recv_empty(&con->c, &io_comp_cqe);
 663                 if (err) {
 664                         rtrs_err(con->c.path, "rtrs_post_recv_empty(): %d\n",
 665                                   err);
 666                         rtrs_rdma_error_recovery(con);
 667                 }
 668                 break;
 669         case IB_WC_RECV:
 670                 /*
 671                  * Key invalidations from server side
 672                  */
 673                 WARN_ON(!(wc->wc_flags & IB_WC_WITH_INVALIDATE ||
 674                           wc->wc_flags & IB_WC_WITH_IMM));
 675                 WARN_ON(wc->wr_cqe->done != rtrs_clt_rdma_done);
 676                 if (clt_path->flags & RTRS_MSG_NEW_RKEY_F) {
 677                         if (wc->wc_flags & IB_WC_WITH_INVALIDATE)
 678                                 return  rtrs_clt_recv_done(con, wc);
 679
 680                         return  rtrs_clt_rkey_rsp_done(con, wc);
 681                 }
 682                 break;
 683         case IB_WC_RDMA_WRITE:
 684                 /*
 685                  * post_send() RDMA write completions of IO reqs (read/write)
 686                  * and hb.
 687                  */
 688                 break;
 689
 690         default:
 691                 rtrs_wrn(clt_path->clt, "Unexpected WC type: %d\n", wc->opcode);
 692                 return;
 693         }
 694 }
 695
 696 static int post_recv_io(struct rtrs_clt_con *con, size_t q_size)
 697 {
 698         int err, i;
 699         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
 700
 701         for (i = 0; i < q_size; i++) {
 702                 if (clt_path->flags & RTRS_MSG_NEW_RKEY_F) {
 703                         struct rtrs_iu *iu = &con->rsp_ius[i];
 704
 705                         err = rtrs_iu_post_recv(&con->c, iu);
 706                 } else {
 707                         err = rtrs_post_recv_empty(&con->c, &io_comp_cqe);
 708                 }
 709                 if (err)
 710                         return err;
 711         }
 712
 713         return 0;
 714 }
 715
 716 static int post_recv_path(struct rtrs_clt_path *clt_path)
 717 {
 718         size_t q_size = 0;
 719         int err, cid;
 720
 721         for (cid = 0; cid < clt_path->s.con_num; cid++) {
 722                 if (cid == 0)
 723                         q_size = SERVICE_CON_QUEUE_DEPTH;
 724                 else
 725                         q_size = clt_path->queue_depth;
 726
 727                 /*
 728                  * x2 for RDMA read responses + FR key invalidations,
 729                  * RDMA writes do not require any FR registrations.
 730                  */
 731                 q_size *= 2;
 732
 733                 err = post_recv_io(to_clt_con(clt_path->s.con[cid]), q_size);
 734                 if (err) {
 735                         rtrs_err(clt_path->clt, "post_recv_io(), err: %d\n",
 736                                  err);
 737                         return err;
 738                 }
 739         }
 740
 741         return 0;
 742 }
 743
 744 struct path_it {
 745         int i;
 746         struct list_head skip_list;
 747         struct rtrs_clt_sess *clt;
 748         struct rtrs_clt_path *(*next_path)(struct path_it *it);
 749 };
 750
 751 /*
 752  * rtrs_clt_get_next_path_or_null - get clt path from the list or return NULL
 753  * @head:       the head for the list.
 754  * @clt_path:   The element to take the next clt_path from.
 755  *
 756  * Next clt path returned in round-robin fashion, i.e. head will be skipped,
 757  * but if list is observed as empty, NULL will be returned.
 758  *
 759  * This function may safely run concurrently with the _rcu list-mutation
 760  * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
 761  */
 762 static inline struct rtrs_clt_path *
 763 rtrs_clt_get_next_path_or_null(struct list_head *head, struct rtrs_clt_path *clt_path)
 764 {
 765         return list_next_or_null_rcu(head, &clt_path->s.entry, typeof(*clt_path), s.entry) ?:
 766                                      list_next_or_null_rcu(head,
 767                                                            READ_ONCE((&clt_path->s.entry)->next),
 768                                                            typeof(*clt_path), s.entry);
 769 }
 770
 771 /**
 772  * get_next_path_rr() - Returns path in round-robin fashion.
 773  * @it: the path pointer
 774  *
 775  * Related to @MP_POLICY_RR
 776  *
 777  * Locks:
 778  *    rcu_read_lock() must be hold.
 779  */
 780 static struct rtrs_clt_path *get_next_path_rr(struct path_it *it)
 781 {
 782         struct rtrs_clt_path __rcu **ppcpu_path;
 783         struct rtrs_clt_path *path;
 784         struct rtrs_clt_sess *clt;
 785
 786         clt = it->clt;
 787
 788         /*
 789          * Here we use two RCU objects: @paths_list and @pcpu_path
 790          * pointer.  See rtrs_clt_remove_path_from_arr() for details
 791          * how that is handled.
 792          */
 793
 794         ppcpu_path = this_cpu_ptr(clt->pcpu_path);
 795         path = rcu_dereference(*ppcpu_path);
 796         if (!path)
 797                 path = list_first_or_null_rcu(&clt->paths_list,
 798                                               typeof(*path), s.entry);
 799         else
 800                 path = rtrs_clt_get_next_path_or_null(&clt->paths_list, path);
 801
 802         rcu_assign_pointer(*ppcpu_path, path);
 803
 804         return path;
 805 }
 806
 807 /**
 808  * get_next_path_min_inflight() - Returns path with minimal inflight count.
 809  * @it: the path pointer
 810  *
 811  * Related to @MP_POLICY_MIN_INFLIGHT
 812  *
 813  * Locks:
 814  *    rcu_read_lock() must be hold.
 815  */
 816 static struct rtrs_clt_path *get_next_path_min_inflight(struct path_it *it)
 817 {
 818         struct rtrs_clt_path *min_path = NULL;
 819         struct rtrs_clt_sess *clt = it->clt;
 820         struct rtrs_clt_path *clt_path;
 821         int min_inflight = INT_MAX;
 822         int inflight;
 823
 824         list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) {
 825                 if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
 826                         continue;
 827
 828                 if (!list_empty(raw_cpu_ptr(clt_path->mp_skip_entry)))
 829                         continue;
 830
 831                 inflight = atomic_read(&clt_path->stats->inflight);
 832
 833                 if (inflight < min_inflight) {
 834                         min_inflight = inflight;
 835                         min_path = clt_path;
 836                 }
 837         }
 838
 839         /*
 840          * add the path to the skip list, so that next time we can get
 841          * a different one
 842          */
 843         if (min_path)
 844                 list_add(raw_cpu_ptr(min_path->mp_skip_entry), &it->skip_list);
 845
 846         return min_path;
 847 }
 848
 849 /**
 850  * get_next_path_min_latency() - Returns path with minimal latency.
 851  * @it: the path pointer
 852  *
 853  * Return: a path with the lowest latency or NULL if all paths are tried
 854  *
 855  * Locks:
 856  *    rcu_read_lock() must be hold.
 857  *
 858  * Related to @MP_POLICY_MIN_LATENCY
 859  *
 860  * This DOES skip an already-tried path.
 861  * There is a skip-list to skip a path if the path has tried but failed.
 862  * It will try the minimum latency path and then the second minimum latency
 863  * path and so on. Finally it will return NULL if all paths are tried.
 864  * Therefore the caller MUST check the returned
 865  * path is NULL and trigger the IO error.
 866  */
 867 static struct rtrs_clt_path *get_next_path_min_latency(struct path_it *it)
 868 {
 869         struct rtrs_clt_path *min_path = NULL;
 870         struct rtrs_clt_sess *clt = it->clt;
 871         struct rtrs_clt_path *clt_path;
 872         ktime_t min_latency = KTIME_MAX;
 873         ktime_t latency;
 874
 875         list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) {
 876                 if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
 877                         continue;
 878
 879                 if (!list_empty(raw_cpu_ptr(clt_path->mp_skip_entry)))
 880                         continue;
 881
 882                 latency = clt_path->s.hb_cur_latency;
 883
 884                 if (latency < min_latency) {
 885                         min_latency = latency;
 886                         min_path = clt_path;
 887                 }
 888         }
 889
 890         /*
 891          * add the path to the skip list, so that next time we can get
 892          * a different one
 893          */
 894         if (min_path)
 895                 list_add(raw_cpu_ptr(min_path->mp_skip_entry), &it->skip_list);
 896
 897         return min_path;
 898 }
 899
 900 static inline void path_it_init(struct path_it *it, struct rtrs_clt_sess *clt)
 901 {
 902         INIT_LIST_HEAD(&it->skip_list);
 903         it->clt = clt;
 904         it->i = 0;
 905
 906         if (clt->mp_policy == MP_POLICY_RR)
 907                 it->next_path = get_next_path_rr;
 908         else if (clt->mp_policy == MP_POLICY_MIN_INFLIGHT)
 909                 it->next_path = get_next_path_min_inflight;
 910         else
 911                 it->next_path = get_next_path_min_latency;
 912 }
 913
 914 static inline void path_it_deinit(struct path_it *it)
 915 {
 916         struct list_head *skip, *tmp;
 917         /*
 918          * The skip_list is used only for the MIN_INFLIGHT and MIN_LATENCY policies.
 919          * We need to remove paths from it, so that next IO can insert
 920          * paths (->mp_skip_entry) into a skip_list again.
 921          */
 922         list_for_each_safe(skip, tmp, &it->skip_list)
 923                 list_del_init(skip);
 924 }
 925
 926 /**
 927  * rtrs_clt_init_req() - Initialize an rtrs_clt_io_req holding information
 928  * about an inflight IO.
 929  * The user buffer holding user control message (not data) is copied into
 930  * the corresponding buffer of rtrs_iu (req->iu->buf), which later on will
 931  * also hold the control message of rtrs.
 932  * @req: an io request holding information about IO.
 933  * @clt_path: client path
 934  * @conf: conformation callback function to notify upper layer.
 935  * @permit: permit for allocation of RDMA remote buffer
 936  * @priv: private pointer
 937  * @vec: kernel vector containing control message
 938  * @usr_len: length of the user message
 939  * @sg: scater list for IO data
 940  * @sg_cnt: number of scater list entries
 941  * @data_len: length of the IO data
 942  * @dir: direction of the IO.
 943  */
 944 static void rtrs_clt_init_req(struct rtrs_clt_io_req *req,
 945                               struct rtrs_clt_path *clt_path,
 946                               void (*conf)(void *priv, int errno),
 947                               struct rtrs_permit *permit, void *priv,
 948                               const struct kvec *vec, size_t usr_len,
 949                               struct scatterlist *sg, size_t sg_cnt,
 950                               size_t data_len, int dir)
 951 {
 952         struct iov_iter iter;
 953         size_t len;
 954
 955         req->permit = permit;
 956         req->in_use = true;
 957         req->usr_len = usr_len;
 958         req->data_len = data_len;
 959         req->sglist = sg;
 960         req->sg_cnt = sg_cnt;
 961         req->priv = priv;
 962         req->dir = dir;
 963         req->con = rtrs_permit_to_clt_con(clt_path, permit);
 964         req->conf = conf;
 965         req->need_inv = false;
 966         req->need_inv_comp = false;
 967         req->inv_errno = 0;
 968         refcount_set(&req->ref, 1);
 969         req->mp_policy = clt_path->clt->mp_policy;
 970
 971         iov_iter_kvec(&iter, ITER_SOURCE, vec, 1, usr_len);
 972         len = _copy_from_iter(req->iu->buf, usr_len, &iter);
 973         WARN_ON(len != usr_len);
 974
 975         reinit_completion(&req->inv_comp);
 976 }
 977
 978 static struct rtrs_clt_io_req *
 979 rtrs_clt_get_req(struct rtrs_clt_path *clt_path,
 980                  void (*conf)(void *priv, int errno),
 981                  struct rtrs_permit *permit, void *priv,
 982                  const struct kvec *vec, size_t usr_len,
 983                  struct scatterlist *sg, size_t sg_cnt,
 984                  size_t data_len, int dir)
 985 {
 986         struct rtrs_clt_io_req *req;
 987
 988         req = &clt_path->reqs[permit->mem_id];
 989         rtrs_clt_init_req(req, clt_path, conf, permit, priv, vec, usr_len,
 990                            sg, sg_cnt, data_len, dir);
 991         return req;
 992 }
 993
 994 static struct rtrs_clt_io_req *
 995 rtrs_clt_get_copy_req(struct rtrs_clt_path *alive_path,
 996                        struct rtrs_clt_io_req *fail_req)
 997 {
 998         struct rtrs_clt_io_req *req;
 999         struct kvec vec = {
1000                 .iov_base = fail_req->iu->buf,
1001                 .iov_len  = fail_req->usr_len
1002         };
1003
1004         req = &alive_path->reqs[fail_req->permit->mem_id];
1005         rtrs_clt_init_req(req, alive_path, fail_req->conf, fail_req->permit,
1006                            fail_req->priv, &vec, fail_req->usr_len,
1007                            fail_req->sglist, fail_req->sg_cnt,
1008                            fail_req->data_len, fail_req->dir);
1009         return req;
1010 }
1011
1012 static int rtrs_post_rdma_write_sg(struct rtrs_clt_con *con,
1013                                    struct rtrs_clt_io_req *req,
1014                                    struct rtrs_rbuf *rbuf, bool fr_en,
1015                                    u32 count, u32 size, u32 imm,
1016                                    struct ib_send_wr *wr,
1017                                    struct ib_send_wr *tail)
1018 {
1019         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1020         struct ib_sge *sge = req->sge;
1021         enum ib_send_flags flags;
1022         struct scatterlist *sg;
1023         size_t num_sge;
1024         int i;
1025         struct ib_send_wr *ptail = NULL;
1026
1027         if (fr_en) {
1028                 i = 0;
1029                 sge[i].addr   = req->mr->iova;
1030                 sge[i].length = req->mr->length;
1031                 sge[i].lkey   = req->mr->lkey;
1032                 i++;
1033                 num_sge = 2;
1034                 ptail = tail;
1035         } else {
1036                 for_each_sg(req->sglist, sg, count, i) {
1037                         sge[i].addr   = sg_dma_address(sg);
1038                         sge[i].length = sg_dma_len(sg);
1039                         sge[i].lkey   = clt_path->s.dev->ib_pd->local_dma_lkey;
1040                 }
1041                 num_sge = 1 + count;
1042         }
1043         sge[i].addr   = req->iu->dma_addr;
1044         sge[i].length = size;
1045         sge[i].lkey   = clt_path->s.dev->ib_pd->local_dma_lkey;
1046
1047         /*
1048          * From time to time we have to post signalled sends,
1049          * or send queue will fill up and only QP reset can help.
1050          */
1051         flags = atomic_inc_return(&con->c.wr_cnt) % clt_path->s.signal_interval ?
1052                         0 : IB_SEND_SIGNALED;
1053
1054         ib_dma_sync_single_for_device(clt_path->s.dev->ib_dev,
1055                                       req->iu->dma_addr,
1056                                       size, DMA_TO_DEVICE);
1057
1058         return rtrs_iu_post_rdma_write_imm(&con->c, req->iu, sge, num_sge,
1059                                             rbuf->rkey, rbuf->addr, imm,
1060                                             flags, wr, ptail);
1061 }
1062
1063 static int rtrs_map_sg_fr(struct rtrs_clt_io_req *req, size_t count)
1064 {
1065         int nr;
1066
1067         /* Align the MR to a 4K page size to match the block virt boundary */
1068         nr = ib_map_mr_sg(req->mr, req->sglist, count, NULL, SZ_4K);
1069         if (nr != count)
1070                 return nr < 0 ? nr : -EINVAL;
1071         ib_update_fast_reg_key(req->mr, ib_inc_rkey(req->mr->rkey));
1072
1073         return nr;
1074 }
1075
1076 static int rtrs_clt_write_req(struct rtrs_clt_io_req *req)
1077 {
1078         struct rtrs_clt_con *con = req->con;
1079         struct rtrs_path *s = con->c.path;
1080         struct rtrs_clt_path *clt_path = to_clt_path(s);
1081         struct rtrs_msg_rdma_write *msg;
1082
1083         struct rtrs_rbuf *rbuf;
1084         int ret, count = 0;
1085         u32 imm, buf_id;
1086         struct ib_reg_wr rwr;
1087         struct ib_send_wr inv_wr;
1088         struct ib_send_wr *wr = NULL;
1089         bool fr_en = false;
1090
1091         const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len;
1092
1093         if (tsize > clt_path->chunk_size) {
1094                 rtrs_wrn(s, "Write request failed, size too big %zu > %d\n",
1095                           tsize, clt_path->chunk_size);
1096                 return -EMSGSIZE;
1097         }
1098         if (req->sg_cnt) {
1099                 count = ib_dma_map_sg(clt_path->s.dev->ib_dev, req->sglist,
1100                                       req->sg_cnt, req->dir);
1101                 if (!count) {
1102                         rtrs_wrn(s, "Write request failed, map failed\n");
1103                         return -EINVAL;
1104                 }
1105         }
1106         /* put rtrs msg after sg and user message */
1107         msg = req->iu->buf + req->usr_len;
1108         msg->type = cpu_to_le16(RTRS_MSG_WRITE);
1109         msg->usr_len = cpu_to_le16(req->usr_len);
1110
1111         /* rtrs message on server side will be after user data and message */
1112         imm = req->permit->mem_off + req->data_len + req->usr_len;
1113         imm = rtrs_to_io_req_imm(imm);
1114         buf_id = req->permit->mem_id;
1115         req->sg_size = tsize;
1116         rbuf = &clt_path->rbufs[buf_id];
1117
1118         if (count) {
1119                 ret = rtrs_map_sg_fr(req, count);
1120                 if (ret < 0) {
1121                         rtrs_err_rl(s,
1122                                     "Write request failed, failed to map fast reg. data, err: %d\n",
1123                                     ret);
1124                         ib_dma_unmap_sg(clt_path->s.dev->ib_dev, req->sglist,
1125                                         req->sg_cnt, req->dir);
1126                         return ret;
1127                 }
1128                 inv_wr = (struct ib_send_wr) {
1129                         .opcode             = IB_WR_LOCAL_INV,
1130                         .wr_cqe             = &req->inv_cqe,
1131                         .send_flags         = IB_SEND_SIGNALED,
1132                         .ex.invalidate_rkey = req->mr->rkey,
1133                 };
1134                 req->inv_cqe.done = rtrs_clt_inv_rkey_done;
1135                 rwr = (struct ib_reg_wr) {
1136                         .wr.opcode = IB_WR_REG_MR,
1137                         .wr.wr_cqe = &fast_reg_cqe,
1138                         .mr = req->mr,
1139                         .key = req->mr->rkey,
1140                         .access = (IB_ACCESS_LOCAL_WRITE),
1141                 };
1142                 wr = &rwr.wr;
1143                 fr_en = true;
1144                 refcount_inc(&req->ref);
1145         }
1146         /*
1147          * Update stats now, after request is successfully sent it is not
1148          * safe anymore to touch it.
1149          */
1150         rtrs_clt_update_all_stats(req, WRITE);
1151
1152         ret = rtrs_post_rdma_write_sg(req->con, req, rbuf, fr_en, count,
1153                                       req->usr_len + sizeof(*msg),
1154                                       imm, wr, &inv_wr);
1155         if (ret) {
1156                 rtrs_err_rl(s,
1157                             "Write request failed: error=%d path=%s [%s:%u]\n",
1158                             ret, kobject_name(&clt_path->kobj), clt_path->hca_name,
1159                             clt_path->hca_port);
1160                 if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
1161                         atomic_dec(&clt_path->stats->inflight);
1162                 if (req->sg_cnt)
1163                         ib_dma_unmap_sg(clt_path->s.dev->ib_dev, req->sglist,
1164                                         req->sg_cnt, req->dir);
1165         }
1166
1167         return ret;
1168 }
1169
1170 static int rtrs_clt_read_req(struct rtrs_clt_io_req *req)
1171 {
1172         struct rtrs_clt_con *con = req->con;
1173         struct rtrs_path *s = con->c.path;
1174         struct rtrs_clt_path *clt_path = to_clt_path(s);
1175         struct rtrs_msg_rdma_read *msg;
1176         struct rtrs_ib_dev *dev = clt_path->s.dev;
1177
1178         struct ib_reg_wr rwr;
1179         struct ib_send_wr *wr = NULL;
1180
1181         int ret, count = 0;
1182         u32 imm, buf_id;
1183
1184         const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len;
1185
1186         if (tsize > clt_path->chunk_size) {
1187                 rtrs_wrn(s,
1188                           "Read request failed, message size is %zu, bigger than CHUNK_SIZE %d\n",
1189                           tsize, clt_path->chunk_size);
1190                 return -EMSGSIZE;
1191         }
1192
1193         if (req->sg_cnt) {
1194                 count = ib_dma_map_sg(dev->ib_dev, req->sglist, req->sg_cnt,
1195                                       req->dir);
1196                 if (!count) {
1197                         rtrs_wrn(s,
1198                                   "Read request failed, dma map failed\n");
1199                         return -EINVAL;
1200                 }
1201         }
1202         /* put our message into req->buf after user message*/
1203         msg = req->iu->buf + req->usr_len;
1204         msg->type = cpu_to_le16(RTRS_MSG_READ);
1205         msg->usr_len = cpu_to_le16(req->usr_len);
1206
1207         if (count) {
1208                 ret = rtrs_map_sg_fr(req, count);
1209                 if (ret < 0) {
1210                         rtrs_err_rl(s,
1211                                      "Read request failed, failed to map  fast reg. data, err: %d\n",
1212                                      ret);
1213                         ib_dma_unmap_sg(dev->ib_dev, req->sglist, req->sg_cnt,
1214                                         req->dir);
1215                         return ret;
1216                 }
1217                 rwr = (struct ib_reg_wr) {
1218                         .wr.opcode = IB_WR_REG_MR,
1219                         .wr.wr_cqe = &fast_reg_cqe,
1220                         .mr = req->mr,
1221                         .key = req->mr->rkey,
1222                         .access = (IB_ACCESS_LOCAL_WRITE |
1223                                    IB_ACCESS_REMOTE_WRITE),
1224                 };
1225                 wr = &rwr.wr;
1226
1227                 msg->sg_cnt = cpu_to_le16(1);
1228                 msg->flags = cpu_to_le16(RTRS_MSG_NEED_INVAL_F);
1229
1230                 msg->desc[0].addr = cpu_to_le64(req->mr->iova);
1231                 msg->desc[0].key = cpu_to_le32(req->mr->rkey);
1232                 msg->desc[0].len = cpu_to_le32(req->mr->length);
1233
1234                 /* Further invalidation is required */
1235                 req->need_inv = !!RTRS_MSG_NEED_INVAL_F;
1236
1237         } else {
1238                 msg->sg_cnt = 0;
1239                 msg->flags = 0;
1240         }
1241         /*
1242          * rtrs message will be after the space reserved for disk data and
1243          * user message
1244          */
1245         imm = req->permit->mem_off + req->data_len + req->usr_len;
1246         imm = rtrs_to_io_req_imm(imm);
1247         buf_id = req->permit->mem_id;
1248
1249         req->sg_size  = sizeof(*msg);
1250         req->sg_size += le16_to_cpu(msg->sg_cnt) * sizeof(struct rtrs_sg_desc);
1251         req->sg_size += req->usr_len;
1252
1253         /*
1254          * Update stats now, after request is successfully sent it is not
1255          * safe anymore to touch it.
1256          */
1257         rtrs_clt_update_all_stats(req, READ);
1258
1259         ret = rtrs_post_send_rdma(req->con, req, &clt_path->rbufs[buf_id],
1260                                    req->data_len, imm, wr);
1261         if (ret) {
1262                 rtrs_err_rl(s,
1263                             "Read request failed: error=%d path=%s [%s:%u]\n",
1264                             ret, kobject_name(&clt_path->kobj), clt_path->hca_name,
1265                             clt_path->hca_port);
1266                 if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
1267                         atomic_dec(&clt_path->stats->inflight);
1268                 req->need_inv = false;
1269                 if (req->sg_cnt)
1270                         ib_dma_unmap_sg(dev->ib_dev, req->sglist,
1271                                         req->sg_cnt, req->dir);
1272         }
1273
1274         return ret;
1275 }
1276
1277 /**
1278  * rtrs_clt_failover_req() - Try to find an active path for a failed request
1279  * @clt: clt context
1280  * @fail_req: a failed io request.
1281  */
1282 static int rtrs_clt_failover_req(struct rtrs_clt_sess *clt,
1283                                  struct rtrs_clt_io_req *fail_req)
1284 {
1285         struct rtrs_clt_path *alive_path;
1286         struct rtrs_clt_io_req *req;
1287         int err = -ECONNABORTED;
1288         struct path_it it;
1289
1290         rcu_read_lock();
1291         for (path_it_init(&it, clt);
1292              (alive_path = it.next_path(&it)) && it.i < it.clt->paths_num;
1293              it.i++) {
1294                 if (READ_ONCE(alive_path->state) != RTRS_CLT_CONNECTED)
1295                         continue;
1296                 req = rtrs_clt_get_copy_req(alive_path, fail_req);
1297                 if (req->dir == DMA_TO_DEVICE)
1298                         err = rtrs_clt_write_req(req);
1299                 else
1300                         err = rtrs_clt_read_req(req);
1301                 if (err) {
1302                         req->in_use = false;
1303                         continue;
1304                 }
1305                 /* Success path */
1306                 rtrs_clt_inc_failover_cnt(alive_path->stats);
1307                 break;
1308         }
1309         path_it_deinit(&it);
1310         rcu_read_unlock();
1311
1312         return err;
1313 }
1314
1315 static void fail_all_outstanding_reqs(struct rtrs_clt_path *clt_path)
1316 {
1317         struct rtrs_clt_sess *clt = clt_path->clt;
1318         struct rtrs_clt_io_req *req;
1319         int i, err;
1320
1321         if (!clt_path->reqs)
1322                 return;
1323         for (i = 0; i < clt_path->queue_depth; ++i) {
1324                 req = &clt_path->reqs[i];
1325                 if (!req->in_use)
1326                         continue;
1327
1328                 /*
1329                  * Safely (without notification) complete failed request.
1330                  * After completion this request is still useble and can
1331                  * be failovered to another path.
1332                  */
1333                 complete_rdma_req(req, -ECONNABORTED, false, true);
1334
1335                 err = rtrs_clt_failover_req(clt, req);
1336                 if (err)
1337                         /* Failover failed, notify anyway */
1338                         req->conf(req->priv, err);
1339         }
1340 }
1341
1342 static void free_path_reqs(struct rtrs_clt_path *clt_path)
1343 {
1344         struct rtrs_clt_io_req *req;
1345         int i;
1346
1347         if (!clt_path->reqs)
1348                 return;
1349         for (i = 0; i < clt_path->queue_depth; ++i) {
1350                 req = &clt_path->reqs[i];
1351                 if (req->mr)
1352                         ib_dereg_mr(req->mr);
1353                 kfree(req->sge);
1354                 rtrs_iu_free(req->iu, clt_path->s.dev->ib_dev, 1);
1355         }
1356         kfree(clt_path->reqs);
1357         clt_path->reqs = NULL;
1358 }
1359
1360 static int alloc_path_reqs(struct rtrs_clt_path *clt_path)
1361 {
1362         struct rtrs_clt_io_req *req;
1363         int i, err = -ENOMEM;
1364
1365         clt_path->reqs = kcalloc(clt_path->queue_depth,
1366                                  sizeof(*clt_path->reqs),
1367                                  GFP_KERNEL);
1368         if (!clt_path->reqs)
1369                 return -ENOMEM;
1370
1371         for (i = 0; i < clt_path->queue_depth; ++i) {
1372                 req = &clt_path->reqs[i];
1373                 req->iu = rtrs_iu_alloc(1, clt_path->max_hdr_size, GFP_KERNEL,
1374                                          clt_path->s.dev->ib_dev,
1375                                          DMA_TO_DEVICE,
1376                                          rtrs_clt_rdma_done);
1377                 if (!req->iu)
1378                         goto out;
1379
1380                 req->sge = kcalloc(2, sizeof(*req->sge), GFP_KERNEL);
1381                 if (!req->sge)
1382                         goto out;
1383
1384                 req->mr = ib_alloc_mr(clt_path->s.dev->ib_pd,
1385                                       IB_MR_TYPE_MEM_REG,
1386                                       clt_path->max_pages_per_mr);
1387                 if (IS_ERR(req->mr)) {
1388                         err = PTR_ERR(req->mr);
1389                         req->mr = NULL;
1390                         pr_err("Failed to alloc clt_path->max_pages_per_mr %d\n",
1391                                clt_path->max_pages_per_mr);
1392                         goto out;
1393                 }
1394
1395                 init_completion(&req->inv_comp);
1396         }
1397
1398         return 0;
1399
1400 out:
1401         free_path_reqs(clt_path);
1402
1403         return err;
1404 }
1405
1406 static int alloc_permits(struct rtrs_clt_sess *clt)
1407 {
1408         unsigned int chunk_bits;
1409         int err, i;
1410
1411         clt->permits_map = bitmap_zalloc(clt->queue_depth, GFP_KERNEL);
1412         if (!clt->permits_map) {
1413                 err = -ENOMEM;
1414                 goto out_err;
1415         }
1416         clt->permits = kcalloc(clt->queue_depth, permit_size(clt), GFP_KERNEL);
1417         if (!clt->permits) {
1418                 err = -ENOMEM;
1419                 goto err_map;
1420         }
1421         chunk_bits = ilog2(clt->queue_depth - 1) + 1;
1422         for (i = 0; i < clt->queue_depth; i++) {
1423                 struct rtrs_permit *permit;
1424
1425                 permit = get_permit(clt, i);
1426                 permit->mem_id = i;
1427                 permit->mem_off = i << (MAX_IMM_PAYL_BITS - chunk_bits);
1428         }
1429
1430         return 0;
1431
1432 err_map:
1433         bitmap_free(clt->permits_map);
1434         clt->permits_map = NULL;
1435 out_err:
1436         return err;
1437 }
1438
1439 static void free_permits(struct rtrs_clt_sess *clt)
1440 {
1441         if (clt->permits_map)
1442                 wait_event(clt->permits_wait,
1443                            bitmap_empty(clt->permits_map, clt->queue_depth));
1444
1445         bitmap_free(clt->permits_map);
1446         clt->permits_map = NULL;
1447         kfree(clt->permits);
1448         clt->permits = NULL;
1449 }
1450
1451 static void query_fast_reg_mode(struct rtrs_clt_path *clt_path)
1452 {
1453         struct ib_device *ib_dev;
1454         u64 max_pages_per_mr;
1455         int mr_page_shift;
1456
1457         ib_dev = clt_path->s.dev->ib_dev;
1458
1459         /*
1460          * Use the smallest page size supported by the HCA, down to a
1461          * minimum of 4096 bytes. We're unlikely to build large sglists
1462          * out of smaller entries.
1463          */
1464         mr_page_shift      = max(12, ffs(ib_dev->attrs.page_size_cap) - 1);
1465         max_pages_per_mr   = ib_dev->attrs.max_mr_size;
1466         do_div(max_pages_per_mr, (1ull << mr_page_shift));
1467         clt_path->max_pages_per_mr =
1468                 min3(clt_path->max_pages_per_mr, (u32)max_pages_per_mr,
1469                      ib_dev->attrs.max_fast_reg_page_list_len);
1470         clt_path->clt->max_segments =
1471                 min(clt_path->max_pages_per_mr, clt_path->clt->max_segments);
1472 }
1473
1474 static bool rtrs_clt_change_state_get_old(struct rtrs_clt_path *clt_path,
1475                                            enum rtrs_clt_state new_state,
1476                                            enum rtrs_clt_state *old_state)
1477 {
1478         bool changed;
1479
1480         spin_lock_irq(&clt_path->state_wq.lock);
1481         if (old_state)
1482                 *old_state = clt_path->state;
1483         changed = rtrs_clt_change_state(clt_path, new_state);
1484         spin_unlock_irq(&clt_path->state_wq.lock);
1485
1486         return changed;
1487 }
1488
1489 static void rtrs_clt_hb_err_handler(struct rtrs_con *c)
1490 {
1491         struct rtrs_clt_con *con = container_of(c, typeof(*con), c);
1492
1493         rtrs_rdma_error_recovery(con);
1494 }
1495
1496 static void rtrs_clt_init_hb(struct rtrs_clt_path *clt_path)
1497 {
1498         rtrs_init_hb(&clt_path->s, &io_comp_cqe,
1499                       RTRS_HB_INTERVAL_MS,
1500                       RTRS_HB_MISSED_MAX,
1501                       rtrs_clt_hb_err_handler,
1502                       rtrs_wq);
1503 }
1504
1505 static void rtrs_clt_reconnect_work(struct work_struct *work);
1506 static void rtrs_clt_close_work(struct work_struct *work);
1507
1508 static void rtrs_clt_err_recovery_work(struct work_struct *work)
1509 {
1510         struct rtrs_clt_path *clt_path;
1511         struct rtrs_clt_sess *clt;
1512         int delay_ms;
1513
1514         clt_path = container_of(work, struct rtrs_clt_path, err_recovery_work);
1515         clt = clt_path->clt;
1516         delay_ms = clt->reconnect_delay_sec * 1000;
1517         rtrs_clt_stop_and_destroy_conns(clt_path);
1518         queue_delayed_work(rtrs_wq, &clt_path->reconnect_dwork,
1519                            msecs_to_jiffies(delay_ms +
1520                                             get_random_u32_below(RTRS_RECONNECT_SEED)));
1521 }
1522
1523 static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt,
1524                                         const struct rtrs_addr *path,
1525                                         size_t con_num, u32 nr_poll_queues)
1526 {
1527         struct rtrs_clt_path *clt_path;
1528         int err = -ENOMEM;
1529         int cpu;
1530         size_t total_con;
1531
1532         clt_path = kzalloc(sizeof(*clt_path), GFP_KERNEL);
1533         if (!clt_path)
1534                 goto err;
1535
1536         /*
1537          * irqmode and poll
1538          * +1: Extra connection for user messages
1539          */
1540         total_con = con_num + nr_poll_queues + 1;
1541         clt_path->s.con = kcalloc(total_con, sizeof(*clt_path->s.con),
1542                                   GFP_KERNEL);
1543         if (!clt_path->s.con)
1544                 goto err_free_path;
1545
1546         clt_path->s.con_num = total_con;
1547         clt_path->s.irq_con_num = con_num + 1;
1548
1549         clt_path->stats = kzalloc(sizeof(*clt_path->stats), GFP_KERNEL);
1550         if (!clt_path->stats)
1551                 goto err_free_con;
1552
1553         mutex_init(&clt_path->init_mutex);
1554         uuid_gen(&clt_path->s.uuid);
1555         memcpy(&clt_path->s.dst_addr, path->dst,
1556                rdma_addr_size((struct sockaddr *)path->dst));
1557
1558         /*
1559          * rdma_resolve_addr() passes src_addr to cma_bind_addr, which
1560          * checks the sa_family to be non-zero. If user passed src_addr=NULL
1561          * the sess->src_addr will contain only zeros, which is then fine.
1562          */
1563         if (path->src)
1564                 memcpy(&clt_path->s.src_addr, path->src,
1565                        rdma_addr_size((struct sockaddr *)path->src));
1566         strscpy(clt_path->s.sessname, clt->sessname,
1567                 sizeof(clt_path->s.sessname));
1568         clt_path->clt = clt;
1569         clt_path->max_pages_per_mr = RTRS_MAX_SEGMENTS;
1570         init_waitqueue_head(&clt_path->state_wq);
1571         clt_path->state = RTRS_CLT_CONNECTING;
1572         atomic_set(&clt_path->connected_cnt, 0);
1573         INIT_WORK(&clt_path->close_work, rtrs_clt_close_work);
1574         INIT_WORK(&clt_path->err_recovery_work, rtrs_clt_err_recovery_work);
1575         INIT_DELAYED_WORK(&clt_path->reconnect_dwork, rtrs_clt_reconnect_work);
1576         rtrs_clt_init_hb(clt_path);
1577
1578         clt_path->mp_skip_entry = alloc_percpu(typeof(*clt_path->mp_skip_entry));
1579         if (!clt_path->mp_skip_entry)
1580                 goto err_free_stats;
1581
1582         for_each_possible_cpu(cpu)
1583                 INIT_LIST_HEAD(per_cpu_ptr(clt_path->mp_skip_entry, cpu));
1584
1585         err = rtrs_clt_init_stats(clt_path->stats);
1586         if (err)
1587                 goto err_free_percpu;
1588
1589         return clt_path;
1590
1591 err_free_percpu:
1592         free_percpu(clt_path->mp_skip_entry);
1593 err_free_stats:
1594         kfree(clt_path->stats);
1595 err_free_con:
1596         kfree(clt_path->s.con);
1597 err_free_path:
1598         kfree(clt_path);
1599 err:
1600         return ERR_PTR(err);
1601 }
1602
1603 void free_path(struct rtrs_clt_path *clt_path)
1604 {
1605         free_percpu(clt_path->mp_skip_entry);
1606         mutex_destroy(&clt_path->init_mutex);
1607         kfree(clt_path->s.con);
1608         kfree(clt_path->rbufs);
1609         kfree(clt_path);
1610 }
1611
1612 static int create_con(struct rtrs_clt_path *clt_path, unsigned int cid)
1613 {
1614         struct rtrs_clt_con *con;
1615
1616         con = kzalloc(sizeof(*con), GFP_KERNEL);
1617         if (!con)
1618                 return -ENOMEM;
1619
1620         /* Map first two connections to the first CPU */
1621         con->cpu  = (cid ? cid - 1 : 0) % nr_cpu_ids;
1622         con->c.cid = cid;
1623         con->c.path = &clt_path->s;
1624         /* Align with srv, init as 1 */
1625         atomic_set(&con->c.wr_cnt, 1);
1626         mutex_init(&con->con_mutex);
1627
1628         clt_path->s.con[cid] = &con->c;
1629
1630         return 0;
1631 }
1632
1633 static void destroy_con(struct rtrs_clt_con *con)
1634 {
1635         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1636
1637         clt_path->s.con[con->c.cid] = NULL;
1638         mutex_destroy(&con->con_mutex);
1639         kfree(con);
1640 }
1641
1642 static int create_con_cq_qp(struct rtrs_clt_con *con)
1643 {
1644         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1645         u32 max_send_wr, max_recv_wr, cq_num, max_send_sge, wr_limit;
1646         int err, cq_vector;
1647         struct rtrs_msg_rkey_rsp *rsp;
1648
1649         lockdep_assert_held(&con->con_mutex);
1650         if (con->c.cid == 0) {
1651                 max_send_sge = 1;
1652                 /* We must be the first here */
1653                 if (WARN_ON(clt_path->s.dev))
1654                         return -EINVAL;
1655
1656                 /*
1657                  * The whole session uses device from user connection.
1658                  * Be careful not to close user connection before ib dev
1659                  * is gracefully put.
1660                  */
1661                 clt_path->s.dev = rtrs_ib_dev_find_or_add(con->c.cm_id->device,
1662                                                        &dev_pd);
1663                 if (!clt_path->s.dev) {
1664                         rtrs_wrn(clt_path->clt,
1665                                   "rtrs_ib_dev_find_get_or_add(): no memory\n");
1666                         return -ENOMEM;
1667                 }
1668                 clt_path->s.dev_ref = 1;
1669                 query_fast_reg_mode(clt_path);
1670                 wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr;
1671                 /*
1672                  * Two (request + registration) completion for send
1673                  * Two for recv if always_invalidate is set on server
1674                  * or one for recv.
1675                  * + 2 for drain and heartbeat
1676                  * in case qp gets into error state.
1677                  */
1678                 max_send_wr =
1679                         min_t(int, wr_limit, SERVICE_CON_QUEUE_DEPTH * 2 + 2);
1680                 max_recv_wr = max_send_wr;
1681         } else {
1682                 /*
1683                  * Here we assume that session members are correctly set.
1684                  * This is always true if user connection (cid == 0) is
1685                  * established first.
1686                  */
1687                 if (WARN_ON(!clt_path->s.dev))
1688                         return -EINVAL;
1689                 if (WARN_ON(!clt_path->queue_depth))
1690                         return -EINVAL;
1691
1692                 wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr;
1693                 /* Shared between connections */
1694                 clt_path->s.dev_ref++;
1695                 max_send_wr = min_t(int, wr_limit,
1696                               /* QD * (REQ + RSP + FR REGS or INVS) + drain */
1697                               clt_path->queue_depth * 3 + 1);
1698                 max_recv_wr = min_t(int, wr_limit,
1699                               clt_path->queue_depth * 3 + 1);
1700                 max_send_sge = 2;
1701         }
1702         atomic_set(&con->c.sq_wr_avail, max_send_wr);
1703         cq_num = max_send_wr + max_recv_wr;
1704         /* alloc iu to recv new rkey reply when server reports flags set */
1705         if (clt_path->flags & RTRS_MSG_NEW_RKEY_F || con->c.cid == 0) {
1706                 con->rsp_ius = rtrs_iu_alloc(cq_num, sizeof(*rsp),
1707                                               GFP_KERNEL,
1708                                               clt_path->s.dev->ib_dev,
1709                                               DMA_FROM_DEVICE,
1710                                               rtrs_clt_rdma_done);
1711                 if (!con->rsp_ius)
1712                         return -ENOMEM;
1713                 con->queue_num = cq_num;
1714         }
1715         cq_vector = con->cpu % clt_path->s.dev->ib_dev->num_comp_vectors;
1716         if (con->c.cid >= clt_path->s.irq_con_num)
1717                 err = rtrs_cq_qp_create(&clt_path->s, &con->c, max_send_sge,
1718                                         cq_vector, cq_num, max_send_wr,
1719                                         max_recv_wr, IB_POLL_DIRECT);
1720         else
1721                 err = rtrs_cq_qp_create(&clt_path->s, &con->c, max_send_sge,
1722                                         cq_vector, cq_num, max_send_wr,
1723                                         max_recv_wr, IB_POLL_SOFTIRQ);
1724         /*
1725          * In case of error we do not bother to clean previous allocations,
1726          * since destroy_con_cq_qp() must be called.
1727          */
1728         return err;
1729 }
1730
1731 static void destroy_con_cq_qp(struct rtrs_clt_con *con)
1732 {
1733         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1734
1735         /*
1736          * Be careful here: destroy_con_cq_qp() can be called even
1737          * create_con_cq_qp() failed, see comments there.
1738          */
1739         lockdep_assert_held(&con->con_mutex);
1740         rtrs_cq_qp_destroy(&con->c);
1741         if (con->rsp_ius) {
1742                 rtrs_iu_free(con->rsp_ius, clt_path->s.dev->ib_dev,
1743                              con->queue_num);
1744                 con->rsp_ius = NULL;
1745                 con->queue_num = 0;
1746         }
1747         if (clt_path->s.dev_ref && !--clt_path->s.dev_ref) {
1748                 rtrs_ib_dev_put(clt_path->s.dev);
1749                 clt_path->s.dev = NULL;
1750         }
1751 }
1752
1753 static void stop_cm(struct rtrs_clt_con *con)
1754 {
1755         rdma_disconnect(con->c.cm_id);
1756         if (con->c.qp)
1757                 ib_drain_qp(con->c.qp);
1758 }
1759
1760 static void destroy_cm(struct rtrs_clt_con *con)
1761 {
1762         rdma_destroy_id(con->c.cm_id);
1763         con->c.cm_id = NULL;
1764 }
1765
1766 static int rtrs_rdma_addr_resolved(struct rtrs_clt_con *con)
1767 {
1768         struct rtrs_path *s = con->c.path;
1769         int err;
1770
1771         mutex_lock(&con->con_mutex);
1772         err = create_con_cq_qp(con);
1773         mutex_unlock(&con->con_mutex);
1774         if (err) {
1775                 rtrs_err(s, "create_con_cq_qp(), err: %d\n", err);
1776                 return err;
1777         }
1778         err = rdma_resolve_route(con->c.cm_id, RTRS_CONNECT_TIMEOUT_MS);
1779         if (err)
1780                 rtrs_err(s, "Resolving route failed, err: %d\n", err);
1781
1782         return err;
1783 }
1784
1785 static int rtrs_rdma_route_resolved(struct rtrs_clt_con *con)
1786 {
1787         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1788         struct rtrs_clt_sess *clt = clt_path->clt;
1789         struct rtrs_msg_conn_req msg;
1790         struct rdma_conn_param param;
1791
1792         int err;
1793
1794         param = (struct rdma_conn_param) {
1795                 .retry_count = 7,
1796                 .rnr_retry_count = 7,
1797                 .private_data = &msg,
1798                 .private_data_len = sizeof(msg),
1799         };
1800
1801         msg = (struct rtrs_msg_conn_req) {
1802                 .magic = cpu_to_le16(RTRS_MAGIC),
1803                 .version = cpu_to_le16(RTRS_PROTO_VER),
1804                 .cid = cpu_to_le16(con->c.cid),
1805                 .cid_num = cpu_to_le16(clt_path->s.con_num),
1806                 .recon_cnt = cpu_to_le16(clt_path->s.recon_cnt),
1807         };
1808         msg.first_conn = clt_path->for_new_clt ? FIRST_CONN : 0;
1809         uuid_copy(&msg.sess_uuid, &clt_path->s.uuid);
1810         uuid_copy(&msg.paths_uuid, &clt->paths_uuid);
1811
1812         err = rdma_connect_locked(con->c.cm_id, &param);
1813         if (err)
1814                 rtrs_err(clt, "rdma_connect_locked(): %d\n", err);
1815
1816         return err;
1817 }
1818
1819 static int rtrs_rdma_conn_established(struct rtrs_clt_con *con,
1820                                        struct rdma_cm_event *ev)
1821 {
1822         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1823         struct rtrs_clt_sess *clt = clt_path->clt;
1824         const struct rtrs_msg_conn_rsp *msg;
1825         u16 version, queue_depth;
1826         int errno;
1827         u8 len;
1828
1829         msg = ev->param.conn.private_data;
1830         len = ev->param.conn.private_data_len;
1831         if (len < sizeof(*msg)) {
1832                 rtrs_err(clt, "Invalid RTRS connection response\n");
1833                 return -ECONNRESET;
1834         }
1835         if (le16_to_cpu(msg->magic) != RTRS_MAGIC) {
1836                 rtrs_err(clt, "Invalid RTRS magic\n");
1837                 return -ECONNRESET;
1838         }
1839         version = le16_to_cpu(msg->version);
1840         if (version >> 8 != RTRS_PROTO_VER_MAJOR) {
1841                 rtrs_err(clt, "Unsupported major RTRS version: %d, expected %d\n",
1842                           version >> 8, RTRS_PROTO_VER_MAJOR);
1843                 return -ECONNRESET;
1844         }
1845         errno = le16_to_cpu(msg->errno);
1846         if (errno) {
1847                 rtrs_err(clt, "Invalid RTRS message: errno %d\n",
1848                           errno);
1849                 return -ECONNRESET;
1850         }
1851         if (con->c.cid == 0) {
1852                 queue_depth = le16_to_cpu(msg->queue_depth);
1853
1854                 if (clt_path->queue_depth > 0 && queue_depth != clt_path->queue_depth) {
1855                         rtrs_err(clt, "Error: queue depth changed\n");
1856
1857                         /*
1858                          * Stop any more reconnection attempts
1859                          */
1860                         clt_path->reconnect_attempts = -1;
1861                         rtrs_err(clt,
1862                                 "Disabling auto-reconnect. Trigger a manual reconnect after issue is resolved\n");
1863                         return -ECONNRESET;
1864                 }
1865
1866                 if (!clt_path->rbufs) {
1867                         clt_path->rbufs = kcalloc(queue_depth,
1868                                                   sizeof(*clt_path->rbufs),
1869                                                   GFP_KERNEL);
1870                         if (!clt_path->rbufs)
1871                                 return -ENOMEM;
1872                 }
1873                 clt_path->queue_depth = queue_depth;
1874                 clt_path->s.signal_interval = min_not_zero(queue_depth,
1875                                                 (unsigned short) SERVICE_CON_QUEUE_DEPTH);
1876                 clt_path->max_hdr_size = le32_to_cpu(msg->max_hdr_size);
1877                 clt_path->max_io_size = le32_to_cpu(msg->max_io_size);
1878                 clt_path->flags = le32_to_cpu(msg->flags);
1879                 clt_path->chunk_size = clt_path->max_io_size + clt_path->max_hdr_size;
1880
1881                 /*
1882                  * Global IO size is always a minimum.
1883                  * If while a reconnection server sends us a value a bit
1884                  * higher - client does not care and uses cached minimum.
1885                  *
1886                  * Since we can have several sessions (paths) restablishing
1887                  * connections in parallel, use lock.
1888                  */
1889                 mutex_lock(&clt->paths_mutex);
1890                 clt->queue_depth = clt_path->queue_depth;
1891                 clt->max_io_size = min_not_zero(clt_path->max_io_size,
1892                                                 clt->max_io_size);
1893                 mutex_unlock(&clt->paths_mutex);
1894
1895                 /*
1896                  * Cache the hca_port and hca_name for sysfs
1897                  */
1898                 clt_path->hca_port = con->c.cm_id->port_num;
1899                 scnprintf(clt_path->hca_name, sizeof(clt_path->hca_name),
1900                           clt_path->s.dev->ib_dev->name);
1901                 clt_path->s.src_addr = con->c.cm_id->route.addr.src_addr;
1902                 /* set for_new_clt, to allow future reconnect on any path */
1903                 clt_path->for_new_clt = 1;
1904         }
1905
1906         return 0;
1907 }
1908
1909 static inline void flag_success_on_conn(struct rtrs_clt_con *con)
1910 {
1911         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1912
1913         atomic_inc(&clt_path->connected_cnt);
1914         con->cm_err = 1;
1915 }
1916
1917 static int rtrs_rdma_conn_rejected(struct rtrs_clt_con *con,
1918                                     struct rdma_cm_event *ev)
1919 {
1920         struct rtrs_path *s = con->c.path;
1921         const struct rtrs_msg_conn_rsp *msg;
1922         const char *rej_msg;
1923         int status, errno;
1924         u8 data_len;
1925
1926         status = ev->status;
1927         rej_msg = rdma_reject_msg(con->c.cm_id, status);
1928         msg = rdma_consumer_reject_data(con->c.cm_id, ev, &data_len);
1929
1930         if (msg && data_len >= sizeof(*msg)) {
1931                 errno = (int16_t)le16_to_cpu(msg->errno);
1932                 if (errno == -EBUSY)
1933                         rtrs_err(s,
1934                                   "Previous session is still exists on the server, please reconnect later\n");
1935                 else
1936                         rtrs_err(s,
1937                                   "Connect rejected: status %d (%s), rtrs errno %d\n",
1938                                   status, rej_msg, errno);
1939         } else {
1940                 rtrs_err(s,
1941                           "Connect rejected but with malformed message: status %d (%s)\n",
1942                           status, rej_msg);
1943         }
1944
1945         return -ECONNRESET;
1946 }
1947
1948 void rtrs_clt_close_conns(struct rtrs_clt_path *clt_path, bool wait)
1949 {
1950         trace_rtrs_clt_close_conns(clt_path);
1951
1952         if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CLOSING, NULL))
1953                 queue_work(rtrs_wq, &clt_path->close_work);
1954         if (wait)
1955                 flush_work(&clt_path->close_work);
1956 }
1957
1958 static inline void flag_error_on_conn(struct rtrs_clt_con *con, int cm_err)
1959 {
1960         if (con->cm_err == 1) {
1961                 struct rtrs_clt_path *clt_path;
1962
1963                 clt_path = to_clt_path(con->c.path);
1964                 if (atomic_dec_and_test(&clt_path->connected_cnt))
1965
1966                         wake_up(&clt_path->state_wq);
1967         }
1968         con->cm_err = cm_err;
1969 }
1970
1971 static int rtrs_clt_rdma_cm_handler(struct rdma_cm_id *cm_id,
1972                                      struct rdma_cm_event *ev)
1973 {
1974         struct rtrs_clt_con *con = cm_id->context;
1975         struct rtrs_path *s = con->c.path;
1976         struct rtrs_clt_path *clt_path = to_clt_path(s);
1977         int cm_err = 0;
1978
1979         switch (ev->event) {
1980         case RDMA_CM_EVENT_ADDR_RESOLVED:
1981                 cm_err = rtrs_rdma_addr_resolved(con);
1982                 break;
1983         case RDMA_CM_EVENT_ROUTE_RESOLVED:
1984                 cm_err = rtrs_rdma_route_resolved(con);
1985                 break;
1986         case RDMA_CM_EVENT_ESTABLISHED:
1987                 cm_err = rtrs_rdma_conn_established(con, ev);
1988                 if (!cm_err) {
1989                         /*
1990                          * Report success and wake up. Here we abuse state_wq,
1991                          * i.e. wake up without state change, but we set cm_err.
1992                          */
1993                         flag_success_on_conn(con);
1994                         wake_up(&clt_path->state_wq);
1995                         return 0;
1996                 }
1997                 break;
1998         case RDMA_CM_EVENT_REJECTED:
1999                 cm_err = rtrs_rdma_conn_rejected(con, ev);
2000                 break;
2001         case RDMA_CM_EVENT_DISCONNECTED:
2002                 /* No message for disconnecting */
2003                 cm_err = -ECONNRESET;
2004                 break;
2005         case RDMA_CM_EVENT_CONNECT_ERROR:
2006         case RDMA_CM_EVENT_UNREACHABLE:
2007         case RDMA_CM_EVENT_ADDR_CHANGE:
2008         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
2009                 rtrs_wrn(s, "CM error (CM event: %s, err: %d)\n",
2010                          rdma_event_msg(ev->event), ev->status);
2011                 cm_err = -ECONNRESET;
2012                 break;
2013         case RDMA_CM_EVENT_ADDR_ERROR:
2014         case RDMA_CM_EVENT_ROUTE_ERROR:
2015                 rtrs_wrn(s, "CM error (CM event: %s, err: %d)\n",
2016                          rdma_event_msg(ev->event), ev->status);
2017                 cm_err = -EHOSTUNREACH;
2018                 break;
2019         case RDMA_CM_EVENT_DEVICE_REMOVAL:
2020                 /*
2021                  * Device removal is a special case.  Queue close and return 0.
2022                  */
2023                 rtrs_clt_close_conns(clt_path, false);
2024                 return 0;
2025         default:
2026                 rtrs_err(s, "Unexpected RDMA CM error (CM event: %s, err: %d)\n",
2027                          rdma_event_msg(ev->event), ev->status);
2028                 cm_err = -ECONNRESET;
2029                 break;
2030         }
2031
2032         if (cm_err) {
2033                 /*
2034                  * cm error makes sense only on connection establishing,
2035                  * in other cases we rely on normal procedure of reconnecting.
2036                  */
2037                 flag_error_on_conn(con, cm_err);
2038                 rtrs_rdma_error_recovery(con);
2039         }
2040
2041         return 0;
2042 }
2043
2044 /* The caller should do the cleanup in case of error */
2045 static int create_cm(struct rtrs_clt_con *con)
2046 {
2047         struct rtrs_path *s = con->c.path;
2048         struct rtrs_clt_path *clt_path = to_clt_path(s);
2049         struct rdma_cm_id *cm_id;
2050         int err;
2051
2052         cm_id = rdma_create_id(&init_net, rtrs_clt_rdma_cm_handler, con,
2053                                clt_path->s.dst_addr.ss_family == AF_IB ?
2054                                RDMA_PS_IB : RDMA_PS_TCP, IB_QPT_RC);
2055         if (IS_ERR(cm_id)) {
2056                 err = PTR_ERR(cm_id);
2057                 rtrs_err(s, "Failed to create CM ID, err: %d\n", err);
2058
2059                 return err;
2060         }
2061         con->c.cm_id = cm_id;
2062         con->cm_err = 0;
2063         /* allow the port to be reused */
2064         err = rdma_set_reuseaddr(cm_id, 1);
2065         if (err != 0) {
2066                 rtrs_err(s, "Set address reuse failed, err: %d\n", err);
2067                 return err;
2068         }
2069         err = rdma_resolve_addr(cm_id, (struct sockaddr *)&clt_path->s.src_addr,
2070                                 (struct sockaddr *)&clt_path->s.dst_addr,
2071                                 RTRS_CONNECT_TIMEOUT_MS);
2072         if (err) {
2073                 rtrs_err(s, "Failed to resolve address, err: %d\n", err);
2074                 return err;
2075         }
2076         /*
2077          * Combine connection status and session events. This is needed
2078          * for waiting two possible cases: cm_err has something meaningful
2079          * or session state was really changed to error by device removal.
2080          */
2081         err = wait_event_interruptible_timeout(
2082                         clt_path->state_wq,
2083                         con->cm_err || clt_path->state != RTRS_CLT_CONNECTING,
2084                         msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS));
2085         if (err == 0 || err == -ERESTARTSYS) {
2086                 if (err == 0)
2087                         err = -ETIMEDOUT;
2088                 /* Timedout or interrupted */
2089                 return err;
2090         }
2091         if (con->cm_err < 0)
2092                 return con->cm_err;
2093         if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTING)
2094                 /* Device removal */
2095                 return -ECONNABORTED;
2096
2097         return 0;
2098 }
2099
2100 static void rtrs_clt_path_up(struct rtrs_clt_path *clt_path)
2101 {
2102         struct rtrs_clt_sess *clt = clt_path->clt;
2103         int up;
2104
2105         /*
2106          * We can fire RECONNECTED event only when all paths were
2107          * connected on rtrs_clt_open(), then each was disconnected
2108          * and the first one connected again.  That's why this nasty
2109          * game with counter value.
2110          */
2111
2112         mutex_lock(&clt->paths_ev_mutex);
2113         up = ++clt->paths_up;
2114         /*
2115          * Here it is safe to access paths num directly since up counter
2116          * is greater than MAX_PATHS_NUM only while rtrs_clt_open() is
2117          * in progress, thus paths removals are impossible.
2118          */
2119         if (up > MAX_PATHS_NUM && up == MAX_PATHS_NUM + clt->paths_num)
2120                 clt->paths_up = clt->paths_num;
2121         else if (up == 1)
2122                 clt->link_ev(clt->priv, RTRS_CLT_LINK_EV_RECONNECTED);
2123         mutex_unlock(&clt->paths_ev_mutex);
2124
2125         /* Mark session as established */
2126         clt_path->established = true;
2127         clt_path->reconnect_attempts = 0;
2128         clt_path->stats->reconnects.successful_cnt++;
2129 }
2130
2131 static void rtrs_clt_path_down(struct rtrs_clt_path *clt_path)
2132 {
2133         struct rtrs_clt_sess *clt = clt_path->clt;
2134
2135         if (!clt_path->established)
2136                 return;
2137
2138         clt_path->established = false;
2139         mutex_lock(&clt->paths_ev_mutex);
2140         WARN_ON(!clt->paths_up);
2141         if (--clt->paths_up == 0)
2142                 clt->link_ev(clt->priv, RTRS_CLT_LINK_EV_DISCONNECTED);
2143         mutex_unlock(&clt->paths_ev_mutex);
2144 }
2145
2146 static void rtrs_clt_stop_and_destroy_conns(struct rtrs_clt_path *clt_path)
2147 {
2148         struct rtrs_clt_con *con;
2149         unsigned int cid;
2150
2151         WARN_ON(READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTED);
2152
2153         /*
2154          * Possible race with rtrs_clt_open(), when DEVICE_REMOVAL comes
2155          * exactly in between.  Start destroying after it finishes.
2156          */
2157         mutex_lock(&clt_path->init_mutex);
2158         mutex_unlock(&clt_path->init_mutex);
2159
2160         /*
2161          * All IO paths must observe !CONNECTED state before we
2162          * free everything.
2163          */
2164         synchronize_rcu();
2165
2166         rtrs_stop_hb(&clt_path->s);
2167
2168         /*
2169          * The order it utterly crucial: firstly disconnect and complete all
2170          * rdma requests with error (thus set in_use=false for requests),
2171          * then fail outstanding requests checking in_use for each, and
2172          * eventually notify upper layer about session disconnection.
2173          */
2174
2175         for (cid = 0; cid < clt_path->s.con_num; cid++) {
2176                 if (!clt_path->s.con[cid])
2177                         break;
2178                 con = to_clt_con(clt_path->s.con[cid]);
2179                 stop_cm(con);
2180         }
2181         fail_all_outstanding_reqs(clt_path);
2182         free_path_reqs(clt_path);
2183         rtrs_clt_path_down(clt_path);
2184
2185         /*
2186          * Wait for graceful shutdown, namely when peer side invokes
2187          * rdma_disconnect(). 'connected_cnt' is decremented only on
2188          * CM events, thus if other side had crashed and hb has detected
2189          * something is wrong, here we will stuck for exactly timeout ms,
2190          * since CM does not fire anything.  That is fine, we are not in
2191          * hurry.
2192          */
2193         wait_event_timeout(clt_path->state_wq,
2194                            !atomic_read(&clt_path->connected_cnt),
2195                            msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS));
2196
2197         for (cid = 0; cid < clt_path->s.con_num; cid++) {
2198                 if (!clt_path->s.con[cid])
2199                         break;
2200                 con = to_clt_con(clt_path->s.con[cid]);
2201                 mutex_lock(&con->con_mutex);
2202                 destroy_con_cq_qp(con);
2203                 mutex_unlock(&con->con_mutex);
2204                 destroy_cm(con);
2205                 destroy_con(con);
2206         }
2207 }
2208
2209 static void rtrs_clt_remove_path_from_arr(struct rtrs_clt_path *clt_path)
2210 {
2211         struct rtrs_clt_sess *clt = clt_path->clt;
2212         struct rtrs_clt_path *next;
2213         bool wait_for_grace = false;
2214         int cpu;
2215
2216         mutex_lock(&clt->paths_mutex);
2217         list_del_rcu(&clt_path->s.entry);
2218
2219         /* Make sure everybody observes path removal. */
2220         synchronize_rcu();
2221
2222         /*
2223          * At this point nobody sees @sess in the list, but still we have
2224          * dangling pointer @pcpu_path which _can_ point to @sess.  Since
2225          * nobody can observe @sess in the list, we guarantee that IO path
2226          * will not assign @sess to @pcpu_path, i.e. @pcpu_path can be equal
2227          * to @sess, but can never again become @sess.
2228          */
2229
2230         /*
2231          * Decrement paths number only after grace period, because
2232          * caller of do_each_path() must firstly observe list without
2233          * path and only then decremented paths number.
2234          *
2235          * Otherwise there can be the following situation:
2236          *    o Two paths exist and IO is coming.
2237          *    o One path is removed:
2238          *      CPU#0                          CPU#1
2239          *      do_each_path():                rtrs_clt_remove_path_from_arr():
2240          *          path = get_next_path()
2241          *          ^^^                            list_del_rcu(path)
2242          *          [!CONNECTED path]              clt->paths_num--
2243          *                                              ^^^^^^^^^
2244          *          load clt->paths_num                 from 2 to 1
2245          *                    ^^^^^^^^^
2246          *                    sees 1
2247          *
2248          *      path is observed as !CONNECTED, but do_each_path() loop
2249          *      ends, because expression i < clt->paths_num is false.
2250          */
2251         clt->paths_num--;
2252
2253         /*
2254          * Get @next connection from current @sess which is going to be
2255          * removed.  If @sess is the last element, then @next is NULL.
2256          */
2257         rcu_read_lock();
2258         next = rtrs_clt_get_next_path_or_null(&clt->paths_list, clt_path);
2259         rcu_read_unlock();
2260
2261         /*
2262          * @pcpu paths can still point to the path which is going to be
2263          * removed, so change the pointer manually.
2264          */
2265         for_each_possible_cpu(cpu) {
2266                 struct rtrs_clt_path __rcu **ppcpu_path;
2267
2268                 ppcpu_path = per_cpu_ptr(clt->pcpu_path, cpu);
2269                 if (rcu_dereference_protected(*ppcpu_path,
2270                         lockdep_is_held(&clt->paths_mutex)) != clt_path)
2271                         /*
2272                          * synchronize_rcu() was called just after deleting
2273                          * entry from the list, thus IO code path cannot
2274                          * change pointer back to the pointer which is going
2275                          * to be removed, we are safe here.
2276                          */
2277                         continue;
2278
2279                 /*
2280                  * We race with IO code path, which also changes pointer,
2281                  * thus we have to be careful not to overwrite it.
2282                  */
2283                 if (try_cmpxchg((struct rtrs_clt_path **)ppcpu_path, &clt_path,
2284                                 next))
2285                         /*
2286                          * @ppcpu_path was successfully replaced with @next,
2287                          * that means that someone could also pick up the
2288                          * @sess and dereferencing it right now, so wait for
2289                          * a grace period is required.
2290                          */
2291                         wait_for_grace = true;
2292         }
2293         if (wait_for_grace)
2294                 synchronize_rcu();
2295
2296         mutex_unlock(&clt->paths_mutex);
2297 }
2298
2299 static void rtrs_clt_add_path_to_arr(struct rtrs_clt_path *clt_path)
2300 {
2301         struct rtrs_clt_sess *clt = clt_path->clt;
2302
2303         mutex_lock(&clt->paths_mutex);
2304         clt->paths_num++;
2305
2306         list_add_tail_rcu(&clt_path->s.entry, &clt->paths_list);
2307         mutex_unlock(&clt->paths_mutex);
2308 }
2309
2310 static void rtrs_clt_close_work(struct work_struct *work)
2311 {
2312         struct rtrs_clt_path *clt_path;
2313
2314         clt_path = container_of(work, struct rtrs_clt_path, close_work);
2315
2316         cancel_work_sync(&clt_path->err_recovery_work);
2317         cancel_delayed_work_sync(&clt_path->reconnect_dwork);
2318         rtrs_clt_stop_and_destroy_conns(clt_path);
2319         rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CLOSED, NULL);
2320 }
2321
2322 static int init_conns(struct rtrs_clt_path *clt_path)
2323 {
2324         unsigned int cid;
2325         int err, i;
2326
2327         /*
2328          * On every new session connections increase reconnect counter
2329          * to avoid clashes with previous sessions not yet closed
2330          * sessions on a server side.
2331          */
2332         clt_path->s.recon_cnt++;
2333
2334         /* Establish all RDMA connections  */
2335         for (cid = 0; cid < clt_path->s.con_num; cid++) {
2336                 err = create_con(clt_path, cid);
2337                 if (err)
2338                         goto destroy;
2339
2340                 err = create_cm(to_clt_con(clt_path->s.con[cid]));
2341                 if (err)
2342                         goto destroy;
2343         }
2344         err = alloc_path_reqs(clt_path);
2345         if (err)
2346                 goto destroy;
2347
2348         return 0;
2349
2350 destroy:
2351         /* Make sure we do the cleanup in the order they are created */
2352         for (i = 0; i <= cid; i++) {
2353                 struct rtrs_clt_con *con;
2354
2355                 if (!clt_path->s.con[i])
2356                         break;
2357
2358                 con = to_clt_con(clt_path->s.con[i]);
2359                 if (con->c.cm_id) {
2360                         stop_cm(con);
2361                         mutex_lock(&con->con_mutex);
2362                         destroy_con_cq_qp(con);
2363                         mutex_unlock(&con->con_mutex);
2364                         destroy_cm(con);
2365                 }
2366                 destroy_con(con);
2367         }
2368         /*
2369          * If we've never taken async path and got an error, say,
2370          * doing rdma_resolve_addr(), switch to CONNECTION_ERR state
2371          * manually to keep reconnecting.
2372          */
2373         rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CONNECTING_ERR, NULL);
2374
2375         return err;
2376 }
2377
2378 static void rtrs_clt_info_req_done(struct ib_cq *cq, struct ib_wc *wc)
2379 {
2380         struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context);
2381         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
2382         struct rtrs_iu *iu;
2383
2384         iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
2385         rtrs_iu_free(iu, clt_path->s.dev->ib_dev, 1);
2386
2387         if (wc->status != IB_WC_SUCCESS) {
2388                 rtrs_err(clt_path->clt, "Path info request send failed: %s\n",
2389                           ib_wc_status_msg(wc->status));
2390                 rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CONNECTING_ERR, NULL);
2391                 return;
2392         }
2393
2394         rtrs_clt_update_wc_stats(con);
2395 }
2396
2397 static int process_info_rsp(struct rtrs_clt_path *clt_path,
2398                             const struct rtrs_msg_info_rsp *msg)
2399 {
2400         unsigned int sg_cnt, total_len;
2401         int i, sgi;
2402
2403         sg_cnt = le16_to_cpu(msg->sg_cnt);
2404         if (!sg_cnt || (clt_path->queue_depth % sg_cnt)) {
2405                 rtrs_err(clt_path->clt,
2406                           "Incorrect sg_cnt %d, is not multiple\n",
2407                           sg_cnt);
2408                 return -EINVAL;
2409         }
2410
2411         /*
2412          * Check if IB immediate data size is enough to hold the mem_id and
2413          * the offset inside the memory chunk.
2414          */
2415         if ((ilog2(sg_cnt - 1) + 1) + (ilog2(clt_path->chunk_size - 1) + 1) >
2416             MAX_IMM_PAYL_BITS) {
2417                 rtrs_err(clt_path->clt,
2418                           "RDMA immediate size (%db) not enough to encode %d buffers of size %dB\n",
2419                           MAX_IMM_PAYL_BITS, sg_cnt, clt_path->chunk_size);
2420                 return -EINVAL;
2421         }
2422         total_len = 0;
2423         for (sgi = 0, i = 0; sgi < sg_cnt && i < clt_path->queue_depth; sgi++) {
2424                 const struct rtrs_sg_desc *desc = &msg->desc[sgi];
2425                 u32 len, rkey;
2426                 u64 addr;
2427
2428                 addr = le64_to_cpu(desc->addr);
2429                 rkey = le32_to_cpu(desc->key);
2430                 len  = le32_to_cpu(desc->len);
2431
2432                 total_len += len;
2433
2434                 if (!len || (len % clt_path->chunk_size)) {
2435                         rtrs_err(clt_path->clt, "Incorrect [%d].len %d\n",
2436                                   sgi,
2437                                   len);
2438                         return -EINVAL;
2439                 }
2440                 for ( ; len && i < clt_path->queue_depth; i++) {
2441                         clt_path->rbufs[i].addr = addr;
2442                         clt_path->rbufs[i].rkey = rkey;
2443
2444                         len  -= clt_path->chunk_size;
2445                         addr += clt_path->chunk_size;
2446                 }
2447         }
2448         /* Sanity check */
2449         if (sgi != sg_cnt || i != clt_path->queue_depth) {
2450                 rtrs_err(clt_path->clt,
2451                          "Incorrect sg vector, not fully mapped\n");
2452                 return -EINVAL;
2453         }
2454         if (total_len != clt_path->chunk_size * clt_path->queue_depth) {
2455                 rtrs_err(clt_path->clt, "Incorrect total_len %d\n", total_len);
2456                 return -EINVAL;
2457         }
2458
2459         return 0;
2460 }
2461
2462 static void rtrs_clt_info_rsp_done(struct ib_cq *cq, struct ib_wc *wc)
2463 {
2464         struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context);
2465         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
2466         struct rtrs_msg_info_rsp *msg;
2467         enum rtrs_clt_state state;
2468         struct rtrs_iu *iu;
2469         size_t rx_sz;
2470         int err;
2471
2472         state = RTRS_CLT_CONNECTING_ERR;
2473
2474         WARN_ON(con->c.cid);
2475         iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
2476         if (wc->status != IB_WC_SUCCESS) {
2477                 rtrs_err(clt_path->clt, "Path info response recv failed: %s\n",
2478                           ib_wc_status_msg(wc->status));
2479                 goto out;
2480         }
2481         WARN_ON(wc->opcode != IB_WC_RECV);
2482
2483         if (wc->byte_len < sizeof(*msg)) {
2484                 rtrs_err(clt_path->clt, "Path info response is malformed: size %d\n",
2485                           wc->byte_len);
2486                 goto out;
2487         }
2488         ib_dma_sync_single_for_cpu(clt_path->s.dev->ib_dev, iu->dma_addr,
2489                                    iu->size, DMA_FROM_DEVICE);
2490         msg = iu->buf;
2491         if (le16_to_cpu(msg->type) != RTRS_MSG_INFO_RSP) {
2492                 rtrs_err(clt_path->clt, "Path info response is malformed: type %d\n",
2493                           le16_to_cpu(msg->type));
2494                 goto out;
2495         }
2496         rx_sz  = sizeof(*msg);
2497         rx_sz += sizeof(msg->desc[0]) * le16_to_cpu(msg->sg_cnt);
2498         if (wc->byte_len < rx_sz) {
2499                 rtrs_err(clt_path->clt, "Path info response is malformed: size %d\n",
2500                           wc->byte_len);
2501                 goto out;
2502         }
2503         err = process_info_rsp(clt_path, msg);
2504         if (err)
2505                 goto out;
2506
2507         err = post_recv_path(clt_path);
2508         if (err)
2509                 goto out;
2510
2511         state = RTRS_CLT_CONNECTED;
2512
2513 out:
2514         rtrs_clt_update_wc_stats(con);
2515         rtrs_iu_free(iu, clt_path->s.dev->ib_dev, 1);
2516         rtrs_clt_change_state_get_old(clt_path, state, NULL);
2517 }
2518
2519 static int rtrs_send_path_info(struct rtrs_clt_path *clt_path)
2520 {
2521         struct rtrs_clt_con *usr_con = to_clt_con(clt_path->s.con[0]);
2522         struct rtrs_msg_info_req *msg;
2523         struct rtrs_iu *tx_iu, *rx_iu;
2524         size_t rx_sz;
2525         int err;
2526
2527         rx_sz  = sizeof(struct rtrs_msg_info_rsp);
2528         rx_sz += sizeof(struct rtrs_sg_desc) * clt_path->queue_depth;
2529
2530         tx_iu = rtrs_iu_alloc(1, sizeof(struct rtrs_msg_info_req), GFP_KERNEL,
2531                                clt_path->s.dev->ib_dev, DMA_TO_DEVICE,
2532                                rtrs_clt_info_req_done);
2533         rx_iu = rtrs_iu_alloc(1, rx_sz, GFP_KERNEL, clt_path->s.dev->ib_dev,
2534                                DMA_FROM_DEVICE, rtrs_clt_info_rsp_done);
2535         if (!tx_iu || !rx_iu) {
2536                 err = -ENOMEM;
2537                 goto out;
2538         }
2539         /* Prepare for getting info response */
2540         err = rtrs_iu_post_recv(&usr_con->c, rx_iu);
2541         if (err) {
2542                 rtrs_err(clt_path->clt, "rtrs_iu_post_recv(), err: %d\n", err);
2543                 goto out;
2544         }
2545         rx_iu = NULL;
2546
2547         msg = tx_iu->buf;
2548         msg->type = cpu_to_le16(RTRS_MSG_INFO_REQ);
2549         memcpy(msg->pathname, clt_path->s.sessname, sizeof(msg->pathname));
2550
2551         ib_dma_sync_single_for_device(clt_path->s.dev->ib_dev,
2552                                       tx_iu->dma_addr,
2553                                       tx_iu->size, DMA_TO_DEVICE);
2554
2555         /* Send info request */
2556         err = rtrs_iu_post_send(&usr_con->c, tx_iu, sizeof(*msg), NULL);
2557         if (err) {
2558                 rtrs_err(clt_path->clt, "rtrs_iu_post_send(), err: %d\n", err);
2559                 goto out;
2560         }
2561         tx_iu = NULL;
2562
2563         /* Wait for state change */
2564         wait_event_interruptible_timeout(clt_path->state_wq,
2565                                          clt_path->state != RTRS_CLT_CONNECTING,
2566                                          msecs_to_jiffies(
2567                                                  RTRS_CONNECT_TIMEOUT_MS));
2568         if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED) {
2569                 if (READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTING_ERR)
2570                         err = -ECONNRESET;
2571                 else
2572                         err = -ETIMEDOUT;
2573         }
2574
2575 out:
2576         if (tx_iu)
2577                 rtrs_iu_free(tx_iu, clt_path->s.dev->ib_dev, 1);
2578         if (rx_iu)
2579                 rtrs_iu_free(rx_iu, clt_path->s.dev->ib_dev, 1);
2580         if (err)
2581                 /* If we've never taken async path because of malloc problems */
2582                 rtrs_clt_change_state_get_old(clt_path,
2583                                               RTRS_CLT_CONNECTING_ERR, NULL);
2584
2585         return err;
2586 }
2587
2588 /**
2589  * init_path() - establishes all path connections and does handshake
2590  * @clt_path: client path.
2591  * In case of error full close or reconnect procedure should be taken,
2592  * because reconnect or close async works can be started.
2593  */
2594 static int init_path(struct rtrs_clt_path *clt_path)
2595 {
2596         int err;
2597         char str[NAME_MAX];
2598         struct rtrs_addr path = {
2599                 .src = &clt_path->s.src_addr,
2600                 .dst = &clt_path->s.dst_addr,
2601         };
2602
2603         rtrs_addr_to_str(&path, str, sizeof(str));
2604
2605         mutex_lock(&clt_path->init_mutex);
2606         err = init_conns(clt_path);
2607         if (err) {
2608                 rtrs_err(clt_path->clt,
2609                          "init_conns() failed: err=%d path=%s [%s:%u]\n", err,
2610                          str, clt_path->hca_name, clt_path->hca_port);
2611                 goto out;
2612         }
2613         err = rtrs_send_path_info(clt_path);
2614         if (err) {
2615                 rtrs_err(clt_path->clt,
2616                          "rtrs_send_path_info() failed: err=%d path=%s [%s:%u]\n",
2617                          err, str, clt_path->hca_name, clt_path->hca_port);
2618                 goto out;
2619         }
2620         rtrs_clt_path_up(clt_path);
2621         rtrs_start_hb(&clt_path->s);
2622 out:
2623         mutex_unlock(&clt_path->init_mutex);
2624
2625         return err;
2626 }
2627
2628 static void rtrs_clt_reconnect_work(struct work_struct *work)
2629 {
2630         struct rtrs_clt_path *clt_path;
2631         struct rtrs_clt_sess *clt;
2632         int err;
2633
2634         clt_path = container_of(to_delayed_work(work), struct rtrs_clt_path,
2635                                 reconnect_dwork);
2636         clt = clt_path->clt;
2637
2638         trace_rtrs_clt_reconnect_work(clt_path);
2639
2640         if (READ_ONCE(clt_path->state) != RTRS_CLT_RECONNECTING)
2641                 return;
2642
2643         if (clt_path->reconnect_attempts >= clt->max_reconnect_attempts) {
2644                 /* Close a path completely if max attempts is reached */
2645                 rtrs_clt_close_conns(clt_path, false);
2646                 return;
2647         }
2648         clt_path->reconnect_attempts++;
2649
2650         msleep(RTRS_RECONNECT_BACKOFF);
2651         if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CONNECTING, NULL)) {
2652                 err = init_path(clt_path);
2653                 if (err)
2654                         goto reconnect_again;
2655         }
2656
2657         return;
2658
2659 reconnect_again:
2660         if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_RECONNECTING, NULL)) {
2661                 clt_path->stats->reconnects.fail_cnt++;
2662                 queue_work(rtrs_wq, &clt_path->err_recovery_work);
2663         }
2664 }
2665
2666 static void rtrs_clt_dev_release(struct device *dev)
2667 {
2668         struct rtrs_clt_sess *clt = container_of(dev, struct rtrs_clt_sess,
2669                                                  dev);
2670
2671         mutex_destroy(&clt->paths_ev_mutex);
2672         mutex_destroy(&clt->paths_mutex);
2673         kfree(clt);
2674 }
2675
2676 static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
2677                                   u16 port, size_t pdu_sz, void *priv,
2678                                   void  (*link_ev)(void *priv,
2679                                                    enum rtrs_clt_link_ev ev),
2680                                   unsigned int reconnect_delay_sec,
2681                                   unsigned int max_reconnect_attempts)
2682 {
2683         struct rtrs_clt_sess *clt;
2684         int err;
2685
2686         if (!paths_num || paths_num > MAX_PATHS_NUM)
2687                 return ERR_PTR(-EINVAL);
2688
2689         if (strlen(sessname) >= sizeof(clt->sessname))
2690                 return ERR_PTR(-EINVAL);
2691
2692         clt = kzalloc(sizeof(*clt), GFP_KERNEL);
2693         if (!clt)
2694                 return ERR_PTR(-ENOMEM);
2695
2696         clt->pcpu_path = alloc_percpu(typeof(*clt->pcpu_path));
2697         if (!clt->pcpu_path) {
2698                 kfree(clt);
2699                 return ERR_PTR(-ENOMEM);
2700         }
2701
2702         clt->dev.class = &rtrs_clt_dev_class;
2703         clt->dev.release = rtrs_clt_dev_release;
2704         uuid_gen(&clt->paths_uuid);
2705         INIT_LIST_HEAD_RCU(&clt->paths_list);
2706         clt->paths_num = paths_num;
2707         clt->paths_up = MAX_PATHS_NUM;
2708         clt->port = port;
2709         clt->pdu_sz = pdu_sz;
2710         clt->max_segments = RTRS_MAX_SEGMENTS;
2711         clt->reconnect_delay_sec = reconnect_delay_sec;
2712         clt->max_reconnect_attempts = max_reconnect_attempts;
2713         clt->priv = priv;
2714         clt->link_ev = link_ev;
2715         clt->mp_policy = MP_POLICY_MIN_INFLIGHT;
2716         strscpy(clt->sessname, sessname, sizeof(clt->sessname));
2717         init_waitqueue_head(&clt->permits_wait);
2718         mutex_init(&clt->paths_ev_mutex);
2719         mutex_init(&clt->paths_mutex);
2720         device_initialize(&clt->dev);
2721
2722         err = dev_set_name(&clt->dev, "%s", sessname);
2723         if (err)
2724                 goto err_put;
2725
2726         /*
2727          * Suppress user space notification until
2728          * sysfs files are created
2729          */
2730         dev_set_uevent_suppress(&clt->dev, true);
2731         err = device_add(&clt->dev);
2732         if (err)
2733                 goto err_put;
2734
2735         clt->kobj_paths = kobject_create_and_add("paths", &clt->dev.kobj);
2736         if (!clt->kobj_paths) {
2737                 err = -ENOMEM;
2738                 goto err_del;
2739         }
2740         err = rtrs_clt_create_sysfs_root_files(clt);
2741         if (err) {
2742                 kobject_del(clt->kobj_paths);
2743                 kobject_put(clt->kobj_paths);
2744                 goto err_del;
2745         }
2746         dev_set_uevent_suppress(&clt->dev, false);
2747         kobject_uevent(&clt->dev.kobj, KOBJ_ADD);
2748
2749         return clt;
2750 err_del:
2751         device_del(&clt->dev);
2752 err_put:
2753         free_percpu(clt->pcpu_path);
2754         put_device(&clt->dev);
2755         return ERR_PTR(err);
2756 }
2757
2758 static void free_clt(struct rtrs_clt_sess *clt)
2759 {
2760         free_percpu(clt->pcpu_path);
2761
2762         /*
2763          * release callback will free clt and destroy mutexes in last put
2764          */
2765         device_unregister(&clt->dev);
2766 }
2767
2768 /**
2769  * rtrs_clt_open() - Open a path to an RTRS server
2770  * @ops: holds the link event callback and the private pointer.
2771  * @pathname: name of the path to an RTRS server
2772  * @paths: Paths to be established defined by their src and dst addresses
2773  * @paths_num: Number of elements in the @paths array
2774  * @port: port to be used by the RTRS session
2775  * @pdu_sz: Size of extra payload which can be accessed after permit allocation.
2776  * @reconnect_delay_sec: time between reconnect tries
2777  * @max_reconnect_attempts: Number of times to reconnect on error before giving
2778  *                          up, 0 for * disabled, -1 for forever
2779  * @nr_poll_queues: number of polling mode connection using IB_POLL_DIRECT flag
2780  *
2781  * Starts session establishment with the rtrs_server. The function can block
2782  * up to ~2000ms before it returns.
2783  *
2784  * Return a valid pointer on success otherwise PTR_ERR.
2785  */
2786 struct rtrs_clt_sess *rtrs_clt_open(struct rtrs_clt_ops *ops,
2787                                  const char *pathname,
2788                                  const struct rtrs_addr *paths,
2789                                  size_t paths_num, u16 port,
2790                                  size_t pdu_sz, u8 reconnect_delay_sec,
2791                                  s16 max_reconnect_attempts, u32 nr_poll_queues)
2792 {
2793         struct rtrs_clt_path *clt_path, *tmp;
2794         struct rtrs_clt_sess *clt;
2795         int err, i;
2796
2797         if (strchr(pathname, '/') || strchr(pathname, '.')) {
2798                 pr_err("pathname cannot contain / and .\n");
2799                 err = -EINVAL;
2800                 goto out;
2801         }
2802
2803         clt = alloc_clt(pathname, paths_num, port, pdu_sz, ops->priv,
2804                         ops->link_ev,
2805                         reconnect_delay_sec,
2806                         max_reconnect_attempts);
2807         if (IS_ERR(clt)) {
2808                 err = PTR_ERR(clt);
2809                 goto out;
2810         }
2811         for (i = 0; i < paths_num; i++) {
2812                 struct rtrs_clt_path *clt_path;
2813
2814                 clt_path = alloc_path(clt, &paths[i], nr_cpu_ids,
2815                                   nr_poll_queues);
2816                 if (IS_ERR(clt_path)) {
2817                         err = PTR_ERR(clt_path);
2818                         goto close_all_path;
2819                 }
2820                 if (!i)
2821                         clt_path->for_new_clt = 1;
2822                 list_add_tail_rcu(&clt_path->s.entry, &clt->paths_list);
2823
2824                 err = init_path(clt_path);
2825                 if (err) {
2826                         list_del_rcu(&clt_path->s.entry);
2827                         rtrs_clt_close_conns(clt_path, true);
2828                         free_percpu(clt_path->stats->pcpu_stats);
2829                         kfree(clt_path->stats);
2830                         free_path(clt_path);
2831                         goto close_all_path;
2832                 }
2833
2834                 err = rtrs_clt_create_path_files(clt_path);
2835                 if (err) {
2836                         list_del_rcu(&clt_path->s.entry);
2837                         rtrs_clt_close_conns(clt_path, true);
2838                         free_percpu(clt_path->stats->pcpu_stats);
2839                         kfree(clt_path->stats);
2840                         free_path(clt_path);
2841                         goto close_all_path;
2842                 }
2843         }
2844         err = alloc_permits(clt);
2845         if (err)
2846                 goto close_all_path;
2847
2848         return clt;
2849
2850 close_all_path:
2851         list_for_each_entry_safe(clt_path, tmp, &clt->paths_list, s.entry) {
2852                 rtrs_clt_destroy_path_files(clt_path, NULL);
2853                 rtrs_clt_close_conns(clt_path, true);
2854                 kobject_put(&clt_path->kobj);
2855         }
2856         rtrs_clt_destroy_sysfs_root(clt);
2857         free_clt(clt);
2858
2859 out:
2860         return ERR_PTR(err);
2861 }
2862 EXPORT_SYMBOL(rtrs_clt_open);
2863
2864 /**
2865  * rtrs_clt_close() - Close a path
2866  * @clt: Session handle. Session is freed upon return.
2867  */
2868 void rtrs_clt_close(struct rtrs_clt_sess *clt)
2869 {
2870         struct rtrs_clt_path *clt_path, *tmp;
2871
2872         /* Firstly forbid sysfs access */
2873         rtrs_clt_destroy_sysfs_root(clt);
2874
2875         /* Now it is safe to iterate over all paths without locks */
2876         list_for_each_entry_safe(clt_path, tmp, &clt->paths_list, s.entry) {
2877                 rtrs_clt_close_conns(clt_path, true);
2878                 rtrs_clt_destroy_path_files(clt_path, NULL);
2879                 kobject_put(&clt_path->kobj);
2880         }
2881         free_permits(clt);
2882         free_clt(clt);
2883 }
2884 EXPORT_SYMBOL(rtrs_clt_close);
2885
2886 int rtrs_clt_reconnect_from_sysfs(struct rtrs_clt_path *clt_path)
2887 {
2888         enum rtrs_clt_state old_state;
2889         int err = -EBUSY;
2890         bool changed;
2891
2892         changed = rtrs_clt_change_state_get_old(clt_path,
2893                                                  RTRS_CLT_RECONNECTING,
2894                                                  &old_state);
2895         if (changed) {
2896                 clt_path->reconnect_attempts = 0;
2897                 rtrs_clt_stop_and_destroy_conns(clt_path);
2898                 queue_delayed_work(rtrs_wq, &clt_path->reconnect_dwork, 0);
2899         }
2900         if (changed || old_state == RTRS_CLT_RECONNECTING) {
2901                 /*
2902                  * flush_delayed_work() queues pending work for immediate
2903                  * execution, so do the flush if we have queued something
2904                  * right now or work is pending.
2905                  */
2906                 flush_delayed_work(&clt_path->reconnect_dwork);
2907                 err = (READ_ONCE(clt_path->state) ==
2908                        RTRS_CLT_CONNECTED ? 0 : -ENOTCONN);
2909         }
2910
2911         return err;
2912 }
2913
2914 int rtrs_clt_remove_path_from_sysfs(struct rtrs_clt_path *clt_path,
2915                                      const struct attribute *sysfs_self)
2916 {
2917         enum rtrs_clt_state old_state;
2918         bool changed;
2919
2920         /*
2921          * Continue stopping path till state was changed to DEAD or
2922          * state was observed as DEAD:
2923          * 1. State was changed to DEAD - we were fast and nobody
2924          *    invoked rtrs_clt_reconnect(), which can again start
2925          *    reconnecting.
2926          * 2. State was observed as DEAD - we have someone in parallel
2927          *    removing the path.
2928          */
2929         do {
2930                 rtrs_clt_close_conns(clt_path, true);
2931                 changed = rtrs_clt_change_state_get_old(clt_path,
2932                                                         RTRS_CLT_DEAD,
2933                                                         &old_state);
2934         } while (!changed && old_state != RTRS_CLT_DEAD);
2935
2936         if (changed) {
2937                 rtrs_clt_remove_path_from_arr(clt_path);
2938                 rtrs_clt_destroy_path_files(clt_path, sysfs_self);
2939                 kobject_put(&clt_path->kobj);
2940         }
2941
2942         return 0;
2943 }
2944
2945 void rtrs_clt_set_max_reconnect_attempts(struct rtrs_clt_sess *clt, int value)
2946 {
2947         clt->max_reconnect_attempts = (unsigned int)value;
2948 }
2949
2950 int rtrs_clt_get_max_reconnect_attempts(const struct rtrs_clt_sess *clt)
2951 {
2952         return (int)clt->max_reconnect_attempts;
2953 }
2954
2955 /**
2956  * rtrs_clt_request() - Request data transfer to/from server via RDMA.
2957  *
2958  * @dir:        READ/WRITE
2959  * @ops:        callback function to be called as confirmation, and the pointer.
2960  * @clt:        Session
2961  * @permit:     Preallocated permit
2962  * @vec:        Message that is sent to server together with the request.
2963  *              Sum of len of all @vec elements limited to <= IO_MSG_SIZE.
2964  *              Since the msg is copied internally it can be allocated on stack.
2965  * @nr:         Number of elements in @vec.
2966  * @data_len:   length of data sent to/from server
2967  * @sg:         Pages to be sent/received to/from server.
2968  * @sg_cnt:     Number of elements in the @sg
2969  *
2970  * Return:
2971  * 0:           Success
2972  * <0:          Error
2973  *
2974  * On dir=READ rtrs client will request a data transfer from Server to client.
2975  * The data that the server will respond with will be stored in @sg when
2976  * the user receives an %RTRS_CLT_RDMA_EV_RDMA_REQUEST_WRITE_COMPL event.
2977  * On dir=WRITE rtrs client will rdma write data in sg to server side.
2978  */
2979 int rtrs_clt_request(int dir, struct rtrs_clt_req_ops *ops,
2980                      struct rtrs_clt_sess *clt, struct rtrs_permit *permit,
2981                      const struct kvec *vec, size_t nr, size_t data_len,
2982                      struct scatterlist *sg, unsigned int sg_cnt)
2983 {
2984         struct rtrs_clt_io_req *req;
2985         struct rtrs_clt_path *clt_path;
2986
2987         enum dma_data_direction dma_dir;
2988         int err = -ECONNABORTED, i;
2989         size_t usr_len, hdr_len;
2990         struct path_it it;
2991
2992         /* Get kvec length */
2993         for (i = 0, usr_len = 0; i < nr; i++)
2994                 usr_len += vec[i].iov_len;
2995
2996         if (dir == READ) {
2997                 hdr_len = sizeof(struct rtrs_msg_rdma_read) +
2998                           sg_cnt * sizeof(struct rtrs_sg_desc);
2999                 dma_dir = DMA_FROM_DEVICE;
3000         } else {
3001                 hdr_len = sizeof(struct rtrs_msg_rdma_write);
3002                 dma_dir = DMA_TO_DEVICE;
3003         }
3004
3005         rcu_read_lock();
3006         for (path_it_init(&it, clt);
3007              (clt_path = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) {
3008                 if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
3009                         continue;
3010
3011                 if (usr_len + hdr_len > clt_path->max_hdr_size) {
3012                         rtrs_wrn_rl(clt_path->clt,
3013                                      "%s request failed, user message size is %zu and header length %zu, but max size is %u\n",
3014                                      dir == READ ? "Read" : "Write",
3015                                      usr_len, hdr_len, clt_path->max_hdr_size);
3016                         err = -EMSGSIZE;
3017                         break;
3018                 }
3019                 req = rtrs_clt_get_req(clt_path, ops->conf_fn, permit, ops->priv,
3020                                        vec, usr_len, sg, sg_cnt, data_len,
3021                                        dma_dir);
3022                 if (dir == READ)
3023                         err = rtrs_clt_read_req(req);
3024                 else
3025                         err = rtrs_clt_write_req(req);
3026                 if (err) {
3027                         req->in_use = false;
3028                         continue;
3029                 }
3030                 /* Success path */
3031                 break;
3032         }
3033         path_it_deinit(&it);
3034         rcu_read_unlock();
3035
3036         return err;
3037 }
3038 EXPORT_SYMBOL(rtrs_clt_request);
3039
3040 int rtrs_clt_rdma_cq_direct(struct rtrs_clt_sess *clt, unsigned int index)
3041 {
3042         /* If no path, return -1 for block layer not to try again */
3043         int cnt = -1;
3044         struct rtrs_con *con;
3045         struct rtrs_clt_path *clt_path;
3046         struct path_it it;
3047
3048         rcu_read_lock();
3049         for (path_it_init(&it, clt);
3050              (clt_path = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) {
3051                 if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
3052                         continue;
3053
3054                 con = clt_path->s.con[index + 1];
3055                 cnt = ib_process_cq_direct(con->cq, -1);
3056                 if (cnt)
3057                         break;
3058         }
3059         path_it_deinit(&it);
3060         rcu_read_unlock();
3061
3062         return cnt;
3063 }
3064 EXPORT_SYMBOL(rtrs_clt_rdma_cq_direct);
3065
3066 /**
3067  * rtrs_clt_query() - queries RTRS session attributes
3068  *@clt: session pointer
3069  *@attr: query results for session attributes.
3070  * Returns:
3071  *    0 on success
3072  *    -ECOMM            no connection to the server
3073  */
3074 int rtrs_clt_query(struct rtrs_clt_sess *clt, struct rtrs_attrs *attr)
3075 {
3076         if (!rtrs_clt_is_connected(clt))
3077                 return -ECOMM;
3078
3079         attr->queue_depth      = clt->queue_depth;
3080         attr->max_segments     = clt->max_segments;
3081         /* Cap max_io_size to min of remote buffer size and the fr pages */
3082         attr->max_io_size = min_t(int, clt->max_io_size,
3083                                   clt->max_segments * SZ_4K);
3084
3085         return 0;
3086 }
3087 EXPORT_SYMBOL(rtrs_clt_query);
3088
3089 int rtrs_clt_create_path_from_sysfs(struct rtrs_clt_sess *clt,
3090                                      struct rtrs_addr *addr)
3091 {
3092         struct rtrs_clt_path *clt_path;
3093         int err;
3094
3095         clt_path = alloc_path(clt, addr, nr_cpu_ids, 0);
3096         if (IS_ERR(clt_path))
3097                 return PTR_ERR(clt_path);
3098
3099         mutex_lock(&clt->paths_mutex);
3100         if (clt->paths_num == 0) {
3101                 /*
3102                  * When all the paths are removed for a session,
3103                  * the addition of the first path is like a new session for
3104                  * the storage server
3105                  */
3106                 clt_path->for_new_clt = 1;
3107         }
3108
3109         mutex_unlock(&clt->paths_mutex);
3110
3111         /*
3112          * It is totally safe to add path in CONNECTING state: coming
3113          * IO will never grab it.  Also it is very important to add
3114          * path before init, since init fires LINK_CONNECTED event.
3115          */
3116         rtrs_clt_add_path_to_arr(clt_path);
3117
3118         err = init_path(clt_path);
3119         if (err)
3120                 goto close_path;
3121
3122         err = rtrs_clt_create_path_files(clt_path);
3123         if (err)
3124                 goto close_path;
3125
3126         return 0;
3127
3128 close_path:
3129         rtrs_clt_remove_path_from_arr(clt_path);
3130         rtrs_clt_close_conns(clt_path, true);
3131         free_percpu(clt_path->stats->pcpu_stats);
3132         kfree(clt_path->stats);
3133         free_path(clt_path);
3134
3135         return err;
3136 }
3137
3138 static int rtrs_clt_ib_dev_init(struct rtrs_ib_dev *dev)
3139 {
3140         if (!(dev->ib_dev->attrs.device_cap_flags &
3141               IB_DEVICE_MEM_MGT_EXTENSIONS)) {
3142                 pr_err("Memory registrations not supported.\n");
3143                 return -ENOTSUPP;
3144         }
3145
3146         return 0;
3147 }
3148
3149 static const struct rtrs_rdma_dev_pd_ops dev_pd_ops = {
3150         .init = rtrs_clt_ib_dev_init
3151 };
3152
3153 static int __init rtrs_client_init(void)
3154 {
3155         int ret = 0;
3156
3157         rtrs_rdma_dev_pd_init(0, &dev_pd);
3158         ret = class_register(&rtrs_clt_dev_class);
3159         if (ret) {
3160                 pr_err("Failed to create rtrs-client dev class\n");
3161                 return ret;
3162         }
3163         rtrs_wq = alloc_workqueue("rtrs_client_wq", 0, 0);
3164         if (!rtrs_wq) {
3165                 class_unregister(&rtrs_clt_dev_class);
3166                 return -ENOMEM;
3167         }
3168
3169         return 0;
3170 }
3171
3172 static void __exit rtrs_client_exit(void)
3173 {
3174         destroy_workqueue(rtrs_wq);
3175         class_unregister(&rtrs_clt_dev_class);
3176         rtrs_rdma_dev_pd_deinit(&dev_pd);
3177 }
3178
3179 module_init(rtrs_client_init);
3180 module_exit(rtrs_client_exit);