net/smc/smc_wr.c

   1 /*
   2  * Shared Memory Communications over RDMA (SMC-R) and RoCE
   3  *
   4  * Work Requests exploiting Infiniband API
   5  *
   6  * Work requests (WR) of type ib_post_send or ib_post_recv respectively
   7  * are submitted to either RC SQ or RC RQ respectively
   8  * (reliably connected send/receive queue)
   9  * and become work queue entries (WQEs).
  10  * While an SQ WR/WQE is pending, we track it until transmission completion.
  11  * Through a send or receive completion queue (CQ) respectively,
  12  * we get completion queue entries (CQEs) [aka work completions (WCs)].
  13  * Since the CQ callback is called from IRQ context, we split work by using
  14  * bottom halves implemented by tasklets.
  15  *
  16  * SMC uses this to exchange LLC (link layer control)
  17  * and CDC (connection data control) messages.
  18  *
  19  * Copyright IBM Corp. 2016
  20  *
  21  * Author(s):  Steffen Maier <[email protected]>
  22  */
  23
  24 #include <linux/atomic.h>
  25 #include <linux/hashtable.h>
  26 #include <linux/wait.h>
  27 #include <rdma/ib_verbs.h>
  28 #include <asm/div64.h>
  29
  30 #include "smc.h"
  31 #include "smc_wr.h"
  32
  33 #define SMC_WR_MAX_POLL_CQE 10  /* max. # of compl. queue elements in 1 poll */
  34
  35 #define SMC_WR_RX_HASH_BITS 4
  36 static DEFINE_HASHTABLE(smc_wr_rx_hash, SMC_WR_RX_HASH_BITS);
  37 static DEFINE_SPINLOCK(smc_wr_rx_hash_lock);
  38
  39 struct smc_wr_tx_pend { /* control data for a pending send request */
  40         u64                     wr_id;          /* work request id sent */
  41         smc_wr_tx_handler       handler;
  42         enum ib_wc_status       wc_status;      /* CQE status */
  43         struct smc_link         *link;
  44         u32                     idx;
  45         struct smc_wr_tx_pend_priv priv;
  46 };
  47
  48 /******************************** send queue *********************************/
  49
  50 /*------------------------------- completion --------------------------------*/
  51
  52 static inline int smc_wr_tx_find_pending_index(struct smc_link *link, u64 wr_id)
  53 {
  54         u32 i;
  55
  56         for (i = 0; i < link->wr_tx_cnt; i++) {
  57                 if (link->wr_tx_pends[i].wr_id == wr_id)
  58                         return i;
  59         }
  60         return link->wr_tx_cnt;
  61 }
  62
  63 static inline void smc_wr_tx_process_cqe(struct ib_wc *wc)
  64 {
  65         struct smc_wr_tx_pend pnd_snd;
  66         struct smc_link *link;
  67         u32 pnd_snd_idx;
  68         int i;
  69
  70         link = wc->qp->qp_context;
  71         pnd_snd_idx = smc_wr_tx_find_pending_index(link, wc->wr_id);
  72         if (pnd_snd_idx == link->wr_tx_cnt)
  73                 return;
  74         link->wr_tx_pends[pnd_snd_idx].wc_status = wc->status;
  75         memcpy(&pnd_snd, &link->wr_tx_pends[pnd_snd_idx], sizeof(pnd_snd));
  76         /* clear the full struct smc_wr_tx_pend including .priv */
  77         memset(&link->wr_tx_pends[pnd_snd_idx], 0,
  78                sizeof(link->wr_tx_pends[pnd_snd_idx]));
  79         memset(&link->wr_tx_bufs[pnd_snd_idx], 0,
  80                sizeof(link->wr_tx_bufs[pnd_snd_idx]));
  81         if (!test_and_clear_bit(pnd_snd_idx, link->wr_tx_mask))
  82                 return;
  83         if (wc->status) {
  84                 struct smc_link_group *lgr;
  85
  86                 for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
  87                         /* clear full struct smc_wr_tx_pend including .priv */
  88                         memset(&link->wr_tx_pends[i], 0,
  89                                sizeof(link->wr_tx_pends[i]));
  90                         memset(&link->wr_tx_bufs[i], 0,
  91                                sizeof(link->wr_tx_bufs[i]));
  92                         clear_bit(i, link->wr_tx_mask);
  93                 }
  94                 /* terminate connections of this link group abnormally */
  95                 lgr = container_of(link, struct smc_link_group,
  96                                    lnk[SMC_SINGLE_LINK]);
  97                 smc_lgr_terminate(lgr);
  98         }
  99         if (pnd_snd.handler)
 100                 pnd_snd.handler(&pnd_snd.priv, link, wc->status);
 101         wake_up(&link->wr_tx_wait);
 102 }
 103
 104 static void smc_wr_tx_tasklet_fn(unsigned long data)
 105 {
 106         struct smc_ib_device *dev = (struct smc_ib_device *)data;
 107         struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
 108         int i = 0, rc;
 109         int polled = 0;
 110
 111 again:
 112         polled++;
 113         do {
 114                 rc = ib_poll_cq(dev->roce_cq_send, SMC_WR_MAX_POLL_CQE, wc);
 115                 if (polled == 1) {
 116                         ib_req_notify_cq(dev->roce_cq_send,
 117                                          IB_CQ_NEXT_COMP |
 118                                          IB_CQ_REPORT_MISSED_EVENTS);
 119                 }
 120                 if (!rc)
 121                         break;
 122                 for (i = 0; i < rc; i++)
 123                         smc_wr_tx_process_cqe(&wc[i]);
 124         } while (rc > 0);
 125         if (polled == 1)
 126                 goto again;
 127 }
 128
 129 void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
 130 {
 131         struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
 132
 133         tasklet_schedule(&dev->send_tasklet);
 134 }
 135
 136 /*---------------------------- request submission ---------------------------*/
 137
 138 static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
 139 {
 140         *idx = link->wr_tx_cnt;
 141         for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
 142                 if (!test_and_set_bit(*idx, link->wr_tx_mask))
 143                         return 0;
 144         }
 145         *idx = link->wr_tx_cnt;
 146         return -EBUSY;
 147 }
 148
 149 /**
 150  * smc_wr_tx_get_free_slot() - returns buffer for message assembly,
 151  *                      and sets info for pending transmit tracking
 152  * @link:               Pointer to smc_link used to later send the message.
 153  * @handler:            Send completion handler function pointer.
 154  * @wr_buf:             Out value returns pointer to message buffer.
 155  * @wr_pend_priv:       Out value returns pointer serving as handler context.
 156  *
 157  * Return: 0 on success, or -errno on error.
 158  */
 159 int smc_wr_tx_get_free_slot(struct smc_link *link,
 160                             smc_wr_tx_handler handler,
 161                             struct smc_wr_buf **wr_buf,
 162                             struct smc_wr_tx_pend_priv **wr_pend_priv)
 163 {
 164         struct smc_wr_tx_pend *wr_pend;
 165         struct ib_send_wr *wr_ib;
 166         u64 wr_id;
 167         u32 idx;
 168         int rc;
 169
 170         *wr_buf = NULL;
 171         *wr_pend_priv = NULL;
 172         if (in_softirq()) {
 173                 rc = smc_wr_tx_get_free_slot_index(link, &idx);
 174                 if (rc)
 175                         return rc;
 176         } else {
 177                 rc = wait_event_interruptible_timeout(
 178                         link->wr_tx_wait,
 179                         (smc_wr_tx_get_free_slot_index(link, &idx) != -EBUSY),
 180                         SMC_WR_TX_WAIT_FREE_SLOT_TIME);
 181                 if (!rc) {
 182                         /* timeout - terminate connections */
 183                         struct smc_link_group *lgr;
 184
 185                         lgr = container_of(link, struct smc_link_group,
 186                                            lnk[SMC_SINGLE_LINK]);
 187                         smc_lgr_terminate(lgr);
 188                         return -EPIPE;
 189                 }
 190                 if (rc == -ERESTARTSYS)
 191                         return -EINTR;
 192                 if (idx == link->wr_tx_cnt)
 193                         return -EPIPE;
 194         }
 195         wr_id = smc_wr_tx_get_next_wr_id(link);
 196         wr_pend = &link->wr_tx_pends[idx];
 197         wr_pend->wr_id = wr_id;
 198         wr_pend->handler = handler;
 199         wr_pend->link = link;
 200         wr_pend->idx = idx;
 201         wr_ib = &link->wr_tx_ibs[idx];
 202         wr_ib->wr_id = wr_id;
 203         *wr_buf = &link->wr_tx_bufs[idx];
 204         *wr_pend_priv = &wr_pend->priv;
 205         return 0;
 206 }
 207
 208 int smc_wr_tx_put_slot(struct smc_link *link,
 209                        struct smc_wr_tx_pend_priv *wr_pend_priv)
 210 {
 211         struct smc_wr_tx_pend *pend;
 212
 213         pend = container_of(wr_pend_priv, struct smc_wr_tx_pend, priv);
 214         if (pend->idx < link->wr_tx_cnt) {
 215                 /* clear the full struct smc_wr_tx_pend including .priv */
 216                 memset(&link->wr_tx_pends[pend->idx], 0,
 217                        sizeof(link->wr_tx_pends[pend->idx]));
 218                 memset(&link->wr_tx_bufs[pend->idx], 0,
 219                        sizeof(link->wr_tx_bufs[pend->idx]));
 220                 test_and_clear_bit(pend->idx, link->wr_tx_mask);
 221                 return 1;
 222         }
 223
 224         return 0;
 225 }
 226
 227 /* Send prepared WR slot via ib_post_send.
 228  * @priv: pointer to smc_wr_tx_pend_priv identifying prepared message buffer
 229  */
 230 int smc_wr_tx_send(struct smc_link *link, struct smc_wr_tx_pend_priv *priv)
 231 {
 232         struct ib_send_wr *failed_wr = NULL;
 233         struct smc_wr_tx_pend *pend;
 234         int rc;
 235
 236         ib_req_notify_cq(link->smcibdev->roce_cq_send,
 237                          IB_CQ_SOLICITED_MASK | IB_CQ_REPORT_MISSED_EVENTS);
 238         pend = container_of(priv, struct smc_wr_tx_pend, priv);
 239         rc = ib_post_send(link->roce_qp, &link->wr_tx_ibs[pend->idx],
 240                           &failed_wr);
 241         if (rc)
 242                 smc_wr_tx_put_slot(link, priv);
 243         return rc;
 244 }
 245
 246 void smc_wr_tx_dismiss_slots(struct smc_link *link, u8 wr_rx_hdr_type,
 247                              smc_wr_tx_filter filter,
 248                              smc_wr_tx_dismisser dismisser,
 249                              unsigned long data)
 250 {
 251         struct smc_wr_tx_pend_priv *tx_pend;
 252         struct smc_wr_rx_hdr *wr_rx;
 253         int i;
 254
 255         for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
 256                 wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[i];
 257                 if (wr_rx->type != wr_rx_hdr_type)
 258                         continue;
 259                 tx_pend = &link->wr_tx_pends[i].priv;
 260                 if (filter(tx_pend, data))
 261                         dismisser(tx_pend);
 262         }
 263 }
 264
 265 bool smc_wr_tx_has_pending(struct smc_link *link, u8 wr_rx_hdr_type,
 266                            smc_wr_tx_filter filter, unsigned long data)
 267 {
 268         struct smc_wr_tx_pend_priv *tx_pend;
 269         struct smc_wr_rx_hdr *wr_rx;
 270         int i;
 271
 272         for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
 273                 wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[i];
 274                 if (wr_rx->type != wr_rx_hdr_type)
 275                         continue;
 276                 tx_pend = &link->wr_tx_pends[i].priv;
 277                 if (filter(tx_pend, data))
 278                         return true;
 279         }
 280         return false;
 281 }
 282
 283 /****************************** receive queue ********************************/
 284
 285 int smc_wr_rx_register_handler(struct smc_wr_rx_handler *handler)
 286 {
 287         struct smc_wr_rx_handler *h_iter;
 288         int rc = 0;
 289
 290         spin_lock(&smc_wr_rx_hash_lock);
 291         hash_for_each_possible(smc_wr_rx_hash, h_iter, list, handler->type) {
 292                 if (h_iter->type == handler->type) {
 293                         rc = -EEXIST;
 294                         goto out_unlock;
 295                 }
 296         }
 297         hash_add(smc_wr_rx_hash, &handler->list, handler->type);
 298 out_unlock:
 299         spin_unlock(&smc_wr_rx_hash_lock);
 300         return rc;
 301 }
 302
 303 /* Demultiplex a received work request based on the message type to its handler.
 304  * Relies on smc_wr_rx_hash having been completely filled before any IB WRs,
 305  * and not being modified any more afterwards so we don't need to lock it.
 306  */
 307 static inline void smc_wr_rx_demultiplex(struct ib_wc *wc)
 308 {
 309         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 310         struct smc_wr_rx_handler *handler;
 311         struct smc_wr_rx_hdr *wr_rx;
 312         u64 temp_wr_id;
 313         u32 index;
 314
 315         if (wc->byte_len < sizeof(*wr_rx))
 316                 return; /* short message */
 317         temp_wr_id = wc->wr_id;
 318         index = do_div(temp_wr_id, link->wr_rx_cnt);
 319         wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[index];
 320         hash_for_each_possible(smc_wr_rx_hash, handler, list, wr_rx->type) {
 321                 if (handler->type == wr_rx->type)
 322                         handler->handler(wc, wr_rx);
 323         }
 324 }
 325
 326 static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num)
 327 {
 328         struct smc_link *link;
 329         int i;
 330
 331         for (i = 0; i < num; i++) {
 332                 link = wc[i].qp->qp_context;
 333                 if (wc[i].status == IB_WC_SUCCESS) {
 334                         smc_wr_rx_demultiplex(&wc[i]);
 335                         smc_wr_rx_post(link); /* refill WR RX */
 336                 } else {
 337                         struct smc_link_group *lgr;
 338
 339                         /* handle status errors */
 340                         switch (wc[i].status) {
 341                         case IB_WC_RETRY_EXC_ERR:
 342                         case IB_WC_RNR_RETRY_EXC_ERR:
 343                         case IB_WC_WR_FLUSH_ERR:
 344                                 /* terminate connections of this link group
 345                                  * abnormally
 346                                  */
 347                                 lgr = container_of(link, struct smc_link_group,
 348                                                    lnk[SMC_SINGLE_LINK]);
 349                                 smc_lgr_terminate(lgr);
 350                                 break;
 351                         default:
 352                                 smc_wr_rx_post(link); /* refill WR RX */
 353                                 break;
 354                         }
 355                 }
 356         }
 357 }
 358
 359 static void smc_wr_rx_tasklet_fn(unsigned long data)
 360 {
 361         struct smc_ib_device *dev = (struct smc_ib_device *)data;
 362         struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
 363         int polled = 0;
 364         int rc;
 365
 366 again:
 367         polled++;
 368         do {
 369                 memset(&wc, 0, sizeof(wc));
 370                 rc = ib_poll_cq(dev->roce_cq_recv, SMC_WR_MAX_POLL_CQE, wc);
 371                 if (polled == 1) {
 372                         ib_req_notify_cq(dev->roce_cq_recv,
 373                                          IB_CQ_SOLICITED_MASK
 374                                          | IB_CQ_REPORT_MISSED_EVENTS);
 375                 }
 376                 if (!rc)
 377                         break;
 378                 smc_wr_rx_process_cqes(&wc[0], rc);
 379         } while (rc > 0);
 380         if (polled == 1)
 381                 goto again;
 382 }
 383
 384 void smc_wr_rx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
 385 {
 386         struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
 387
 388         tasklet_schedule(&dev->recv_tasklet);
 389 }
 390
 391 int smc_wr_rx_post_init(struct smc_link *link)
 392 {
 393         u32 i;
 394         int rc = 0;
 395
 396         for (i = 0; i < link->wr_rx_cnt; i++)
 397                 rc = smc_wr_rx_post(link);
 398         return rc;
 399 }
 400
 401 /***************************** init, exit, misc ******************************/
 402
 403 void smc_wr_remember_qp_attr(struct smc_link *lnk)
 404 {
 405         struct ib_qp_attr *attr = &lnk->qp_attr;
 406         struct ib_qp_init_attr init_attr;
 407
 408         memset(attr, 0, sizeof(*attr));
 409         memset(&init_attr, 0, sizeof(init_attr));
 410         ib_query_qp(lnk->roce_qp, attr,
 411                     IB_QP_STATE |
 412                     IB_QP_CUR_STATE |
 413                     IB_QP_PKEY_INDEX |
 414                     IB_QP_PORT |
 415                     IB_QP_QKEY |
 416                     IB_QP_AV |
 417                     IB_QP_PATH_MTU |
 418                     IB_QP_TIMEOUT |
 419                     IB_QP_RETRY_CNT |
 420                     IB_QP_RNR_RETRY |
 421                     IB_QP_RQ_PSN |
 422                     IB_QP_ALT_PATH |
 423                     IB_QP_MIN_RNR_TIMER |
 424                     IB_QP_SQ_PSN |
 425                     IB_QP_PATH_MIG_STATE |
 426                     IB_QP_CAP |
 427                     IB_QP_DEST_QPN,
 428                     &init_attr);
 429
 430         lnk->wr_tx_cnt = min_t(size_t, SMC_WR_BUF_CNT,
 431                                lnk->qp_attr.cap.max_send_wr);
 432         lnk->wr_rx_cnt = min_t(size_t, SMC_WR_BUF_CNT * 3,
 433                                lnk->qp_attr.cap.max_recv_wr);
 434 }
 435
 436 static void smc_wr_init_sge(struct smc_link *lnk)
 437 {
 438         u32 i;
 439
 440         for (i = 0; i < lnk->wr_tx_cnt; i++) {
 441                 lnk->wr_tx_sges[i].addr =
 442                         lnk->wr_tx_dma_addr + i * SMC_WR_BUF_SIZE;
 443                 lnk->wr_tx_sges[i].length = SMC_WR_TX_SIZE;
 444                 lnk->wr_tx_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
 445                 lnk->wr_tx_ibs[i].next = NULL;
 446                 lnk->wr_tx_ibs[i].sg_list = &lnk->wr_tx_sges[i];
 447                 lnk->wr_tx_ibs[i].num_sge = 1;
 448                 lnk->wr_tx_ibs[i].opcode = IB_WR_SEND;
 449                 lnk->wr_tx_ibs[i].send_flags =
 450                         IB_SEND_SIGNALED | IB_SEND_SOLICITED | IB_SEND_INLINE;
 451         }
 452         for (i = 0; i < lnk->wr_rx_cnt; i++) {
 453                 lnk->wr_rx_sges[i].addr =
 454                         lnk->wr_rx_dma_addr + i * SMC_WR_BUF_SIZE;
 455                 lnk->wr_rx_sges[i].length = SMC_WR_BUF_SIZE;
 456                 lnk->wr_rx_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
 457                 lnk->wr_rx_ibs[i].next = NULL;
 458                 lnk->wr_rx_ibs[i].sg_list = &lnk->wr_rx_sges[i];
 459                 lnk->wr_rx_ibs[i].num_sge = 1;
 460         }
 461 }
 462
 463 void smc_wr_free_link(struct smc_link *lnk)
 464 {
 465         struct ib_device *ibdev;
 466
 467         memset(lnk->wr_tx_mask, 0,
 468                BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
 469
 470         if (!lnk->smcibdev)
 471                 return;
 472         ibdev = lnk->smcibdev->ibdev;
 473
 474         if (lnk->wr_rx_dma_addr) {
 475                 ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
 476                                     SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
 477                                     DMA_FROM_DEVICE);
 478                 lnk->wr_rx_dma_addr = 0;
 479         }
 480         if (lnk->wr_tx_dma_addr) {
 481                 ib_dma_unmap_single(ibdev, lnk->wr_tx_dma_addr,
 482                                     SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
 483                                     DMA_TO_DEVICE);
 484                 lnk->wr_tx_dma_addr = 0;
 485         }
 486 }
 487
 488 void smc_wr_free_link_mem(struct smc_link *lnk)
 489 {
 490         kfree(lnk->wr_tx_pends);
 491         lnk->wr_tx_pends = NULL;
 492         kfree(lnk->wr_tx_mask);
 493         lnk->wr_tx_mask = NULL;
 494         kfree(lnk->wr_tx_sges);
 495         lnk->wr_tx_sges = NULL;
 496         kfree(lnk->wr_rx_sges);
 497         lnk->wr_rx_sges = NULL;
 498         kfree(lnk->wr_rx_ibs);
 499         lnk->wr_rx_ibs = NULL;
 500         kfree(lnk->wr_tx_ibs);
 501         lnk->wr_tx_ibs = NULL;
 502         kfree(lnk->wr_tx_bufs);
 503         lnk->wr_tx_bufs = NULL;
 504         kfree(lnk->wr_rx_bufs);
 505         lnk->wr_rx_bufs = NULL;
 506 }
 507
 508 int smc_wr_alloc_link_mem(struct smc_link *link)
 509 {
 510         /* allocate link related memory */
 511         link->wr_tx_bufs = kcalloc(SMC_WR_BUF_CNT, SMC_WR_BUF_SIZE, GFP_KERNEL);
 512         if (!link->wr_tx_bufs)
 513                 goto no_mem;
 514         link->wr_rx_bufs = kcalloc(SMC_WR_BUF_CNT * 3, SMC_WR_BUF_SIZE,
 515                                    GFP_KERNEL);
 516         if (!link->wr_rx_bufs)
 517                 goto no_mem_wr_tx_bufs;
 518         link->wr_tx_ibs = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_ibs[0]),
 519                                   GFP_KERNEL);
 520         if (!link->wr_tx_ibs)
 521                 goto no_mem_wr_rx_bufs;
 522         link->wr_rx_ibs = kcalloc(SMC_WR_BUF_CNT * 3,
 523                                   sizeof(link->wr_rx_ibs[0]),
 524                                   GFP_KERNEL);
 525         if (!link->wr_rx_ibs)
 526                 goto no_mem_wr_tx_ibs;
 527         link->wr_tx_sges = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_sges[0]),
 528                                    GFP_KERNEL);
 529         if (!link->wr_tx_sges)
 530                 goto no_mem_wr_rx_ibs;
 531         link->wr_rx_sges = kcalloc(SMC_WR_BUF_CNT * 3,
 532                                    sizeof(link->wr_rx_sges[0]),
 533                                    GFP_KERNEL);
 534         if (!link->wr_rx_sges)
 535                 goto no_mem_wr_tx_sges;
 536         link->wr_tx_mask = kzalloc(
 537                 BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*link->wr_tx_mask),
 538                 GFP_KERNEL);
 539         if (!link->wr_tx_mask)
 540                 goto no_mem_wr_rx_sges;
 541         link->wr_tx_pends = kcalloc(SMC_WR_BUF_CNT,
 542                                     sizeof(link->wr_tx_pends[0]),
 543                                     GFP_KERNEL);
 544         if (!link->wr_tx_pends)
 545                 goto no_mem_wr_tx_mask;
 546         return 0;
 547
 548 no_mem_wr_tx_mask:
 549         kfree(link->wr_tx_mask);
 550 no_mem_wr_rx_sges:
 551         kfree(link->wr_rx_sges);
 552 no_mem_wr_tx_sges:
 553         kfree(link->wr_tx_sges);
 554 no_mem_wr_rx_ibs:
 555         kfree(link->wr_rx_ibs);
 556 no_mem_wr_tx_ibs:
 557         kfree(link->wr_tx_ibs);
 558 no_mem_wr_rx_bufs:
 559         kfree(link->wr_rx_bufs);
 560 no_mem_wr_tx_bufs:
 561         kfree(link->wr_tx_bufs);
 562 no_mem:
 563         return -ENOMEM;
 564 }
 565
 566 void smc_wr_remove_dev(struct smc_ib_device *smcibdev)
 567 {
 568         tasklet_kill(&smcibdev->recv_tasklet);
 569         tasklet_kill(&smcibdev->send_tasklet);
 570 }
 571
 572 void smc_wr_add_dev(struct smc_ib_device *smcibdev)
 573 {
 574         tasklet_init(&smcibdev->recv_tasklet, smc_wr_rx_tasklet_fn,
 575                      (unsigned long)smcibdev);
 576         tasklet_init(&smcibdev->send_tasklet, smc_wr_tx_tasklet_fn,
 577                      (unsigned long)smcibdev);
 578 }
 579
 580 int smc_wr_create_link(struct smc_link *lnk)
 581 {
 582         struct ib_device *ibdev = lnk->smcibdev->ibdev;
 583         int rc = 0;
 584
 585         smc_wr_tx_set_wr_id(&lnk->wr_tx_id, 0);
 586         lnk->wr_rx_id = 0;
 587         lnk->wr_rx_dma_addr = ib_dma_map_single(
 588                 ibdev, lnk->wr_rx_bufs, SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
 589                 DMA_FROM_DEVICE);
 590         if (ib_dma_mapping_error(ibdev, lnk->wr_rx_dma_addr)) {
 591                 lnk->wr_rx_dma_addr = 0;
 592                 rc = -EIO;
 593                 goto out;
 594         }
 595         lnk->wr_tx_dma_addr = ib_dma_map_single(
 596                 ibdev, lnk->wr_tx_bufs, SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
 597                 DMA_TO_DEVICE);
 598         if (ib_dma_mapping_error(ibdev, lnk->wr_tx_dma_addr)) {
 599                 rc = -EIO;
 600                 goto dma_unmap;
 601         }
 602         smc_wr_init_sge(lnk);
 603         memset(lnk->wr_tx_mask, 0,
 604                BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
 605         return rc;
 606
 607 dma_unmap:
 608         ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
 609                             SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
 610                             DMA_FROM_DEVICE);
 611         lnk->wr_rx_dma_addr = 0;
 612 out:
 613         return rc;
 614 }