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
  20 #define RTRS_CONNECT_TIMEOUT_MS 30000
  21 /*
  22  * Wait a bit before trying to reconnect after a failure
  23  * in order to give server time to finish clean up which
  24  * leads to "false positives" failed reconnect attempts
  25  */
  26 #define RTRS_RECONNECT_BACKOFF 1000
  27 /*
  28  * Wait for additional random time between 0 and 8 seconds
  29  * before starting to reconnect to avoid clients reconnecting
  30  * all at once in case of a major network outage
  31  */
  32 #define RTRS_RECONNECT_SEED 8
  33
  34 #define FIRST_CONN 0x01
  35 /* limit to 128 * 4k = 512k max IO */
  36 #define RTRS_MAX_SEGMENTS          128
  37
  38 MODULE_DESCRIPTION("RDMA Transport Client");
  39 MODULE_LICENSE("GPL");
  40
  41 static const struct rtrs_rdma_dev_pd_ops dev_pd_ops;
  42 static struct rtrs_rdma_dev_pd dev_pd = {
  43         .ops = &dev_pd_ops
  44 };
  45
  46 static struct workqueue_struct *rtrs_wq;
  47 static struct class *rtrs_clt_dev_class;
  48
  49 static inline bool rtrs_clt_is_connected(const struct rtrs_clt_sess *clt)
  50 {
  51         struct rtrs_clt_path *clt_path;
  52         bool connected = false;
  53
  54         rcu_read_lock();
  55         list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry)
  56                 connected |= READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTED;
  57         rcu_read_unlock();
  58
  59         return connected;
  60 }
  61
  62 static struct rtrs_permit *
  63 __rtrs_get_permit(struct rtrs_clt_sess *clt, enum rtrs_clt_con_type con_type)
  64 {
  65         size_t max_depth = clt->queue_depth;
  66         struct rtrs_permit *permit;
  67         int bit;
  68
  69         /*
  70          * Adapted from null_blk get_tag(). Callers from different cpus may
  71          * grab the same bit, since find_first_zero_bit is not atomic.
  72          * But then the test_and_set_bit_lock will fail for all the
  73          * callers but one, so that they will loop again.
  74          * This way an explicit spinlock is not required.
  75          */
  76         do {
  77                 bit = find_first_zero_bit(clt->permits_map, max_depth);
  78                 if (bit >= max_depth)
  79                         return NULL;
  80         } while (test_and_set_bit_lock(bit, clt->permits_map));
  81
  82         permit = get_permit(clt, bit);
  83         WARN_ON(permit->mem_id != bit);
  84         permit->cpu_id = raw_smp_processor_id();
  85         permit->con_type = con_type;
  86
  87         return permit;
  88 }
  89
  90 static inline void __rtrs_put_permit(struct rtrs_clt_sess *clt,
  91                                       struct rtrs_permit *permit)
  92 {
  93         clear_bit_unlock(permit->mem_id, clt->permits_map);
  94 }
  95
  96 /**
  97  * rtrs_clt_get_permit() - allocates permit for future RDMA operation
  98  * @clt:        Current session
  99  * @con_type:   Type of connection to use with the permit
 100  * @can_wait:   Wait type
 101  *
 102  * Description:
 103  *    Allocates permit for the following RDMA operation.  Permit is used
 104  *    to preallocate all resources and to propagate memory pressure
 105  *    up earlier.
 106  *
 107  * Context:
 108  *    Can sleep if @wait == RTRS_PERMIT_WAIT
 109  */
 110 struct rtrs_permit *rtrs_clt_get_permit(struct rtrs_clt_sess *clt,
 111                                           enum rtrs_clt_con_type con_type,
 112                                           enum wait_type can_wait)
 113 {
 114         struct rtrs_permit *permit;
 115         DEFINE_WAIT(wait);
 116
 117         permit = __rtrs_get_permit(clt, con_type);
 118         if (permit || !can_wait)
 119                 return permit;
 120
 121         do {
 122                 prepare_to_wait(&clt->permits_wait, &wait,
 123                                 TASK_UNINTERRUPTIBLE);
 124                 permit = __rtrs_get_permit(clt, con_type);
 125                 if (permit)
 126                         break;
 127
 128                 io_schedule();
 129         } while (1);
 130
 131         finish_wait(&clt->permits_wait, &wait);
 132
 133         return permit;
 134 }
 135 EXPORT_SYMBOL(rtrs_clt_get_permit);
 136
 137 /**
 138  * rtrs_clt_put_permit() - puts allocated permit
 139  * @clt:        Current session
 140  * @permit:     Permit to be freed
 141  *
 142  * Context:
 143  *    Does not matter
 144  */
 145 void rtrs_clt_put_permit(struct rtrs_clt_sess *clt,
 146                          struct rtrs_permit *permit)
 147 {
 148         if (WARN_ON(!test_bit(permit->mem_id, clt->permits_map)))
 149                 return;
 150
 151         __rtrs_put_permit(clt, permit);
 152
 153         /*
 154          * rtrs_clt_get_permit() adds itself to the &clt->permits_wait list
 155          * before calling schedule(). So if rtrs_clt_get_permit() is sleeping
 156          * it must have added itself to &clt->permits_wait before
 157          * __rtrs_put_permit() finished.
 158          * Hence it is safe to guard wake_up() with a waitqueue_active() test.
 159          */
 160         if (waitqueue_active(&clt->permits_wait))
 161                 wake_up(&clt->permits_wait);
 162 }
 163 EXPORT_SYMBOL(rtrs_clt_put_permit);
 164
 165 /**
 166  * rtrs_permit_to_clt_con() - returns RDMA connection pointer by the permit
 167  * @clt_path: client path pointer
 168  * @permit: permit for the allocation of the RDMA buffer
 169  * Note:
 170  *     IO connection starts from 1.
 171  *     0 connection is for user messages.
 172  */
 173 static
 174 struct rtrs_clt_con *rtrs_permit_to_clt_con(struct rtrs_clt_path *clt_path,
 175                                             struct rtrs_permit *permit)
 176 {
 177         int id = 0;
 178
 179         if (permit->con_type == RTRS_IO_CON)
 180                 id = (permit->cpu_id % (clt_path->s.irq_con_num - 1)) + 1;
 181
 182         return to_clt_con(clt_path->s.con[id]);
 183 }
 184
 185 /**
 186  * rtrs_clt_change_state() - change the session state through session state
 187  * machine.
 188  *
 189  * @clt_path: client path to change the state of.
 190  * @new_state: state to change to.
 191  *
 192  * returns true if sess's state is changed to new state, otherwise return false.
 193  *
 194  * Locks:
 195  * state_wq lock must be hold.
 196  */
 197 static bool rtrs_clt_change_state(struct rtrs_clt_path *clt_path,
 198                                      enum rtrs_clt_state new_state)
 199 {
 200         enum rtrs_clt_state old_state;
 201         bool changed = false;
 202
 203         lockdep_assert_held(&clt_path->state_wq.lock);
 204
 205         old_state = clt_path->state;
 206         switch (new_state) {
 207         case RTRS_CLT_CONNECTING:
 208                 switch (old_state) {
 209                 case RTRS_CLT_RECONNECTING:
 210                         changed = true;
 211                         fallthrough;
 212                 default:
 213                         break;
 214                 }
 215                 break;
 216         case RTRS_CLT_RECONNECTING:
 217                 switch (old_state) {
 218                 case RTRS_CLT_CONNECTED:
 219                 case RTRS_CLT_CONNECTING_ERR:
 220                 case RTRS_CLT_CLOSED:
 221                         changed = true;
 222                         fallthrough;
 223                 default:
 224                         break;
 225                 }
 226                 break;
 227         case RTRS_CLT_CONNECTED:
 228                 switch (old_state) {
 229                 case RTRS_CLT_CONNECTING:
 230                         changed = true;
 231                         fallthrough;
 232                 default:
 233                         break;
 234                 }
 235                 break;
 236         case RTRS_CLT_CONNECTING_ERR:
 237                 switch (old_state) {
 238                 case RTRS_CLT_CONNECTING:
 239                         changed = true;
 240                         fallthrough;
 241                 default:
 242                         break;
 243                 }
 244                 break;
 245         case RTRS_CLT_CLOSING:
 246                 switch (old_state) {
 247                 case RTRS_CLT_CONNECTING:
 248                 case RTRS_CLT_CONNECTING_ERR:
 249                 case RTRS_CLT_RECONNECTING:
 250                 case RTRS_CLT_CONNECTED:
 251                         changed = true;
 252                         fallthrough;
 253                 default:
 254                         break;
 255                 }
 256                 break;
 257         case RTRS_CLT_CLOSED:
 258                 switch (old_state) {
 259                 case RTRS_CLT_CLOSING:
 260                         changed = true;
 261                         fallthrough;
 262                 default:
 263                         break;
 264                 }
 265                 break;
 266         case RTRS_CLT_DEAD:
 267                 switch (old_state) {
 268                 case RTRS_CLT_CLOSED:
 269                         changed = true;
 270                         fallthrough;
 271                 default:
 272                         break;
 273                 }
 274                 break;
 275         default:
 276                 break;
 277         }
 278         if (changed) {
 279                 clt_path->state = new_state;
 280                 wake_up_locked(&clt_path->state_wq);
 281         }
 282
 283         return changed;
 284 }
 285
 286 static bool rtrs_clt_change_state_from_to(struct rtrs_clt_path *clt_path,
 287                                            enum rtrs_clt_state old_state,
 288                                            enum rtrs_clt_state new_state)
 289 {
 290         bool changed = false;
 291
 292         spin_lock_irq(&clt_path->state_wq.lock);
 293         if (clt_path->state == old_state)
 294                 changed = rtrs_clt_change_state(clt_path, new_state);
 295         spin_unlock_irq(&clt_path->state_wq.lock);
 296
 297         return changed;
 298 }
 299
 300 static void rtrs_rdma_error_recovery(struct rtrs_clt_con *con)
 301 {
 302         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
 303
 304         if (rtrs_clt_change_state_from_to(clt_path,
 305                                            RTRS_CLT_CONNECTED,
 306                                            RTRS_CLT_RECONNECTING)) {
 307                 struct rtrs_clt_sess *clt = clt_path->clt;
 308                 unsigned int delay_ms;
 309
 310                 /*
 311                  * Normal scenario, reconnect if we were successfully connected
 312                  */
 313                 delay_ms = clt->reconnect_delay_sec * 1000;
 314                 queue_delayed_work(rtrs_wq, &clt_path->reconnect_dwork,
 315                                    msecs_to_jiffies(delay_ms +
 316                                                     prandom_u32() % RTRS_RECONNECT_SEED));
 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  * list_next_or_null_rr_rcu - get next list element in round-robin fashion.
 753  * @head:       the head for the list.
 754  * @ptr:        the list head to take the next element from.
 755  * @type:       the type of the struct this is embedded in.
 756  * @memb:       the name of the list_head within the struct.
 757  *
 758  * Next element returned in round-robin fashion, i.e. head will be skipped,
 759  * but if list is observed as empty, NULL will be returned.
 760  *
 761  * This primitive may safely run concurrently with the _rcu list-mutation
 762  * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
 763  */
 764 #define list_next_or_null_rr_rcu(head, ptr, type, memb) \
 765 ({ \
 766         list_next_or_null_rcu(head, ptr, type, memb) ?: \
 767                 list_next_or_null_rcu(head, READ_ONCE((ptr)->next), \
 768                                       type, memb); \
 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 = list_next_or_null_rr_rcu(&clt->paths_list,
 801                                                 &path->s.entry,
 802                                                 typeof(*path),
 803                                                 s.entry);
 804         rcu_assign_pointer(*ppcpu_path, path);
 805
 806         return path;
 807 }
 808
 809 /**
 810  * get_next_path_min_inflight() - Returns path with minimal inflight count.
 811  * @it: the path pointer
 812  *
 813  * Related to @MP_POLICY_MIN_INFLIGHT
 814  *
 815  * Locks:
 816  *    rcu_read_lock() must be hold.
 817  */
 818 static struct rtrs_clt_path *get_next_path_min_inflight(struct path_it *it)
 819 {
 820         struct rtrs_clt_path *min_path = NULL;
 821         struct rtrs_clt_sess *clt = it->clt;
 822         struct rtrs_clt_path *clt_path;
 823         int min_inflight = INT_MAX;
 824         int inflight;
 825
 826         list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) {
 827                 if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
 828                         continue;
 829
 830                 if (!list_empty(raw_cpu_ptr(clt_path->mp_skip_entry)))
 831                         continue;
 832
 833                 inflight = atomic_read(&clt_path->stats->inflight);
 834
 835                 if (inflight < min_inflight) {
 836                         min_inflight = inflight;
 837                         min_path = clt_path;
 838                 }
 839         }
 840
 841         /*
 842          * add the path to the skip list, so that next time we can get
 843          * a different one
 844          */
 845         if (min_path)
 846                 list_add(raw_cpu_ptr(min_path->mp_skip_entry), &it->skip_list);
 847
 848         return min_path;
 849 }
 850
 851 /**
 852  * get_next_path_min_latency() - Returns path with minimal latency.
 853  * @it: the path pointer
 854  *
 855  * Return: a path with the lowest latency or NULL if all paths are tried
 856  *
 857  * Locks:
 858  *    rcu_read_lock() must be hold.
 859  *
 860  * Related to @MP_POLICY_MIN_LATENCY
 861  *
 862  * This DOES skip an already-tried path.
 863  * There is a skip-list to skip a path if the path has tried but failed.
 864  * It will try the minimum latency path and then the second minimum latency
 865  * path and so on. Finally it will return NULL if all paths are tried.
 866  * Therefore the caller MUST check the returned
 867  * path is NULL and trigger the IO error.
 868  */
 869 static struct rtrs_clt_path *get_next_path_min_latency(struct path_it *it)
 870 {
 871         struct rtrs_clt_path *min_path = NULL;
 872         struct rtrs_clt_sess *clt = it->clt;
 873         struct rtrs_clt_path *clt_path;
 874         ktime_t min_latency = KTIME_MAX;
 875         ktime_t latency;
 876
 877         list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) {
 878                 if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
 879                         continue;
 880
 881                 if (!list_empty(raw_cpu_ptr(clt_path->mp_skip_entry)))
 882                         continue;
 883
 884                 latency = clt_path->s.hb_cur_latency;
 885
 886                 if (latency < min_latency) {
 887                         min_latency = latency;
 888                         min_path = clt_path;
 889                 }
 890         }
 891
 892         /*
 893          * add the path to the skip list, so that next time we can get
 894          * a different one
 895          */
 896         if (min_path)
 897                 list_add(raw_cpu_ptr(min_path->mp_skip_entry), &it->skip_list);
 898
 899         return min_path;
 900 }
 901
 902 static inline void path_it_init(struct path_it *it, struct rtrs_clt_sess *clt)
 903 {
 904         INIT_LIST_HEAD(&it->skip_list);
 905         it->clt = clt;
 906         it->i = 0;
 907
 908         if (clt->mp_policy == MP_POLICY_RR)
 909                 it->next_path = get_next_path_rr;
 910         else if (clt->mp_policy == MP_POLICY_MIN_INFLIGHT)
 911                 it->next_path = get_next_path_min_inflight;
 912         else
 913                 it->next_path = get_next_path_min_latency;
 914 }
 915
 916 static inline void path_it_deinit(struct path_it *it)
 917 {
 918         struct list_head *skip, *tmp;
 919         /*
 920          * The skip_list is used only for the MIN_INFLIGHT policy.
 921          * We need to remove paths from it, so that next IO can insert
 922          * paths (->mp_skip_entry) into a skip_list again.
 923          */
 924         list_for_each_safe(skip, tmp, &it->skip_list)
 925                 list_del_init(skip);
 926 }
 927
 928 /**
 929  * rtrs_clt_init_req() - Initialize an rtrs_clt_io_req holding information
 930  * about an inflight IO.
 931  * The user buffer holding user control message (not data) is copied into
 932  * the corresponding buffer of rtrs_iu (req->iu->buf), which later on will
 933  * also hold the control message of rtrs.
 934  * @req: an io request holding information about IO.
 935  * @clt_path: client path
 936  * @conf: conformation callback function to notify upper layer.
 937  * @permit: permit for allocation of RDMA remote buffer
 938  * @priv: private pointer
 939  * @vec: kernel vector containing control message
 940  * @usr_len: length of the user message
 941  * @sg: scater list for IO data
 942  * @sg_cnt: number of scater list entries
 943  * @data_len: length of the IO data
 944  * @dir: direction of the IO.
 945  */
 946 static void rtrs_clt_init_req(struct rtrs_clt_io_req *req,
 947                               struct rtrs_clt_path *clt_path,
 948                               void (*conf)(void *priv, int errno),
 949                               struct rtrs_permit *permit, void *priv,
 950                               const struct kvec *vec, size_t usr_len,
 951                               struct scatterlist *sg, size_t sg_cnt,
 952                               size_t data_len, int dir)
 953 {
 954         struct iov_iter iter;
 955         size_t len;
 956
 957         req->permit = permit;
 958         req->in_use = true;
 959         req->usr_len = usr_len;
 960         req->data_len = data_len;
 961         req->sglist = sg;
 962         req->sg_cnt = sg_cnt;
 963         req->priv = priv;
 964         req->dir = dir;
 965         req->con = rtrs_permit_to_clt_con(clt_path, permit);
 966         req->conf = conf;
 967         req->need_inv = false;
 968         req->need_inv_comp = false;
 969         req->inv_errno = 0;
 970         refcount_set(&req->ref, 1);
 971         req->mp_policy = clt_path->clt->mp_policy;
 972
 973         iov_iter_kvec(&iter, READ, vec, 1, usr_len);
 974         len = _copy_from_iter(req->iu->buf, usr_len, &iter);
 975         WARN_ON(len != usr_len);
 976
 977         reinit_completion(&req->inv_comp);
 978 }
 979
 980 static struct rtrs_clt_io_req *
 981 rtrs_clt_get_req(struct rtrs_clt_path *clt_path,
 982                  void (*conf)(void *priv, int errno),
 983                  struct rtrs_permit *permit, void *priv,
 984                  const struct kvec *vec, size_t usr_len,
 985                  struct scatterlist *sg, size_t sg_cnt,
 986                  size_t data_len, int dir)
 987 {
 988         struct rtrs_clt_io_req *req;
 989
 990         req = &clt_path->reqs[permit->mem_id];
 991         rtrs_clt_init_req(req, clt_path, conf, permit, priv, vec, usr_len,
 992                            sg, sg_cnt, data_len, dir);
 993         return req;
 994 }
 995
 996 static struct rtrs_clt_io_req *
 997 rtrs_clt_get_copy_req(struct rtrs_clt_path *alive_path,
 998                        struct rtrs_clt_io_req *fail_req)
 999 {
1000         struct rtrs_clt_io_req *req;
1001         struct kvec vec = {
1002                 .iov_base = fail_req->iu->buf,
1003                 .iov_len  = fail_req->usr_len
1004         };
1005
1006         req = &alive_path->reqs[fail_req->permit->mem_id];
1007         rtrs_clt_init_req(req, alive_path, fail_req->conf, fail_req->permit,
1008                            fail_req->priv, &vec, fail_req->usr_len,
1009                            fail_req->sglist, fail_req->sg_cnt,
1010                            fail_req->data_len, fail_req->dir);
1011         return req;
1012 }
1013
1014 static int rtrs_post_rdma_write_sg(struct rtrs_clt_con *con,
1015                                    struct rtrs_clt_io_req *req,
1016                                    struct rtrs_rbuf *rbuf, bool fr_en,
1017                                    u32 size, u32 imm, struct ib_send_wr *wr,
1018                                    struct ib_send_wr *tail)
1019 {
1020         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1021         struct ib_sge *sge = req->sge;
1022         enum ib_send_flags flags;
1023         struct scatterlist *sg;
1024         size_t num_sge;
1025         int i;
1026         struct ib_send_wr *ptail = NULL;
1027
1028         if (fr_en) {
1029                 i = 0;
1030                 sge[i].addr   = req->mr->iova;
1031                 sge[i].length = req->mr->length;
1032                 sge[i].lkey   = req->mr->lkey;
1033                 i++;
1034                 num_sge = 2;
1035                 ptail = tail;
1036         } else {
1037                 for_each_sg(req->sglist, sg, req->sg_cnt, i) {
1038                         sge[i].addr   = sg_dma_address(sg);
1039                         sge[i].length = sg_dma_len(sg);
1040                         sge[i].lkey   = clt_path->s.dev->ib_pd->local_dma_lkey;
1041                 }
1042                 num_sge = 1 + req->sg_cnt;
1043         }
1044         sge[i].addr   = req->iu->dma_addr;
1045         sge[i].length = size;
1046         sge[i].lkey   = clt_path->s.dev->ib_pd->local_dma_lkey;
1047
1048         /*
1049          * From time to time we have to post signalled sends,
1050          * or send queue will fill up and only QP reset can help.
1051          */
1052         flags = atomic_inc_return(&con->c.wr_cnt) % clt_path->s.signal_interval ?
1053                         0 : IB_SEND_SIGNALED;
1054
1055         ib_dma_sync_single_for_device(clt_path->s.dev->ib_dev,
1056                                       req->iu->dma_addr,
1057                                       size, DMA_TO_DEVICE);
1058
1059         return rtrs_iu_post_rdma_write_imm(&con->c, req->iu, sge, num_sge,
1060                                             rbuf->rkey, rbuf->addr, imm,
1061                                             flags, wr, ptail);
1062 }
1063
1064 static int rtrs_map_sg_fr(struct rtrs_clt_io_req *req, size_t count)
1065 {
1066         int nr;
1067
1068         /* Align the MR to a 4K page size to match the block virt boundary */
1069         nr = ib_map_mr_sg(req->mr, req->sglist, count, NULL, SZ_4K);
1070         if (nr < 0)
1071                 return nr;
1072         if (nr < req->sg_cnt)
1073                 return -EINVAL;
1074         ib_update_fast_reg_key(req->mr, ib_inc_rkey(req->mr->rkey));
1075
1076         return nr;
1077 }
1078
1079 static int rtrs_clt_write_req(struct rtrs_clt_io_req *req)
1080 {
1081         struct rtrs_clt_con *con = req->con;
1082         struct rtrs_path *s = con->c.path;
1083         struct rtrs_clt_path *clt_path = to_clt_path(s);
1084         struct rtrs_msg_rdma_write *msg;
1085
1086         struct rtrs_rbuf *rbuf;
1087         int ret, count = 0;
1088         u32 imm, buf_id;
1089         struct ib_reg_wr rwr;
1090         struct ib_send_wr inv_wr;
1091         struct ib_send_wr *wr = NULL;
1092         bool fr_en = false;
1093
1094         const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len;
1095
1096         if (tsize > clt_path->chunk_size) {
1097                 rtrs_wrn(s, "Write request failed, size too big %zu > %d\n",
1098                           tsize, clt_path->chunk_size);
1099                 return -EMSGSIZE;
1100         }
1101         if (req->sg_cnt) {
1102                 count = ib_dma_map_sg(clt_path->s.dev->ib_dev, req->sglist,
1103                                       req->sg_cnt, req->dir);
1104                 if (!count) {
1105                         rtrs_wrn(s, "Write request failed, map failed\n");
1106                         return -EINVAL;
1107                 }
1108         }
1109         /* put rtrs msg after sg and user message */
1110         msg = req->iu->buf + req->usr_len;
1111         msg->type = cpu_to_le16(RTRS_MSG_WRITE);
1112         msg->usr_len = cpu_to_le16(req->usr_len);
1113
1114         /* rtrs message on server side will be after user data and message */
1115         imm = req->permit->mem_off + req->data_len + req->usr_len;
1116         imm = rtrs_to_io_req_imm(imm);
1117         buf_id = req->permit->mem_id;
1118         req->sg_size = tsize;
1119         rbuf = &clt_path->rbufs[buf_id];
1120
1121         if (count) {
1122                 ret = rtrs_map_sg_fr(req, count);
1123                 if (ret < 0) {
1124                         rtrs_err_rl(s,
1125                                     "Write request failed, failed to map fast reg. data, err: %d\n",
1126                                     ret);
1127                         ib_dma_unmap_sg(clt_path->s.dev->ib_dev, req->sglist,
1128                                         req->sg_cnt, req->dir);
1129                         return ret;
1130                 }
1131                 inv_wr = (struct ib_send_wr) {
1132                         .opcode             = IB_WR_LOCAL_INV,
1133                         .wr_cqe             = &req->inv_cqe,
1134                         .send_flags         = IB_SEND_SIGNALED,
1135                         .ex.invalidate_rkey = req->mr->rkey,
1136                 };
1137                 req->inv_cqe.done = rtrs_clt_inv_rkey_done;
1138                 rwr = (struct ib_reg_wr) {
1139                         .wr.opcode = IB_WR_REG_MR,
1140                         .wr.wr_cqe = &fast_reg_cqe,
1141                         .mr = req->mr,
1142                         .key = req->mr->rkey,
1143                         .access = (IB_ACCESS_LOCAL_WRITE),
1144                 };
1145                 wr = &rwr.wr;
1146                 fr_en = true;
1147                 refcount_inc(&req->ref);
1148         }
1149         /*
1150          * Update stats now, after request is successfully sent it is not
1151          * safe anymore to touch it.
1152          */
1153         rtrs_clt_update_all_stats(req, WRITE);
1154
1155         ret = rtrs_post_rdma_write_sg(req->con, req, rbuf, fr_en,
1156                                       req->usr_len + sizeof(*msg),
1157                                       imm, wr, &inv_wr);
1158         if (ret) {
1159                 rtrs_err_rl(s,
1160                             "Write request failed: error=%d path=%s [%s:%u]\n",
1161                             ret, kobject_name(&clt_path->kobj), clt_path->hca_name,
1162                             clt_path->hca_port);
1163                 if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
1164                         atomic_dec(&clt_path->stats->inflight);
1165                 if (req->sg_cnt)
1166                         ib_dma_unmap_sg(clt_path->s.dev->ib_dev, req->sglist,
1167                                         req->sg_cnt, req->dir);
1168         }
1169
1170         return ret;
1171 }
1172
1173 static int rtrs_clt_read_req(struct rtrs_clt_io_req *req)
1174 {
1175         struct rtrs_clt_con *con = req->con;
1176         struct rtrs_path *s = con->c.path;
1177         struct rtrs_clt_path *clt_path = to_clt_path(s);
1178         struct rtrs_msg_rdma_read *msg;
1179         struct rtrs_ib_dev *dev = clt_path->s.dev;
1180
1181         struct ib_reg_wr rwr;
1182         struct ib_send_wr *wr = NULL;
1183
1184         int ret, count = 0;
1185         u32 imm, buf_id;
1186
1187         const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len;
1188
1189         if (tsize > clt_path->chunk_size) {
1190                 rtrs_wrn(s,
1191                           "Read request failed, message size is %zu, bigger than CHUNK_SIZE %d\n",
1192                           tsize, clt_path->chunk_size);
1193                 return -EMSGSIZE;
1194         }
1195
1196         if (req->sg_cnt) {
1197                 count = ib_dma_map_sg(dev->ib_dev, req->sglist, req->sg_cnt,
1198                                       req->dir);
1199                 if (!count) {
1200                         rtrs_wrn(s,
1201                                   "Read request failed, dma map failed\n");
1202                         return -EINVAL;
1203                 }
1204         }
1205         /* put our message into req->buf after user message*/
1206         msg = req->iu->buf + req->usr_len;
1207         msg->type = cpu_to_le16(RTRS_MSG_READ);
1208         msg->usr_len = cpu_to_le16(req->usr_len);
1209
1210         if (count) {
1211                 ret = rtrs_map_sg_fr(req, count);
1212                 if (ret < 0) {
1213                         rtrs_err_rl(s,
1214                                      "Read request failed, failed to map  fast reg. data, err: %d\n",
1215                                      ret);
1216                         ib_dma_unmap_sg(dev->ib_dev, req->sglist, req->sg_cnt,
1217                                         req->dir);
1218                         return ret;
1219                 }
1220                 rwr = (struct ib_reg_wr) {
1221                         .wr.opcode = IB_WR_REG_MR,
1222                         .wr.wr_cqe = &fast_reg_cqe,
1223                         .mr = req->mr,
1224                         .key = req->mr->rkey,
1225                         .access = (IB_ACCESS_LOCAL_WRITE |
1226                                    IB_ACCESS_REMOTE_WRITE),
1227                 };
1228                 wr = &rwr.wr;
1229
1230                 msg->sg_cnt = cpu_to_le16(1);
1231                 msg->flags = cpu_to_le16(RTRS_MSG_NEED_INVAL_F);
1232
1233                 msg->desc[0].addr = cpu_to_le64(req->mr->iova);
1234                 msg->desc[0].key = cpu_to_le32(req->mr->rkey);
1235                 msg->desc[0].len = cpu_to_le32(req->mr->length);
1236
1237                 /* Further invalidation is required */
1238                 req->need_inv = !!RTRS_MSG_NEED_INVAL_F;
1239
1240         } else {
1241                 msg->sg_cnt = 0;
1242                 msg->flags = 0;
1243         }
1244         /*
1245          * rtrs message will be after the space reserved for disk data and
1246          * user message
1247          */
1248         imm = req->permit->mem_off + req->data_len + req->usr_len;
1249         imm = rtrs_to_io_req_imm(imm);
1250         buf_id = req->permit->mem_id;
1251
1252         req->sg_size  = sizeof(*msg);
1253         req->sg_size += le16_to_cpu(msg->sg_cnt) * sizeof(struct rtrs_sg_desc);
1254         req->sg_size += req->usr_len;
1255
1256         /*
1257          * Update stats now, after request is successfully sent it is not
1258          * safe anymore to touch it.
1259          */
1260         rtrs_clt_update_all_stats(req, READ);
1261
1262         ret = rtrs_post_send_rdma(req->con, req, &clt_path->rbufs[buf_id],
1263                                    req->data_len, imm, wr);
1264         if (ret) {
1265                 rtrs_err_rl(s,
1266                             "Read request failed: error=%d path=%s [%s:%u]\n",
1267                             ret, kobject_name(&clt_path->kobj), clt_path->hca_name,
1268                             clt_path->hca_port);
1269                 if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
1270                         atomic_dec(&clt_path->stats->inflight);
1271                 req->need_inv = false;
1272                 if (req->sg_cnt)
1273                         ib_dma_unmap_sg(dev->ib_dev, req->sglist,
1274                                         req->sg_cnt, req->dir);
1275         }
1276
1277         return ret;
1278 }
1279
1280 /**
1281  * rtrs_clt_failover_req() - Try to find an active path for a failed request
1282  * @clt: clt context
1283  * @fail_req: a failed io request.
1284  */
1285 static int rtrs_clt_failover_req(struct rtrs_clt_sess *clt,
1286                                  struct rtrs_clt_io_req *fail_req)
1287 {
1288         struct rtrs_clt_path *alive_path;
1289         struct rtrs_clt_io_req *req;
1290         int err = -ECONNABORTED;
1291         struct path_it it;
1292
1293         rcu_read_lock();
1294         for (path_it_init(&it, clt);
1295              (alive_path = it.next_path(&it)) && it.i < it.clt->paths_num;
1296              it.i++) {
1297                 if (READ_ONCE(alive_path->state) != RTRS_CLT_CONNECTED)
1298                         continue;
1299                 req = rtrs_clt_get_copy_req(alive_path, fail_req);
1300                 if (req->dir == DMA_TO_DEVICE)
1301                         err = rtrs_clt_write_req(req);
1302                 else
1303                         err = rtrs_clt_read_req(req);
1304                 if (err) {
1305                         req->in_use = false;
1306                         continue;
1307                 }
1308                 /* Success path */
1309                 rtrs_clt_inc_failover_cnt(alive_path->stats);
1310                 break;
1311         }
1312         path_it_deinit(&it);
1313         rcu_read_unlock();
1314
1315         return err;
1316 }
1317
1318 static void fail_all_outstanding_reqs(struct rtrs_clt_path *clt_path)
1319 {
1320         struct rtrs_clt_sess *clt = clt_path->clt;
1321         struct rtrs_clt_io_req *req;
1322         int i, err;
1323
1324         if (!clt_path->reqs)
1325                 return;
1326         for (i = 0; i < clt_path->queue_depth; ++i) {
1327                 req = &clt_path->reqs[i];
1328                 if (!req->in_use)
1329                         continue;
1330
1331                 /*
1332                  * Safely (without notification) complete failed request.
1333                  * After completion this request is still useble and can
1334                  * be failovered to another path.
1335                  */
1336                 complete_rdma_req(req, -ECONNABORTED, false, true);
1337
1338                 err = rtrs_clt_failover_req(clt, req);
1339                 if (err)
1340                         /* Failover failed, notify anyway */
1341                         req->conf(req->priv, err);
1342         }
1343 }
1344
1345 static void free_path_reqs(struct rtrs_clt_path *clt_path)
1346 {
1347         struct rtrs_clt_io_req *req;
1348         int i;
1349
1350         if (!clt_path->reqs)
1351                 return;
1352         for (i = 0; i < clt_path->queue_depth; ++i) {
1353                 req = &clt_path->reqs[i];
1354                 if (req->mr)
1355                         ib_dereg_mr(req->mr);
1356                 kfree(req->sge);
1357                 rtrs_iu_free(req->iu, clt_path->s.dev->ib_dev, 1);
1358         }
1359         kfree(clt_path->reqs);
1360         clt_path->reqs = NULL;
1361 }
1362
1363 static int alloc_path_reqs(struct rtrs_clt_path *clt_path)
1364 {
1365         struct rtrs_clt_io_req *req;
1366         int i, err = -ENOMEM;
1367
1368         clt_path->reqs = kcalloc(clt_path->queue_depth,
1369                                  sizeof(*clt_path->reqs),
1370                                  GFP_KERNEL);
1371         if (!clt_path->reqs)
1372                 return -ENOMEM;
1373
1374         for (i = 0; i < clt_path->queue_depth; ++i) {
1375                 req = &clt_path->reqs[i];
1376                 req->iu = rtrs_iu_alloc(1, clt_path->max_hdr_size, GFP_KERNEL,
1377                                          clt_path->s.dev->ib_dev,
1378                                          DMA_TO_DEVICE,
1379                                          rtrs_clt_rdma_done);
1380                 if (!req->iu)
1381                         goto out;
1382
1383                 req->sge = kcalloc(2, sizeof(*req->sge), GFP_KERNEL);
1384                 if (!req->sge)
1385                         goto out;
1386
1387                 req->mr = ib_alloc_mr(clt_path->s.dev->ib_pd,
1388                                       IB_MR_TYPE_MEM_REG,
1389                                       clt_path->max_pages_per_mr);
1390                 if (IS_ERR(req->mr)) {
1391                         err = PTR_ERR(req->mr);
1392                         req->mr = NULL;
1393                         pr_err("Failed to alloc clt_path->max_pages_per_mr %d\n",
1394                                clt_path->max_pages_per_mr);
1395                         goto out;
1396                 }
1397
1398                 init_completion(&req->inv_comp);
1399         }
1400
1401         return 0;
1402
1403 out:
1404         free_path_reqs(clt_path);
1405
1406         return err;
1407 }
1408
1409 static int alloc_permits(struct rtrs_clt_sess *clt)
1410 {
1411         unsigned int chunk_bits;
1412         int err, i;
1413
1414         clt->permits_map = kcalloc(BITS_TO_LONGS(clt->queue_depth),
1415                                    sizeof(long), GFP_KERNEL);
1416         if (!clt->permits_map) {
1417                 err = -ENOMEM;
1418                 goto out_err;
1419         }
1420         clt->permits = kcalloc(clt->queue_depth, permit_size(clt), GFP_KERNEL);
1421         if (!clt->permits) {
1422                 err = -ENOMEM;
1423                 goto err_map;
1424         }
1425         chunk_bits = ilog2(clt->queue_depth - 1) + 1;
1426         for (i = 0; i < clt->queue_depth; i++) {
1427                 struct rtrs_permit *permit;
1428
1429                 permit = get_permit(clt, i);
1430                 permit->mem_id = i;
1431                 permit->mem_off = i << (MAX_IMM_PAYL_BITS - chunk_bits);
1432         }
1433
1434         return 0;
1435
1436 err_map:
1437         kfree(clt->permits_map);
1438         clt->permits_map = NULL;
1439 out_err:
1440         return err;
1441 }
1442
1443 static void free_permits(struct rtrs_clt_sess *clt)
1444 {
1445         if (clt->permits_map) {
1446                 size_t sz = clt->queue_depth;
1447
1448                 wait_event(clt->permits_wait,
1449                            find_first_bit(clt->permits_map, sz) >= sz);
1450         }
1451         kfree(clt->permits_map);
1452         clt->permits_map = NULL;
1453         kfree(clt->permits);
1454         clt->permits = NULL;
1455 }
1456
1457 static void query_fast_reg_mode(struct rtrs_clt_path *clt_path)
1458 {
1459         struct ib_device *ib_dev;
1460         u64 max_pages_per_mr;
1461         int mr_page_shift;
1462
1463         ib_dev = clt_path->s.dev->ib_dev;
1464
1465         /*
1466          * Use the smallest page size supported by the HCA, down to a
1467          * minimum of 4096 bytes. We're unlikely to build large sglists
1468          * out of smaller entries.
1469          */
1470         mr_page_shift      = max(12, ffs(ib_dev->attrs.page_size_cap) - 1);
1471         max_pages_per_mr   = ib_dev->attrs.max_mr_size;
1472         do_div(max_pages_per_mr, (1ull << mr_page_shift));
1473         clt_path->max_pages_per_mr =
1474                 min3(clt_path->max_pages_per_mr, (u32)max_pages_per_mr,
1475                      ib_dev->attrs.max_fast_reg_page_list_len);
1476         clt_path->clt->max_segments =
1477                 min(clt_path->max_pages_per_mr, clt_path->clt->max_segments);
1478 }
1479
1480 static bool rtrs_clt_change_state_get_old(struct rtrs_clt_path *clt_path,
1481                                            enum rtrs_clt_state new_state,
1482                                            enum rtrs_clt_state *old_state)
1483 {
1484         bool changed;
1485
1486         spin_lock_irq(&clt_path->state_wq.lock);
1487         if (old_state)
1488                 *old_state = clt_path->state;
1489         changed = rtrs_clt_change_state(clt_path, new_state);
1490         spin_unlock_irq(&clt_path->state_wq.lock);
1491
1492         return changed;
1493 }
1494
1495 static void rtrs_clt_hb_err_handler(struct rtrs_con *c)
1496 {
1497         struct rtrs_clt_con *con = container_of(c, typeof(*con), c);
1498
1499         rtrs_rdma_error_recovery(con);
1500 }
1501
1502 static void rtrs_clt_init_hb(struct rtrs_clt_path *clt_path)
1503 {
1504         rtrs_init_hb(&clt_path->s, &io_comp_cqe,
1505                       RTRS_HB_INTERVAL_MS,
1506                       RTRS_HB_MISSED_MAX,
1507                       rtrs_clt_hb_err_handler,
1508                       rtrs_wq);
1509 }
1510
1511 static void rtrs_clt_reconnect_work(struct work_struct *work);
1512 static void rtrs_clt_close_work(struct work_struct *work);
1513
1514 static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt,
1515                                         const struct rtrs_addr *path,
1516                                         size_t con_num, u32 nr_poll_queues)
1517 {
1518         struct rtrs_clt_path *clt_path;
1519         int err = -ENOMEM;
1520         int cpu;
1521         size_t total_con;
1522
1523         clt_path = kzalloc(sizeof(*clt_path), GFP_KERNEL);
1524         if (!clt_path)
1525                 goto err;
1526
1527         /*
1528          * irqmode and poll
1529          * +1: Extra connection for user messages
1530          */
1531         total_con = con_num + nr_poll_queues + 1;
1532         clt_path->s.con = kcalloc(total_con, sizeof(*clt_path->s.con),
1533                                   GFP_KERNEL);
1534         if (!clt_path->s.con)
1535                 goto err_free_path;
1536
1537         clt_path->s.con_num = total_con;
1538         clt_path->s.irq_con_num = con_num + 1;
1539
1540         clt_path->stats = kzalloc(sizeof(*clt_path->stats), GFP_KERNEL);
1541         if (!clt_path->stats)
1542                 goto err_free_con;
1543
1544         mutex_init(&clt_path->init_mutex);
1545         uuid_gen(&clt_path->s.uuid);
1546         memcpy(&clt_path->s.dst_addr, path->dst,
1547                rdma_addr_size((struct sockaddr *)path->dst));
1548
1549         /*
1550          * rdma_resolve_addr() passes src_addr to cma_bind_addr, which
1551          * checks the sa_family to be non-zero. If user passed src_addr=NULL
1552          * the sess->src_addr will contain only zeros, which is then fine.
1553          */
1554         if (path->src)
1555                 memcpy(&clt_path->s.src_addr, path->src,
1556                        rdma_addr_size((struct sockaddr *)path->src));
1557         strscpy(clt_path->s.sessname, clt->sessname,
1558                 sizeof(clt_path->s.sessname));
1559         clt_path->clt = clt;
1560         clt_path->max_pages_per_mr = RTRS_MAX_SEGMENTS;
1561         init_waitqueue_head(&clt_path->state_wq);
1562         clt_path->state = RTRS_CLT_CONNECTING;
1563         atomic_set(&clt_path->connected_cnt, 0);
1564         INIT_WORK(&clt_path->close_work, rtrs_clt_close_work);
1565         INIT_DELAYED_WORK(&clt_path->reconnect_dwork, rtrs_clt_reconnect_work);
1566         rtrs_clt_init_hb(clt_path);
1567
1568         clt_path->mp_skip_entry = alloc_percpu(typeof(*clt_path->mp_skip_entry));
1569         if (!clt_path->mp_skip_entry)
1570                 goto err_free_stats;
1571
1572         for_each_possible_cpu(cpu)
1573                 INIT_LIST_HEAD(per_cpu_ptr(clt_path->mp_skip_entry, cpu));
1574
1575         err = rtrs_clt_init_stats(clt_path->stats);
1576         if (err)
1577                 goto err_free_percpu;
1578
1579         return clt_path;
1580
1581 err_free_percpu:
1582         free_percpu(clt_path->mp_skip_entry);
1583 err_free_stats:
1584         kfree(clt_path->stats);
1585 err_free_con:
1586         kfree(clt_path->s.con);
1587 err_free_path:
1588         kfree(clt_path);
1589 err:
1590         return ERR_PTR(err);
1591 }
1592
1593 void free_path(struct rtrs_clt_path *clt_path)
1594 {
1595         free_percpu(clt_path->mp_skip_entry);
1596         mutex_destroy(&clt_path->init_mutex);
1597         kfree(clt_path->s.con);
1598         kfree(clt_path->rbufs);
1599         kfree(clt_path);
1600 }
1601
1602 static int create_con(struct rtrs_clt_path *clt_path, unsigned int cid)
1603 {
1604         struct rtrs_clt_con *con;
1605
1606         con = kzalloc(sizeof(*con), GFP_KERNEL);
1607         if (!con)
1608                 return -ENOMEM;
1609
1610         /* Map first two connections to the first CPU */
1611         con->cpu  = (cid ? cid - 1 : 0) % nr_cpu_ids;
1612         con->c.cid = cid;
1613         con->c.path = &clt_path->s;
1614         /* Align with srv, init as 1 */
1615         atomic_set(&con->c.wr_cnt, 1);
1616         mutex_init(&con->con_mutex);
1617
1618         clt_path->s.con[cid] = &con->c;
1619
1620         return 0;
1621 }
1622
1623 static void destroy_con(struct rtrs_clt_con *con)
1624 {
1625         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1626
1627         clt_path->s.con[con->c.cid] = NULL;
1628         mutex_destroy(&con->con_mutex);
1629         kfree(con);
1630 }
1631
1632 static int create_con_cq_qp(struct rtrs_clt_con *con)
1633 {
1634         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1635         u32 max_send_wr, max_recv_wr, cq_num, max_send_sge, wr_limit;
1636         int err, cq_vector;
1637         struct rtrs_msg_rkey_rsp *rsp;
1638
1639         lockdep_assert_held(&con->con_mutex);
1640         if (con->c.cid == 0) {
1641                 max_send_sge = 1;
1642                 /* We must be the first here */
1643                 if (WARN_ON(clt_path->s.dev))
1644                         return -EINVAL;
1645
1646                 /*
1647                  * The whole session uses device from user connection.
1648                  * Be careful not to close user connection before ib dev
1649                  * is gracefully put.
1650                  */
1651                 clt_path->s.dev = rtrs_ib_dev_find_or_add(con->c.cm_id->device,
1652                                                        &dev_pd);
1653                 if (!clt_path->s.dev) {
1654                         rtrs_wrn(clt_path->clt,
1655                                   "rtrs_ib_dev_find_get_or_add(): no memory\n");
1656                         return -ENOMEM;
1657                 }
1658                 clt_path->s.dev_ref = 1;
1659                 query_fast_reg_mode(clt_path);
1660                 wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr;
1661                 /*
1662                  * Two (request + registration) completion for send
1663                  * Two for recv if always_invalidate is set on server
1664                  * or one for recv.
1665                  * + 2 for drain and heartbeat
1666                  * in case qp gets into error state.
1667                  */
1668                 max_send_wr =
1669                         min_t(int, wr_limit, SERVICE_CON_QUEUE_DEPTH * 2 + 2);
1670                 max_recv_wr = max_send_wr;
1671         } else {
1672                 /*
1673                  * Here we assume that session members are correctly set.
1674                  * This is always true if user connection (cid == 0) is
1675                  * established first.
1676                  */
1677                 if (WARN_ON(!clt_path->s.dev))
1678                         return -EINVAL;
1679                 if (WARN_ON(!clt_path->queue_depth))
1680                         return -EINVAL;
1681
1682                 wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr;
1683                 /* Shared between connections */
1684                 clt_path->s.dev_ref++;
1685                 max_send_wr = min_t(int, wr_limit,
1686                               /* QD * (REQ + RSP + FR REGS or INVS) + drain */
1687                               clt_path->queue_depth * 3 + 1);
1688                 max_recv_wr = min_t(int, wr_limit,
1689                               clt_path->queue_depth * 3 + 1);
1690                 max_send_sge = 2;
1691         }
1692         atomic_set(&con->c.sq_wr_avail, max_send_wr);
1693         cq_num = max_send_wr + max_recv_wr;
1694         /* alloc iu to recv new rkey reply when server reports flags set */
1695         if (clt_path->flags & RTRS_MSG_NEW_RKEY_F || con->c.cid == 0) {
1696                 con->rsp_ius = rtrs_iu_alloc(cq_num, sizeof(*rsp),
1697                                               GFP_KERNEL,
1698                                               clt_path->s.dev->ib_dev,
1699                                               DMA_FROM_DEVICE,
1700                                               rtrs_clt_rdma_done);
1701                 if (!con->rsp_ius)
1702                         return -ENOMEM;
1703                 con->queue_num = cq_num;
1704         }
1705         cq_num = max_send_wr + max_recv_wr;
1706         cq_vector = con->cpu % clt_path->s.dev->ib_dev->num_comp_vectors;
1707         if (con->c.cid >= clt_path->s.irq_con_num)
1708                 err = rtrs_cq_qp_create(&clt_path->s, &con->c, max_send_sge,
1709                                         cq_vector, cq_num, max_send_wr,
1710                                         max_recv_wr, IB_POLL_DIRECT);
1711         else
1712                 err = rtrs_cq_qp_create(&clt_path->s, &con->c, max_send_sge,
1713                                         cq_vector, cq_num, max_send_wr,
1714                                         max_recv_wr, IB_POLL_SOFTIRQ);
1715         /*
1716          * In case of error we do not bother to clean previous allocations,
1717          * since destroy_con_cq_qp() must be called.
1718          */
1719         return err;
1720 }
1721
1722 static void destroy_con_cq_qp(struct rtrs_clt_con *con)
1723 {
1724         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1725
1726         /*
1727          * Be careful here: destroy_con_cq_qp() can be called even
1728          * create_con_cq_qp() failed, see comments there.
1729          */
1730         lockdep_assert_held(&con->con_mutex);
1731         rtrs_cq_qp_destroy(&con->c);
1732         if (con->rsp_ius) {
1733                 rtrs_iu_free(con->rsp_ius, clt_path->s.dev->ib_dev,
1734                              con->queue_num);
1735                 con->rsp_ius = NULL;
1736                 con->queue_num = 0;
1737         }
1738         if (clt_path->s.dev_ref && !--clt_path->s.dev_ref) {
1739                 rtrs_ib_dev_put(clt_path->s.dev);
1740                 clt_path->s.dev = NULL;
1741         }
1742 }
1743
1744 static void stop_cm(struct rtrs_clt_con *con)
1745 {
1746         rdma_disconnect(con->c.cm_id);
1747         if (con->c.qp)
1748                 ib_drain_qp(con->c.qp);
1749 }
1750
1751 static void destroy_cm(struct rtrs_clt_con *con)
1752 {
1753         rdma_destroy_id(con->c.cm_id);
1754         con->c.cm_id = NULL;
1755 }
1756
1757 static int rtrs_rdma_addr_resolved(struct rtrs_clt_con *con)
1758 {
1759         struct rtrs_path *s = con->c.path;
1760         int err;
1761
1762         mutex_lock(&con->con_mutex);
1763         err = create_con_cq_qp(con);
1764         mutex_unlock(&con->con_mutex);
1765         if (err) {
1766                 rtrs_err(s, "create_con_cq_qp(), err: %d\n", err);
1767                 return err;
1768         }
1769         err = rdma_resolve_route(con->c.cm_id, RTRS_CONNECT_TIMEOUT_MS);
1770         if (err)
1771                 rtrs_err(s, "Resolving route failed, err: %d\n", err);
1772
1773         return err;
1774 }
1775
1776 static int rtrs_rdma_route_resolved(struct rtrs_clt_con *con)
1777 {
1778         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1779         struct rtrs_clt_sess *clt = clt_path->clt;
1780         struct rtrs_msg_conn_req msg;
1781         struct rdma_conn_param param;
1782
1783         int err;
1784
1785         param = (struct rdma_conn_param) {
1786                 .retry_count = 7,
1787                 .rnr_retry_count = 7,
1788                 .private_data = &msg,
1789                 .private_data_len = sizeof(msg),
1790         };
1791
1792         msg = (struct rtrs_msg_conn_req) {
1793                 .magic = cpu_to_le16(RTRS_MAGIC),
1794                 .version = cpu_to_le16(RTRS_PROTO_VER),
1795                 .cid = cpu_to_le16(con->c.cid),
1796                 .cid_num = cpu_to_le16(clt_path->s.con_num),
1797                 .recon_cnt = cpu_to_le16(clt_path->s.recon_cnt),
1798         };
1799         msg.first_conn = clt_path->for_new_clt ? FIRST_CONN : 0;
1800         uuid_copy(&msg.sess_uuid, &clt_path->s.uuid);
1801         uuid_copy(&msg.paths_uuid, &clt->paths_uuid);
1802
1803         err = rdma_connect_locked(con->c.cm_id, &param);
1804         if (err)
1805                 rtrs_err(clt, "rdma_connect_locked(): %d\n", err);
1806
1807         return err;
1808 }
1809
1810 static int rtrs_rdma_conn_established(struct rtrs_clt_con *con,
1811                                        struct rdma_cm_event *ev)
1812 {
1813         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1814         struct rtrs_clt_sess *clt = clt_path->clt;
1815         const struct rtrs_msg_conn_rsp *msg;
1816         u16 version, queue_depth;
1817         int errno;
1818         u8 len;
1819
1820         msg = ev->param.conn.private_data;
1821         len = ev->param.conn.private_data_len;
1822         if (len < sizeof(*msg)) {
1823                 rtrs_err(clt, "Invalid RTRS connection response\n");
1824                 return -ECONNRESET;
1825         }
1826         if (le16_to_cpu(msg->magic) != RTRS_MAGIC) {
1827                 rtrs_err(clt, "Invalid RTRS magic\n");
1828                 return -ECONNRESET;
1829         }
1830         version = le16_to_cpu(msg->version);
1831         if (version >> 8 != RTRS_PROTO_VER_MAJOR) {
1832                 rtrs_err(clt, "Unsupported major RTRS version: %d, expected %d\n",
1833                           version >> 8, RTRS_PROTO_VER_MAJOR);
1834                 return -ECONNRESET;
1835         }
1836         errno = le16_to_cpu(msg->errno);
1837         if (errno) {
1838                 rtrs_err(clt, "Invalid RTRS message: errno %d\n",
1839                           errno);
1840                 return -ECONNRESET;
1841         }
1842         if (con->c.cid == 0) {
1843                 queue_depth = le16_to_cpu(msg->queue_depth);
1844
1845                 if (clt_path->queue_depth > 0 && queue_depth != clt_path->queue_depth) {
1846                         rtrs_err(clt, "Error: queue depth changed\n");
1847
1848                         /*
1849                          * Stop any more reconnection attempts
1850                          */
1851                         clt_path->reconnect_attempts = -1;
1852                         rtrs_err(clt,
1853                                 "Disabling auto-reconnect. Trigger a manual reconnect after issue is resolved\n");
1854                         return -ECONNRESET;
1855                 }
1856
1857                 if (!clt_path->rbufs) {
1858                         clt_path->rbufs = kcalloc(queue_depth,
1859                                                   sizeof(*clt_path->rbufs),
1860                                                   GFP_KERNEL);
1861                         if (!clt_path->rbufs)
1862                                 return -ENOMEM;
1863                 }
1864                 clt_path->queue_depth = queue_depth;
1865                 clt_path->s.signal_interval = min_not_zero(queue_depth,
1866                                                 (unsigned short) SERVICE_CON_QUEUE_DEPTH);
1867                 clt_path->max_hdr_size = le32_to_cpu(msg->max_hdr_size);
1868                 clt_path->max_io_size = le32_to_cpu(msg->max_io_size);
1869                 clt_path->flags = le32_to_cpu(msg->flags);
1870                 clt_path->chunk_size = clt_path->max_io_size + clt_path->max_hdr_size;
1871
1872                 /*
1873                  * Global IO size is always a minimum.
1874                  * If while a reconnection server sends us a value a bit
1875                  * higher - client does not care and uses cached minimum.
1876                  *
1877                  * Since we can have several sessions (paths) restablishing
1878                  * connections in parallel, use lock.
1879                  */
1880                 mutex_lock(&clt->paths_mutex);
1881                 clt->queue_depth = clt_path->queue_depth;
1882                 clt->max_io_size = min_not_zero(clt_path->max_io_size,
1883                                                 clt->max_io_size);
1884                 mutex_unlock(&clt->paths_mutex);
1885
1886                 /*
1887                  * Cache the hca_port and hca_name for sysfs
1888                  */
1889                 clt_path->hca_port = con->c.cm_id->port_num;
1890                 scnprintf(clt_path->hca_name, sizeof(clt_path->hca_name),
1891                           clt_path->s.dev->ib_dev->name);
1892                 clt_path->s.src_addr = con->c.cm_id->route.addr.src_addr;
1893                 /* set for_new_clt, to allow future reconnect on any path */
1894                 clt_path->for_new_clt = 1;
1895         }
1896
1897         return 0;
1898 }
1899
1900 static inline void flag_success_on_conn(struct rtrs_clt_con *con)
1901 {
1902         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
1903
1904         atomic_inc(&clt_path->connected_cnt);
1905         con->cm_err = 1;
1906 }
1907
1908 static int rtrs_rdma_conn_rejected(struct rtrs_clt_con *con,
1909                                     struct rdma_cm_event *ev)
1910 {
1911         struct rtrs_path *s = con->c.path;
1912         const struct rtrs_msg_conn_rsp *msg;
1913         const char *rej_msg;
1914         int status, errno;
1915         u8 data_len;
1916
1917         status = ev->status;
1918         rej_msg = rdma_reject_msg(con->c.cm_id, status);
1919         msg = rdma_consumer_reject_data(con->c.cm_id, ev, &data_len);
1920
1921         if (msg && data_len >= sizeof(*msg)) {
1922                 errno = (int16_t)le16_to_cpu(msg->errno);
1923                 if (errno == -EBUSY)
1924                         rtrs_err(s,
1925                                   "Previous session is still exists on the server, please reconnect later\n");
1926                 else
1927                         rtrs_err(s,
1928                                   "Connect rejected: status %d (%s), rtrs errno %d\n",
1929                                   status, rej_msg, errno);
1930         } else {
1931                 rtrs_err(s,
1932                           "Connect rejected but with malformed message: status %d (%s)\n",
1933                           status, rej_msg);
1934         }
1935
1936         return -ECONNRESET;
1937 }
1938
1939 void rtrs_clt_close_conns(struct rtrs_clt_path *clt_path, bool wait)
1940 {
1941         if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CLOSING, NULL))
1942                 queue_work(rtrs_wq, &clt_path->close_work);
1943         if (wait)
1944                 flush_work(&clt_path->close_work);
1945 }
1946
1947 static inline void flag_error_on_conn(struct rtrs_clt_con *con, int cm_err)
1948 {
1949         if (con->cm_err == 1) {
1950                 struct rtrs_clt_path *clt_path;
1951
1952                 clt_path = to_clt_path(con->c.path);
1953                 if (atomic_dec_and_test(&clt_path->connected_cnt))
1954
1955                         wake_up(&clt_path->state_wq);
1956         }
1957         con->cm_err = cm_err;
1958 }
1959
1960 static int rtrs_clt_rdma_cm_handler(struct rdma_cm_id *cm_id,
1961                                      struct rdma_cm_event *ev)
1962 {
1963         struct rtrs_clt_con *con = cm_id->context;
1964         struct rtrs_path *s = con->c.path;
1965         struct rtrs_clt_path *clt_path = to_clt_path(s);
1966         int cm_err = 0;
1967
1968         switch (ev->event) {
1969         case RDMA_CM_EVENT_ADDR_RESOLVED:
1970                 cm_err = rtrs_rdma_addr_resolved(con);
1971                 break;
1972         case RDMA_CM_EVENT_ROUTE_RESOLVED:
1973                 cm_err = rtrs_rdma_route_resolved(con);
1974                 break;
1975         case RDMA_CM_EVENT_ESTABLISHED:
1976                 cm_err = rtrs_rdma_conn_established(con, ev);
1977                 if (!cm_err) {
1978                         /*
1979                          * Report success and wake up. Here we abuse state_wq,
1980                          * i.e. wake up without state change, but we set cm_err.
1981                          */
1982                         flag_success_on_conn(con);
1983                         wake_up(&clt_path->state_wq);
1984                         return 0;
1985                 }
1986                 break;
1987         case RDMA_CM_EVENT_REJECTED:
1988                 cm_err = rtrs_rdma_conn_rejected(con, ev);
1989                 break;
1990         case RDMA_CM_EVENT_DISCONNECTED:
1991                 /* No message for disconnecting */
1992                 cm_err = -ECONNRESET;
1993                 break;
1994         case RDMA_CM_EVENT_CONNECT_ERROR:
1995         case RDMA_CM_EVENT_UNREACHABLE:
1996         case RDMA_CM_EVENT_ADDR_CHANGE:
1997         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
1998                 rtrs_wrn(s, "CM error (CM event: %s, err: %d)\n",
1999                          rdma_event_msg(ev->event), ev->status);
2000                 cm_err = -ECONNRESET;
2001                 break;
2002         case RDMA_CM_EVENT_ADDR_ERROR:
2003         case RDMA_CM_EVENT_ROUTE_ERROR:
2004                 rtrs_wrn(s, "CM error (CM event: %s, err: %d)\n",
2005                          rdma_event_msg(ev->event), ev->status);
2006                 cm_err = -EHOSTUNREACH;
2007                 break;
2008         case RDMA_CM_EVENT_DEVICE_REMOVAL:
2009                 /*
2010                  * Device removal is a special case.  Queue close and return 0.
2011                  */
2012                 rtrs_clt_close_conns(clt_path, false);
2013                 return 0;
2014         default:
2015                 rtrs_err(s, "Unexpected RDMA CM error (CM event: %s, err: %d)\n",
2016                          rdma_event_msg(ev->event), ev->status);
2017                 cm_err = -ECONNRESET;
2018                 break;
2019         }
2020
2021         if (cm_err) {
2022                 /*
2023                  * cm error makes sense only on connection establishing,
2024                  * in other cases we rely on normal procedure of reconnecting.
2025                  */
2026                 flag_error_on_conn(con, cm_err);
2027                 rtrs_rdma_error_recovery(con);
2028         }
2029
2030         return 0;
2031 }
2032
2033 static int create_cm(struct rtrs_clt_con *con)
2034 {
2035         struct rtrs_path *s = con->c.path;
2036         struct rtrs_clt_path *clt_path = to_clt_path(s);
2037         struct rdma_cm_id *cm_id;
2038         int err;
2039
2040         cm_id = rdma_create_id(&init_net, rtrs_clt_rdma_cm_handler, con,
2041                                clt_path->s.dst_addr.ss_family == AF_IB ?
2042                                RDMA_PS_IB : RDMA_PS_TCP, IB_QPT_RC);
2043         if (IS_ERR(cm_id)) {
2044                 err = PTR_ERR(cm_id);
2045                 rtrs_err(s, "Failed to create CM ID, err: %d\n", err);
2046
2047                 return err;
2048         }
2049         con->c.cm_id = cm_id;
2050         con->cm_err = 0;
2051         /* allow the port to be reused */
2052         err = rdma_set_reuseaddr(cm_id, 1);
2053         if (err != 0) {
2054                 rtrs_err(s, "Set address reuse failed, err: %d\n", err);
2055                 goto destroy_cm;
2056         }
2057         err = rdma_resolve_addr(cm_id, (struct sockaddr *)&clt_path->s.src_addr,
2058                                 (struct sockaddr *)&clt_path->s.dst_addr,
2059                                 RTRS_CONNECT_TIMEOUT_MS);
2060         if (err) {
2061                 rtrs_err(s, "Failed to resolve address, err: %d\n", err);
2062                 goto destroy_cm;
2063         }
2064         /*
2065          * Combine connection status and session events. This is needed
2066          * for waiting two possible cases: cm_err has something meaningful
2067          * or session state was really changed to error by device removal.
2068          */
2069         err = wait_event_interruptible_timeout(
2070                         clt_path->state_wq,
2071                         con->cm_err || clt_path->state != RTRS_CLT_CONNECTING,
2072                         msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS));
2073         if (err == 0 || err == -ERESTARTSYS) {
2074                 if (err == 0)
2075                         err = -ETIMEDOUT;
2076                 /* Timedout or interrupted */
2077                 goto errr;
2078         }
2079         if (con->cm_err < 0) {
2080                 err = con->cm_err;
2081                 goto errr;
2082         }
2083         if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTING) {
2084                 /* Device removal */
2085                 err = -ECONNABORTED;
2086                 goto errr;
2087         }
2088
2089         return 0;
2090
2091 errr:
2092         stop_cm(con);
2093         mutex_lock(&con->con_mutex);
2094         destroy_con_cq_qp(con);
2095         mutex_unlock(&con->con_mutex);
2096 destroy_cm:
2097         destroy_cm(con);
2098
2099         return err;
2100 }
2101
2102 static void rtrs_clt_path_up(struct rtrs_clt_path *clt_path)
2103 {
2104         struct rtrs_clt_sess *clt = clt_path->clt;
2105         int up;
2106
2107         /*
2108          * We can fire RECONNECTED event only when all paths were
2109          * connected on rtrs_clt_open(), then each was disconnected
2110          * and the first one connected again.  That's why this nasty
2111          * game with counter value.
2112          */
2113
2114         mutex_lock(&clt->paths_ev_mutex);
2115         up = ++clt->paths_up;
2116         /*
2117          * Here it is safe to access paths num directly since up counter
2118          * is greater than MAX_PATHS_NUM only while rtrs_clt_open() is
2119          * in progress, thus paths removals are impossible.
2120          */
2121         if (up > MAX_PATHS_NUM && up == MAX_PATHS_NUM + clt->paths_num)
2122                 clt->paths_up = clt->paths_num;
2123         else if (up == 1)
2124                 clt->link_ev(clt->priv, RTRS_CLT_LINK_EV_RECONNECTED);
2125         mutex_unlock(&clt->paths_ev_mutex);
2126
2127         /* Mark session as established */
2128         clt_path->established = true;
2129         clt_path->reconnect_attempts = 0;
2130         clt_path->stats->reconnects.successful_cnt++;
2131 }
2132
2133 static void rtrs_clt_path_down(struct rtrs_clt_path *clt_path)
2134 {
2135         struct rtrs_clt_sess *clt = clt_path->clt;
2136
2137         if (!clt_path->established)
2138                 return;
2139
2140         clt_path->established = false;
2141         mutex_lock(&clt->paths_ev_mutex);
2142         WARN_ON(!clt->paths_up);
2143         if (--clt->paths_up == 0)
2144                 clt->link_ev(clt->priv, RTRS_CLT_LINK_EV_DISCONNECTED);
2145         mutex_unlock(&clt->paths_ev_mutex);
2146 }
2147
2148 static void rtrs_clt_stop_and_destroy_conns(struct rtrs_clt_path *clt_path)
2149 {
2150         struct rtrs_clt_con *con;
2151         unsigned int cid;
2152
2153         WARN_ON(READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTED);
2154
2155         /*
2156          * Possible race with rtrs_clt_open(), when DEVICE_REMOVAL comes
2157          * exactly in between.  Start destroying after it finishes.
2158          */
2159         mutex_lock(&clt_path->init_mutex);
2160         mutex_unlock(&clt_path->init_mutex);
2161
2162         /*
2163          * All IO paths must observe !CONNECTED state before we
2164          * free everything.
2165          */
2166         synchronize_rcu();
2167
2168         rtrs_stop_hb(&clt_path->s);
2169
2170         /*
2171          * The order it utterly crucial: firstly disconnect and complete all
2172          * rdma requests with error (thus set in_use=false for requests),
2173          * then fail outstanding requests checking in_use for each, and
2174          * eventually notify upper layer about session disconnection.
2175          */
2176
2177         for (cid = 0; cid < clt_path->s.con_num; cid++) {
2178                 if (!clt_path->s.con[cid])
2179                         break;
2180                 con = to_clt_con(clt_path->s.con[cid]);
2181                 stop_cm(con);
2182         }
2183         fail_all_outstanding_reqs(clt_path);
2184         free_path_reqs(clt_path);
2185         rtrs_clt_path_down(clt_path);
2186
2187         /*
2188          * Wait for graceful shutdown, namely when peer side invokes
2189          * rdma_disconnect(). 'connected_cnt' is decremented only on
2190          * CM events, thus if other side had crashed and hb has detected
2191          * something is wrong, here we will stuck for exactly timeout ms,
2192          * since CM does not fire anything.  That is fine, we are not in
2193          * hurry.
2194          */
2195         wait_event_timeout(clt_path->state_wq,
2196                            !atomic_read(&clt_path->connected_cnt),
2197                            msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS));
2198
2199         for (cid = 0; cid < clt_path->s.con_num; cid++) {
2200                 if (!clt_path->s.con[cid])
2201                         break;
2202                 con = to_clt_con(clt_path->s.con[cid]);
2203                 mutex_lock(&con->con_mutex);
2204                 destroy_con_cq_qp(con);
2205                 mutex_unlock(&con->con_mutex);
2206                 destroy_cm(con);
2207                 destroy_con(con);
2208         }
2209 }
2210
2211 static inline bool xchg_paths(struct rtrs_clt_path __rcu **rcu_ppcpu_path,
2212                               struct rtrs_clt_path *clt_path,
2213                               struct rtrs_clt_path *next)
2214 {
2215         struct rtrs_clt_path **ppcpu_path;
2216
2217         /* Call cmpxchg() without sparse warnings */
2218         ppcpu_path = (typeof(ppcpu_path))rcu_ppcpu_path;
2219         return clt_path == cmpxchg(ppcpu_path, clt_path, next);
2220 }
2221
2222 static void rtrs_clt_remove_path_from_arr(struct rtrs_clt_path *clt_path)
2223 {
2224         struct rtrs_clt_sess *clt = clt_path->clt;
2225         struct rtrs_clt_path *next;
2226         bool wait_for_grace = false;
2227         int cpu;
2228
2229         mutex_lock(&clt->paths_mutex);
2230         list_del_rcu(&clt_path->s.entry);
2231
2232         /* Make sure everybody observes path removal. */
2233         synchronize_rcu();
2234
2235         /*
2236          * At this point nobody sees @sess in the list, but still we have
2237          * dangling pointer @pcpu_path which _can_ point to @sess.  Since
2238          * nobody can observe @sess in the list, we guarantee that IO path
2239          * will not assign @sess to @pcpu_path, i.e. @pcpu_path can be equal
2240          * to @sess, but can never again become @sess.
2241          */
2242
2243         /*
2244          * Decrement paths number only after grace period, because
2245          * caller of do_each_path() must firstly observe list without
2246          * path and only then decremented paths number.
2247          *
2248          * Otherwise there can be the following situation:
2249          *    o Two paths exist and IO is coming.
2250          *    o One path is removed:
2251          *      CPU#0                          CPU#1
2252          *      do_each_path():                rtrs_clt_remove_path_from_arr():
2253          *          path = get_next_path()
2254          *          ^^^                            list_del_rcu(path)
2255          *          [!CONNECTED path]              clt->paths_num--
2256          *                                              ^^^^^^^^^
2257          *          load clt->paths_num                 from 2 to 1
2258          *                    ^^^^^^^^^
2259          *                    sees 1
2260          *
2261          *      path is observed as !CONNECTED, but do_each_path() loop
2262          *      ends, because expression i < clt->paths_num is false.
2263          */
2264         clt->paths_num--;
2265
2266         /*
2267          * Get @next connection from current @sess which is going to be
2268          * removed.  If @sess is the last element, then @next is NULL.
2269          */
2270         rcu_read_lock();
2271         next = list_next_or_null_rr_rcu(&clt->paths_list, &clt_path->s.entry,
2272                                         typeof(*next), s.entry);
2273         rcu_read_unlock();
2274
2275         /*
2276          * @pcpu paths can still point to the path which is going to be
2277          * removed, so change the pointer manually.
2278          */
2279         for_each_possible_cpu(cpu) {
2280                 struct rtrs_clt_path __rcu **ppcpu_path;
2281
2282                 ppcpu_path = per_cpu_ptr(clt->pcpu_path, cpu);
2283                 if (rcu_dereference_protected(*ppcpu_path,
2284                         lockdep_is_held(&clt->paths_mutex)) != clt_path)
2285                         /*
2286                          * synchronize_rcu() was called just after deleting
2287                          * entry from the list, thus IO code path cannot
2288                          * change pointer back to the pointer which is going
2289                          * to be removed, we are safe here.
2290                          */
2291                         continue;
2292
2293                 /*
2294                  * We race with IO code path, which also changes pointer,
2295                  * thus we have to be careful not to overwrite it.
2296                  */
2297                 if (xchg_paths(ppcpu_path, clt_path, next))
2298                         /*
2299                          * @ppcpu_path was successfully replaced with @next,
2300                          * that means that someone could also pick up the
2301                          * @sess and dereferencing it right now, so wait for
2302                          * a grace period is required.
2303                          */
2304                         wait_for_grace = true;
2305         }
2306         if (wait_for_grace)
2307                 synchronize_rcu();
2308
2309         mutex_unlock(&clt->paths_mutex);
2310 }
2311
2312 static void rtrs_clt_add_path_to_arr(struct rtrs_clt_path *clt_path)
2313 {
2314         struct rtrs_clt_sess *clt = clt_path->clt;
2315
2316         mutex_lock(&clt->paths_mutex);
2317         clt->paths_num++;
2318
2319         list_add_tail_rcu(&clt_path->s.entry, &clt->paths_list);
2320         mutex_unlock(&clt->paths_mutex);
2321 }
2322
2323 static void rtrs_clt_close_work(struct work_struct *work)
2324 {
2325         struct rtrs_clt_path *clt_path;
2326
2327         clt_path = container_of(work, struct rtrs_clt_path, close_work);
2328
2329         cancel_delayed_work_sync(&clt_path->reconnect_dwork);
2330         rtrs_clt_stop_and_destroy_conns(clt_path);
2331         rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CLOSED, NULL);
2332 }
2333
2334 static int init_conns(struct rtrs_clt_path *clt_path)
2335 {
2336         unsigned int cid;
2337         int err;
2338
2339         /*
2340          * On every new session connections increase reconnect counter
2341          * to avoid clashes with previous sessions not yet closed
2342          * sessions on a server side.
2343          */
2344         clt_path->s.recon_cnt++;
2345
2346         /* Establish all RDMA connections  */
2347         for (cid = 0; cid < clt_path->s.con_num; cid++) {
2348                 err = create_con(clt_path, cid);
2349                 if (err)
2350                         goto destroy;
2351
2352                 err = create_cm(to_clt_con(clt_path->s.con[cid]));
2353                 if (err) {
2354                         destroy_con(to_clt_con(clt_path->s.con[cid]));
2355                         goto destroy;
2356                 }
2357         }
2358         err = alloc_path_reqs(clt_path);
2359         if (err)
2360                 goto destroy;
2361
2362         rtrs_start_hb(&clt_path->s);
2363
2364         return 0;
2365
2366 destroy:
2367         while (cid--) {
2368                 struct rtrs_clt_con *con = to_clt_con(clt_path->s.con[cid]);
2369
2370                 stop_cm(con);
2371
2372                 mutex_lock(&con->con_mutex);
2373                 destroy_con_cq_qp(con);
2374                 mutex_unlock(&con->con_mutex);
2375                 destroy_cm(con);
2376                 destroy_con(con);
2377         }
2378         /*
2379          * If we've never taken async path and got an error, say,
2380          * doing rdma_resolve_addr(), switch to CONNECTION_ERR state
2381          * manually to keep reconnecting.
2382          */
2383         rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CONNECTING_ERR, NULL);
2384
2385         return err;
2386 }
2387
2388 static void rtrs_clt_info_req_done(struct ib_cq *cq, struct ib_wc *wc)
2389 {
2390         struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context);
2391         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
2392         struct rtrs_iu *iu;
2393
2394         iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
2395         rtrs_iu_free(iu, clt_path->s.dev->ib_dev, 1);
2396
2397         if (wc->status != IB_WC_SUCCESS) {
2398                 rtrs_err(clt_path->clt, "Path info request send failed: %s\n",
2399                           ib_wc_status_msg(wc->status));
2400                 rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CONNECTING_ERR, NULL);
2401                 return;
2402         }
2403
2404         rtrs_clt_update_wc_stats(con);
2405 }
2406
2407 static int process_info_rsp(struct rtrs_clt_path *clt_path,
2408                             const struct rtrs_msg_info_rsp *msg)
2409 {
2410         unsigned int sg_cnt, total_len;
2411         int i, sgi;
2412
2413         sg_cnt = le16_to_cpu(msg->sg_cnt);
2414         if (!sg_cnt || (clt_path->queue_depth % sg_cnt)) {
2415                 rtrs_err(clt_path->clt,
2416                           "Incorrect sg_cnt %d, is not multiple\n",
2417                           sg_cnt);
2418                 return -EINVAL;
2419         }
2420
2421         /*
2422          * Check if IB immediate data size is enough to hold the mem_id and
2423          * the offset inside the memory chunk.
2424          */
2425         if ((ilog2(sg_cnt - 1) + 1) + (ilog2(clt_path->chunk_size - 1) + 1) >
2426             MAX_IMM_PAYL_BITS) {
2427                 rtrs_err(clt_path->clt,
2428                           "RDMA immediate size (%db) not enough to encode %d buffers of size %dB\n",
2429                           MAX_IMM_PAYL_BITS, sg_cnt, clt_path->chunk_size);
2430                 return -EINVAL;
2431         }
2432         total_len = 0;
2433         for (sgi = 0, i = 0; sgi < sg_cnt && i < clt_path->queue_depth; sgi++) {
2434                 const struct rtrs_sg_desc *desc = &msg->desc[sgi];
2435                 u32 len, rkey;
2436                 u64 addr;
2437
2438                 addr = le64_to_cpu(desc->addr);
2439                 rkey = le32_to_cpu(desc->key);
2440                 len  = le32_to_cpu(desc->len);
2441
2442                 total_len += len;
2443
2444                 if (!len || (len % clt_path->chunk_size)) {
2445                         rtrs_err(clt_path->clt, "Incorrect [%d].len %d\n",
2446                                   sgi,
2447                                   len);
2448                         return -EINVAL;
2449                 }
2450                 for ( ; len && i < clt_path->queue_depth; i++) {
2451                         clt_path->rbufs[i].addr = addr;
2452                         clt_path->rbufs[i].rkey = rkey;
2453
2454                         len  -= clt_path->chunk_size;
2455                         addr += clt_path->chunk_size;
2456                 }
2457         }
2458         /* Sanity check */
2459         if (sgi != sg_cnt || i != clt_path->queue_depth) {
2460                 rtrs_err(clt_path->clt,
2461                          "Incorrect sg vector, not fully mapped\n");
2462                 return -EINVAL;
2463         }
2464         if (total_len != clt_path->chunk_size * clt_path->queue_depth) {
2465                 rtrs_err(clt_path->clt, "Incorrect total_len %d\n", total_len);
2466                 return -EINVAL;
2467         }
2468
2469         return 0;
2470 }
2471
2472 static void rtrs_clt_info_rsp_done(struct ib_cq *cq, struct ib_wc *wc)
2473 {
2474         struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context);
2475         struct rtrs_clt_path *clt_path = to_clt_path(con->c.path);
2476         struct rtrs_msg_info_rsp *msg;
2477         enum rtrs_clt_state state;
2478         struct rtrs_iu *iu;
2479         size_t rx_sz;
2480         int err;
2481
2482         state = RTRS_CLT_CONNECTING_ERR;
2483
2484         WARN_ON(con->c.cid);
2485         iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
2486         if (wc->status != IB_WC_SUCCESS) {
2487                 rtrs_err(clt_path->clt, "Path info response recv failed: %s\n",
2488                           ib_wc_status_msg(wc->status));
2489                 goto out;
2490         }
2491         WARN_ON(wc->opcode != IB_WC_RECV);
2492
2493         if (wc->byte_len < sizeof(*msg)) {
2494                 rtrs_err(clt_path->clt, "Path info response is malformed: size %d\n",
2495                           wc->byte_len);
2496                 goto out;
2497         }
2498         ib_dma_sync_single_for_cpu(clt_path->s.dev->ib_dev, iu->dma_addr,
2499                                    iu->size, DMA_FROM_DEVICE);
2500         msg = iu->buf;
2501         if (le16_to_cpu(msg->type) != RTRS_MSG_INFO_RSP) {
2502                 rtrs_err(clt_path->clt, "Path info response is malformed: type %d\n",
2503                           le16_to_cpu(msg->type));
2504                 goto out;
2505         }
2506         rx_sz  = sizeof(*msg);
2507         rx_sz += sizeof(msg->desc[0]) * le16_to_cpu(msg->sg_cnt);
2508         if (wc->byte_len < rx_sz) {
2509                 rtrs_err(clt_path->clt, "Path info response is malformed: size %d\n",
2510                           wc->byte_len);
2511                 goto out;
2512         }
2513         err = process_info_rsp(clt_path, msg);
2514         if (err)
2515                 goto out;
2516
2517         err = post_recv_path(clt_path);
2518         if (err)
2519                 goto out;
2520
2521         state = RTRS_CLT_CONNECTED;
2522
2523 out:
2524         rtrs_clt_update_wc_stats(con);
2525         rtrs_iu_free(iu, clt_path->s.dev->ib_dev, 1);
2526         rtrs_clt_change_state_get_old(clt_path, state, NULL);
2527 }
2528
2529 static int rtrs_send_path_info(struct rtrs_clt_path *clt_path)
2530 {
2531         struct rtrs_clt_con *usr_con = to_clt_con(clt_path->s.con[0]);
2532         struct rtrs_msg_info_req *msg;
2533         struct rtrs_iu *tx_iu, *rx_iu;
2534         size_t rx_sz;
2535         int err;
2536
2537         rx_sz  = sizeof(struct rtrs_msg_info_rsp);
2538         rx_sz += sizeof(struct rtrs_sg_desc) * clt_path->queue_depth;
2539
2540         tx_iu = rtrs_iu_alloc(1, sizeof(struct rtrs_msg_info_req), GFP_KERNEL,
2541                                clt_path->s.dev->ib_dev, DMA_TO_DEVICE,
2542                                rtrs_clt_info_req_done);
2543         rx_iu = rtrs_iu_alloc(1, rx_sz, GFP_KERNEL, clt_path->s.dev->ib_dev,
2544                                DMA_FROM_DEVICE, rtrs_clt_info_rsp_done);
2545         if (!tx_iu || !rx_iu) {
2546                 err = -ENOMEM;
2547                 goto out;
2548         }
2549         /* Prepare for getting info response */
2550         err = rtrs_iu_post_recv(&usr_con->c, rx_iu);
2551         if (err) {
2552                 rtrs_err(clt_path->clt, "rtrs_iu_post_recv(), err: %d\n", err);
2553                 goto out;
2554         }
2555         rx_iu = NULL;
2556
2557         msg = tx_iu->buf;
2558         msg->type = cpu_to_le16(RTRS_MSG_INFO_REQ);
2559         memcpy(msg->pathname, clt_path->s.sessname, sizeof(msg->pathname));
2560
2561         ib_dma_sync_single_for_device(clt_path->s.dev->ib_dev,
2562                                       tx_iu->dma_addr,
2563                                       tx_iu->size, DMA_TO_DEVICE);
2564
2565         /* Send info request */
2566         err = rtrs_iu_post_send(&usr_con->c, tx_iu, sizeof(*msg), NULL);
2567         if (err) {
2568                 rtrs_err(clt_path->clt, "rtrs_iu_post_send(), err: %d\n", err);
2569                 goto out;
2570         }
2571         tx_iu = NULL;
2572
2573         /* Wait for state change */
2574         wait_event_interruptible_timeout(clt_path->state_wq,
2575                                          clt_path->state != RTRS_CLT_CONNECTING,
2576                                          msecs_to_jiffies(
2577                                                  RTRS_CONNECT_TIMEOUT_MS));
2578         if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED) {
2579                 if (READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTING_ERR)
2580                         err = -ECONNRESET;
2581                 else
2582                         err = -ETIMEDOUT;
2583         }
2584
2585 out:
2586         if (tx_iu)
2587                 rtrs_iu_free(tx_iu, clt_path->s.dev->ib_dev, 1);
2588         if (rx_iu)
2589                 rtrs_iu_free(rx_iu, clt_path->s.dev->ib_dev, 1);
2590         if (err)
2591                 /* If we've never taken async path because of malloc problems */
2592                 rtrs_clt_change_state_get_old(clt_path,
2593                                               RTRS_CLT_CONNECTING_ERR, NULL);
2594
2595         return err;
2596 }
2597
2598 /**
2599  * init_path() - establishes all path connections and does handshake
2600  * @clt_path: client path.
2601  * In case of error full close or reconnect procedure should be taken,
2602  * because reconnect or close async works can be started.
2603  */
2604 static int init_path(struct rtrs_clt_path *clt_path)
2605 {
2606         int err;
2607         char str[NAME_MAX];
2608         struct rtrs_addr path = {
2609                 .src = &clt_path->s.src_addr,
2610                 .dst = &clt_path->s.dst_addr,
2611         };
2612
2613         rtrs_addr_to_str(&path, str, sizeof(str));
2614
2615         mutex_lock(&clt_path->init_mutex);
2616         err = init_conns(clt_path);
2617         if (err) {
2618                 rtrs_err(clt_path->clt,
2619                          "init_conns() failed: err=%d path=%s [%s:%u]\n", err,
2620                          str, clt_path->hca_name, clt_path->hca_port);
2621                 goto out;
2622         }
2623         err = rtrs_send_path_info(clt_path);
2624         if (err) {
2625                 rtrs_err(clt_path->clt,
2626                          "rtrs_send_path_info() failed: err=%d path=%s [%s:%u]\n",
2627                          err, str, clt_path->hca_name, clt_path->hca_port);
2628                 goto out;
2629         }
2630         rtrs_clt_path_up(clt_path);
2631 out:
2632         mutex_unlock(&clt_path->init_mutex);
2633
2634         return err;
2635 }
2636
2637 static void rtrs_clt_reconnect_work(struct work_struct *work)
2638 {
2639         struct rtrs_clt_path *clt_path;
2640         struct rtrs_clt_sess *clt;
2641         unsigned int delay_ms;
2642         int err;
2643
2644         clt_path = container_of(to_delayed_work(work), struct rtrs_clt_path,
2645                                 reconnect_dwork);
2646         clt = clt_path->clt;
2647
2648         if (READ_ONCE(clt_path->state) != RTRS_CLT_RECONNECTING)
2649                 return;
2650
2651         if (clt_path->reconnect_attempts >= clt->max_reconnect_attempts) {
2652                 /* Close a path completely if max attempts is reached */
2653                 rtrs_clt_close_conns(clt_path, false);
2654                 return;
2655         }
2656         clt_path->reconnect_attempts++;
2657
2658         /* Stop everything */
2659         rtrs_clt_stop_and_destroy_conns(clt_path);
2660         msleep(RTRS_RECONNECT_BACKOFF);
2661         if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CONNECTING, NULL)) {
2662                 err = init_path(clt_path);
2663                 if (err)
2664                         goto reconnect_again;
2665         }
2666
2667         return;
2668
2669 reconnect_again:
2670         if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_RECONNECTING, NULL)) {
2671                 clt_path->stats->reconnects.fail_cnt++;
2672                 delay_ms = clt->reconnect_delay_sec * 1000;
2673                 queue_delayed_work(rtrs_wq, &clt_path->reconnect_dwork,
2674                                    msecs_to_jiffies(delay_ms +
2675                                                     prandom_u32() %
2676                                                     RTRS_RECONNECT_SEED));
2677         }
2678 }
2679
2680 static void rtrs_clt_dev_release(struct device *dev)
2681 {
2682         struct rtrs_clt_sess *clt = container_of(dev, struct rtrs_clt_sess,
2683                                                  dev);
2684
2685         kfree(clt);
2686 }
2687
2688 static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
2689                                   u16 port, size_t pdu_sz, void *priv,
2690                                   void  (*link_ev)(void *priv,
2691                                                    enum rtrs_clt_link_ev ev),
2692                                   unsigned int reconnect_delay_sec,
2693                                   unsigned int max_reconnect_attempts)
2694 {
2695         struct rtrs_clt_sess *clt;
2696         int err;
2697
2698         if (!paths_num || paths_num > MAX_PATHS_NUM)
2699                 return ERR_PTR(-EINVAL);
2700
2701         if (strlen(sessname) >= sizeof(clt->sessname))
2702                 return ERR_PTR(-EINVAL);
2703
2704         clt = kzalloc(sizeof(*clt), GFP_KERNEL);
2705         if (!clt)
2706                 return ERR_PTR(-ENOMEM);
2707
2708         clt->pcpu_path = alloc_percpu(typeof(*clt->pcpu_path));
2709         if (!clt->pcpu_path) {
2710                 kfree(clt);
2711                 return ERR_PTR(-ENOMEM);
2712         }
2713
2714         uuid_gen(&clt->paths_uuid);
2715         INIT_LIST_HEAD_RCU(&clt->paths_list);
2716         clt->paths_num = paths_num;
2717         clt->paths_up = MAX_PATHS_NUM;
2718         clt->port = port;
2719         clt->pdu_sz = pdu_sz;
2720         clt->max_segments = RTRS_MAX_SEGMENTS;
2721         clt->reconnect_delay_sec = reconnect_delay_sec;
2722         clt->max_reconnect_attempts = max_reconnect_attempts;
2723         clt->priv = priv;
2724         clt->link_ev = link_ev;
2725         clt->mp_policy = MP_POLICY_MIN_INFLIGHT;
2726         strscpy(clt->sessname, sessname, sizeof(clt->sessname));
2727         init_waitqueue_head(&clt->permits_wait);
2728         mutex_init(&clt->paths_ev_mutex);
2729         mutex_init(&clt->paths_mutex);
2730
2731         clt->dev.class = rtrs_clt_dev_class;
2732         clt->dev.release = rtrs_clt_dev_release;
2733         err = dev_set_name(&clt->dev, "%s", sessname);
2734         if (err)
2735                 goto err;
2736         /*
2737          * Suppress user space notification until
2738          * sysfs files are created
2739          */
2740         dev_set_uevent_suppress(&clt->dev, true);
2741         err = device_register(&clt->dev);
2742         if (err) {
2743                 put_device(&clt->dev);
2744                 goto err;
2745         }
2746
2747         clt->kobj_paths = kobject_create_and_add("paths", &clt->dev.kobj);
2748         if (!clt->kobj_paths) {
2749                 err = -ENOMEM;
2750                 goto err_dev;
2751         }
2752         err = rtrs_clt_create_sysfs_root_files(clt);
2753         if (err) {
2754                 kobject_del(clt->kobj_paths);
2755                 kobject_put(clt->kobj_paths);
2756                 goto err_dev;
2757         }
2758         dev_set_uevent_suppress(&clt->dev, false);
2759         kobject_uevent(&clt->dev.kobj, KOBJ_ADD);
2760
2761         return clt;
2762 err_dev:
2763         device_unregister(&clt->dev);
2764 err:
2765         free_percpu(clt->pcpu_path);
2766         kfree(clt);
2767         return ERR_PTR(err);
2768 }
2769
2770 static void free_clt(struct rtrs_clt_sess *clt)
2771 {
2772         free_permits(clt);
2773         free_percpu(clt->pcpu_path);
2774         mutex_destroy(&clt->paths_ev_mutex);
2775         mutex_destroy(&clt->paths_mutex);
2776         /* release callback will free clt in last put */
2777         device_unregister(&clt->dev);
2778 }
2779
2780 /**
2781  * rtrs_clt_open() - Open a path to an RTRS server
2782  * @ops: holds the link event callback and the private pointer.
2783  * @sessname: name of the session
2784  * @paths: Paths to be established defined by their src and dst addresses
2785  * @paths_num: Number of elements in the @paths array
2786  * @port: port to be used by the RTRS session
2787  * @pdu_sz: Size of extra payload which can be accessed after permit allocation.
2788  * @reconnect_delay_sec: time between reconnect tries
2789  * @max_reconnect_attempts: Number of times to reconnect on error before giving
2790  *                          up, 0 for * disabled, -1 for forever
2791  * @nr_poll_queues: number of polling mode connection using IB_POLL_DIRECT flag
2792  *
2793  * Starts session establishment with the rtrs_server. The function can block
2794  * up to ~2000ms before it returns.
2795  *
2796  * Return a valid pointer on success otherwise PTR_ERR.
2797  */
2798 struct rtrs_clt_sess *rtrs_clt_open(struct rtrs_clt_ops *ops,
2799                                  const char *pathname,
2800                                  const struct rtrs_addr *paths,
2801                                  size_t paths_num, u16 port,
2802                                  size_t pdu_sz, u8 reconnect_delay_sec,
2803                                  s16 max_reconnect_attempts, u32 nr_poll_queues)
2804 {
2805         struct rtrs_clt_path *clt_path, *tmp;
2806         struct rtrs_clt_sess *clt;
2807         int err, i;
2808
2809         if (strchr(pathname, '/') || strchr(pathname, '.')) {
2810                 pr_err("pathname cannot contain / and .\n");
2811                 err = -EINVAL;
2812                 goto out;
2813         }
2814
2815         clt = alloc_clt(pathname, paths_num, port, pdu_sz, ops->priv,
2816                         ops->link_ev,
2817                         reconnect_delay_sec,
2818                         max_reconnect_attempts);
2819         if (IS_ERR(clt)) {
2820                 err = PTR_ERR(clt);
2821                 goto out;
2822         }
2823         for (i = 0; i < paths_num; i++) {
2824                 struct rtrs_clt_path *clt_path;
2825
2826                 clt_path = alloc_path(clt, &paths[i], nr_cpu_ids,
2827                                   nr_poll_queues);
2828                 if (IS_ERR(clt_path)) {
2829                         err = PTR_ERR(clt_path);
2830                         goto close_all_path;
2831                 }
2832                 if (!i)
2833                         clt_path->for_new_clt = 1;
2834                 list_add_tail_rcu(&clt_path->s.entry, &clt->paths_list);
2835
2836                 err = init_path(clt_path);
2837                 if (err) {
2838                         list_del_rcu(&clt_path->s.entry);
2839                         rtrs_clt_close_conns(clt_path, true);
2840                         free_percpu(clt_path->stats->pcpu_stats);
2841                         kfree(clt_path->stats);
2842                         free_path(clt_path);
2843                         goto close_all_path;
2844                 }
2845
2846                 err = rtrs_clt_create_path_files(clt_path);
2847                 if (err) {
2848                         list_del_rcu(&clt_path->s.entry);
2849                         rtrs_clt_close_conns(clt_path, true);
2850                         free_percpu(clt_path->stats->pcpu_stats);
2851                         kfree(clt_path->stats);
2852                         free_path(clt_path);
2853                         goto close_all_path;
2854                 }
2855         }
2856         err = alloc_permits(clt);
2857         if (err)
2858                 goto close_all_path;
2859
2860         return clt;
2861
2862 close_all_path:
2863         list_for_each_entry_safe(clt_path, tmp, &clt->paths_list, s.entry) {
2864                 rtrs_clt_destroy_path_files(clt_path, NULL);
2865                 rtrs_clt_close_conns(clt_path, true);
2866                 kobject_put(&clt_path->kobj);
2867         }
2868         rtrs_clt_destroy_sysfs_root(clt);
2869         free_clt(clt);
2870
2871 out:
2872         return ERR_PTR(err);
2873 }
2874 EXPORT_SYMBOL(rtrs_clt_open);
2875
2876 /**
2877  * rtrs_clt_close() - Close a path
2878  * @clt: Session handle. Session is freed upon return.
2879  */
2880 void rtrs_clt_close(struct rtrs_clt_sess *clt)
2881 {
2882         struct rtrs_clt_path *clt_path, *tmp;
2883
2884         /* Firstly forbid sysfs access */
2885         rtrs_clt_destroy_sysfs_root(clt);
2886
2887         /* Now it is safe to iterate over all paths without locks */
2888         list_for_each_entry_safe(clt_path, tmp, &clt->paths_list, s.entry) {
2889                 rtrs_clt_close_conns(clt_path, true);
2890                 rtrs_clt_destroy_path_files(clt_path, NULL);
2891                 kobject_put(&clt_path->kobj);
2892         }
2893         free_clt(clt);
2894 }
2895 EXPORT_SYMBOL(rtrs_clt_close);
2896
2897 int rtrs_clt_reconnect_from_sysfs(struct rtrs_clt_path *clt_path)
2898 {
2899         enum rtrs_clt_state old_state;
2900         int err = -EBUSY;
2901         bool changed;
2902
2903         changed = rtrs_clt_change_state_get_old(clt_path,
2904                                                  RTRS_CLT_RECONNECTING,
2905                                                  &old_state);
2906         if (changed) {
2907                 clt_path->reconnect_attempts = 0;
2908                 queue_delayed_work(rtrs_wq, &clt_path->reconnect_dwork, 0);
2909         }
2910         if (changed || old_state == RTRS_CLT_RECONNECTING) {
2911                 /*
2912                  * flush_delayed_work() queues pending work for immediate
2913                  * execution, so do the flush if we have queued something
2914                  * right now or work is pending.
2915                  */
2916                 flush_delayed_work(&clt_path->reconnect_dwork);
2917                 err = (READ_ONCE(clt_path->state) ==
2918                        RTRS_CLT_CONNECTED ? 0 : -ENOTCONN);
2919         }
2920
2921         return err;
2922 }
2923
2924 int rtrs_clt_remove_path_from_sysfs(struct rtrs_clt_path *clt_path,
2925                                      const struct attribute *sysfs_self)
2926 {
2927         enum rtrs_clt_state old_state;
2928         bool changed;
2929
2930         /*
2931          * Continue stopping path till state was changed to DEAD or
2932          * state was observed as DEAD:
2933          * 1. State was changed to DEAD - we were fast and nobody
2934          *    invoked rtrs_clt_reconnect(), which can again start
2935          *    reconnecting.
2936          * 2. State was observed as DEAD - we have someone in parallel
2937          *    removing the path.
2938          */
2939         do {
2940                 rtrs_clt_close_conns(clt_path, true);
2941                 changed = rtrs_clt_change_state_get_old(clt_path,
2942                                                         RTRS_CLT_DEAD,
2943                                                         &old_state);
2944         } while (!changed && old_state != RTRS_CLT_DEAD);
2945
2946         if (changed) {
2947                 rtrs_clt_remove_path_from_arr(clt_path);
2948                 rtrs_clt_destroy_path_files(clt_path, sysfs_self);
2949                 kobject_put(&clt_path->kobj);
2950         }
2951
2952         return 0;
2953 }
2954
2955 void rtrs_clt_set_max_reconnect_attempts(struct rtrs_clt_sess *clt, int value)
2956 {
2957         clt->max_reconnect_attempts = (unsigned int)value;
2958 }
2959
2960 int rtrs_clt_get_max_reconnect_attempts(const struct rtrs_clt_sess *clt)
2961 {
2962         return (int)clt->max_reconnect_attempts;
2963 }
2964
2965 /**
2966  * rtrs_clt_request() - Request data transfer to/from server via RDMA.
2967  *
2968  * @dir:        READ/WRITE
2969  * @ops:        callback function to be called as confirmation, and the pointer.
2970  * @clt:        Session
2971  * @permit:     Preallocated permit
2972  * @vec:        Message that is sent to server together with the request.
2973  *              Sum of len of all @vec elements limited to <= IO_MSG_SIZE.
2974  *              Since the msg is copied internally it can be allocated on stack.
2975  * @nr:         Number of elements in @vec.
2976  * @data_len:   length of data sent to/from server
2977  * @sg:         Pages to be sent/received to/from server.
2978  * @sg_cnt:     Number of elements in the @sg
2979  *
2980  * Return:
2981  * 0:           Success
2982  * <0:          Error
2983  *
2984  * On dir=READ rtrs client will request a data transfer from Server to client.
2985  * The data that the server will respond with will be stored in @sg when
2986  * the user receives an %RTRS_CLT_RDMA_EV_RDMA_REQUEST_WRITE_COMPL event.
2987  * On dir=WRITE rtrs client will rdma write data in sg to server side.
2988  */
2989 int rtrs_clt_request(int dir, struct rtrs_clt_req_ops *ops,
2990                      struct rtrs_clt_sess *clt, struct rtrs_permit *permit,
2991                      const struct kvec *vec, size_t nr, size_t data_len,
2992                      struct scatterlist *sg, unsigned int sg_cnt)
2993 {
2994         struct rtrs_clt_io_req *req;
2995         struct rtrs_clt_path *clt_path;
2996
2997         enum dma_data_direction dma_dir;
2998         int err = -ECONNABORTED, i;
2999         size_t usr_len, hdr_len;
3000         struct path_it it;
3001
3002         /* Get kvec length */
3003         for (i = 0, usr_len = 0; i < nr; i++)
3004                 usr_len += vec[i].iov_len;
3005
3006         if (dir == READ) {
3007                 hdr_len = sizeof(struct rtrs_msg_rdma_read) +
3008                           sg_cnt * sizeof(struct rtrs_sg_desc);
3009                 dma_dir = DMA_FROM_DEVICE;
3010         } else {
3011                 hdr_len = sizeof(struct rtrs_msg_rdma_write);
3012                 dma_dir = DMA_TO_DEVICE;
3013         }
3014
3015         rcu_read_lock();
3016         for (path_it_init(&it, clt);
3017              (clt_path = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) {
3018                 if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
3019                         continue;
3020
3021                 if (usr_len + hdr_len > clt_path->max_hdr_size) {
3022                         rtrs_wrn_rl(clt_path->clt,
3023                                      "%s request failed, user message size is %zu and header length %zu, but max size is %u\n",
3024                                      dir == READ ? "Read" : "Write",
3025                                      usr_len, hdr_len, clt_path->max_hdr_size);
3026                         err = -EMSGSIZE;
3027                         break;
3028                 }
3029                 req = rtrs_clt_get_req(clt_path, ops->conf_fn, permit, ops->priv,
3030                                        vec, usr_len, sg, sg_cnt, data_len,
3031                                        dma_dir);
3032                 if (dir == READ)
3033                         err = rtrs_clt_read_req(req);
3034                 else
3035                         err = rtrs_clt_write_req(req);
3036                 if (err) {
3037                         req->in_use = false;
3038                         continue;
3039                 }
3040                 /* Success path */
3041                 break;
3042         }
3043         path_it_deinit(&it);
3044         rcu_read_unlock();
3045
3046         return err;
3047 }
3048 EXPORT_SYMBOL(rtrs_clt_request);
3049
3050 int rtrs_clt_rdma_cq_direct(struct rtrs_clt_sess *clt, unsigned int index)
3051 {
3052         /* If no path, return -1 for block layer not to try again */
3053         int cnt = -1;
3054         struct rtrs_con *con;
3055         struct rtrs_clt_path *clt_path;
3056         struct path_it it;
3057
3058         rcu_read_lock();
3059         for (path_it_init(&it, clt);
3060              (clt_path = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) {
3061                 if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED)
3062                         continue;
3063
3064                 con = clt_path->s.con[index + 1];
3065                 cnt = ib_process_cq_direct(con->cq, -1);
3066                 if (cnt)
3067                         break;
3068         }
3069         path_it_deinit(&it);
3070         rcu_read_unlock();
3071
3072         return cnt;
3073 }
3074 EXPORT_SYMBOL(rtrs_clt_rdma_cq_direct);
3075
3076 /**
3077  * rtrs_clt_query() - queries RTRS session attributes
3078  *@clt: session pointer
3079  *@attr: query results for session attributes.
3080  * Returns:
3081  *    0 on success
3082  *    -ECOMM            no connection to the server
3083  */
3084 int rtrs_clt_query(struct rtrs_clt_sess *clt, struct rtrs_attrs *attr)
3085 {
3086         if (!rtrs_clt_is_connected(clt))
3087                 return -ECOMM;
3088
3089         attr->queue_depth      = clt->queue_depth;
3090         attr->max_segments     = clt->max_segments;
3091         /* Cap max_io_size to min of remote buffer size and the fr pages */
3092         attr->max_io_size = min_t(int, clt->max_io_size,
3093                                   clt->max_segments * SZ_4K);
3094
3095         return 0;
3096 }
3097 EXPORT_SYMBOL(rtrs_clt_query);
3098
3099 int rtrs_clt_create_path_from_sysfs(struct rtrs_clt_sess *clt,
3100                                      struct rtrs_addr *addr)
3101 {
3102         struct rtrs_clt_path *clt_path;
3103         int err;
3104
3105         clt_path = alloc_path(clt, addr, nr_cpu_ids, 0);
3106         if (IS_ERR(clt_path))
3107                 return PTR_ERR(clt_path);
3108
3109         mutex_lock(&clt->paths_mutex);
3110         if (clt->paths_num == 0) {
3111                 /*
3112                  * When all the paths are removed for a session,
3113                  * the addition of the first path is like a new session for
3114                  * the storage server
3115                  */
3116                 clt_path->for_new_clt = 1;
3117         }
3118
3119         mutex_unlock(&clt->paths_mutex);
3120
3121         /*
3122          * It is totally safe to add path in CONNECTING state: coming
3123          * IO will never grab it.  Also it is very important to add
3124          * path before init, since init fires LINK_CONNECTED event.
3125          */
3126         rtrs_clt_add_path_to_arr(clt_path);
3127
3128         err = init_path(clt_path);
3129         if (err)
3130                 goto close_path;
3131
3132         err = rtrs_clt_create_path_files(clt_path);
3133         if (err)
3134                 goto close_path;
3135
3136         return 0;
3137
3138 close_path:
3139         rtrs_clt_remove_path_from_arr(clt_path);
3140         rtrs_clt_close_conns(clt_path, true);
3141         free_percpu(clt_path->stats->pcpu_stats);
3142         kfree(clt_path->stats);
3143         free_path(clt_path);
3144
3145         return err;
3146 }
3147
3148 static int rtrs_clt_ib_dev_init(struct rtrs_ib_dev *dev)
3149 {
3150         if (!(dev->ib_dev->attrs.device_cap_flags &
3151               IB_DEVICE_MEM_MGT_EXTENSIONS)) {
3152                 pr_err("Memory registrations not supported.\n");
3153                 return -ENOTSUPP;
3154         }
3155
3156         return 0;
3157 }
3158
3159 static const struct rtrs_rdma_dev_pd_ops dev_pd_ops = {
3160         .init = rtrs_clt_ib_dev_init
3161 };
3162
3163 static int __init rtrs_client_init(void)
3164 {
3165         rtrs_rdma_dev_pd_init(0, &dev_pd);
3166
3167         rtrs_clt_dev_class = class_create(THIS_MODULE, "rtrs-client");
3168         if (IS_ERR(rtrs_clt_dev_class)) {
3169                 pr_err("Failed to create rtrs-client dev class\n");
3170                 return PTR_ERR(rtrs_clt_dev_class);
3171         }
3172         rtrs_wq = alloc_workqueue("rtrs_client_wq", 0, 0);
3173         if (!rtrs_wq) {
3174                 class_destroy(rtrs_clt_dev_class);
3175                 return -ENOMEM;
3176         }
3177
3178         return 0;
3179 }
3180
3181 static void __exit rtrs_client_exit(void)
3182 {
3183         destroy_workqueue(rtrs_wq);
3184         class_destroy(rtrs_clt_dev_class);
3185         rtrs_rdma_dev_pd_deinit(&dev_pd);
3186 }
3187
3188 module_init(rtrs_client_init);
3189 module_exit(rtrs_client_exit);