net/smc/smc_core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Shared Memory Communications over RDMA (SMC-R) and RoCE
   4  *
   5  *  Basic Transport Functions exploiting Infiniband API
   6  *
   7  *  Copyright IBM Corp. 2016
   8  *
   9  *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
  10  */
  11
  12 #include <linux/socket.h>
  13 #include <linux/if_vlan.h>
  14 #include <linux/random.h>
  15 #include <linux/workqueue.h>
  16 #include <net/tcp.h>
  17 #include <net/sock.h>
  18 #include <rdma/ib_verbs.h>
  19
  20 #include "smc.h"
  21 #include "smc_clc.h"
  22 #include "smc_core.h"
  23 #include "smc_ib.h"
  24 #include "smc_wr.h"
  25 #include "smc_llc.h"
  26 #include "smc_cdc.h"
  27 #include "smc_close.h"
  28
  29 #define SMC_LGR_NUM_INCR                256
  30 #define SMC_LGR_FREE_DELAY_SERV         (600 * HZ)
  31 #define SMC_LGR_FREE_DELAY_CLNT         (SMC_LGR_FREE_DELAY_SERV + 10)
  32
  33 static u32 smc_lgr_num;                 /* unique link group number */
  34
  35 /* Register connection's alert token in our lookup structure.
  36  * To use rbtrees we have to implement our own insert core.
  37  * Requires @conns_lock
  38  * @smc         connection to register
  39  * Returns 0 on success, != otherwise.
  40  */
  41 static void smc_lgr_add_alert_token(struct smc_connection *conn)
  42 {
  43         struct rb_node **link, *parent = NULL;
  44         u32 token = conn->alert_token_local;
  45
  46         link = &conn->lgr->conns_all.rb_node;
  47         while (*link) {
  48                 struct smc_connection *cur = rb_entry(*link,
  49                                         struct smc_connection, alert_node);
  50
  51                 parent = *link;
  52                 if (cur->alert_token_local > token)
  53                         link = &parent->rb_left;
  54                 else
  55                         link = &parent->rb_right;
  56         }
  57         /* Put the new node there */
  58         rb_link_node(&conn->alert_node, parent, link);
  59         rb_insert_color(&conn->alert_node, &conn->lgr->conns_all);
  60 }
  61
  62 /* Register connection in link group by assigning an alert token
  63  * registered in a search tree.
  64  * Requires @conns_lock
  65  * Note that '0' is a reserved value and not assigned.
  66  */
  67 static void smc_lgr_register_conn(struct smc_connection *conn)
  68 {
  69         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
  70         static atomic_t nexttoken = ATOMIC_INIT(0);
  71
  72         /* find a new alert_token_local value not yet used by some connection
  73          * in this link group
  74          */
  75         sock_hold(&smc->sk); /* sock_put in smc_lgr_unregister_conn() */
  76         while (!conn->alert_token_local) {
  77                 conn->alert_token_local = atomic_inc_return(&nexttoken);
  78                 if (smc_lgr_find_conn(conn->alert_token_local, conn->lgr))
  79                         conn->alert_token_local = 0;
  80         }
  81         smc_lgr_add_alert_token(conn);
  82         conn->lgr->conns_num++;
  83 }
  84
  85 /* Unregister connection and reset the alert token of the given connection<
  86  */
  87 static void __smc_lgr_unregister_conn(struct smc_connection *conn)
  88 {
  89         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
  90         struct smc_link_group *lgr = conn->lgr;
  91
  92         rb_erase(&conn->alert_node, &lgr->conns_all);
  93         lgr->conns_num--;
  94         conn->alert_token_local = 0;
  95         conn->lgr = NULL;
  96         sock_put(&smc->sk); /* sock_hold in smc_lgr_register_conn() */
  97 }
  98
  99 /* Unregister connection and trigger lgr freeing if applicable
 100  */
 101 static void smc_lgr_unregister_conn(struct smc_connection *conn)
 102 {
 103         struct smc_link_group *lgr = conn->lgr;
 104         int reduced = 0;
 105
 106         if (!lgr)
 107                 return;
 108         write_lock_bh(&lgr->conns_lock);
 109         if (conn->alert_token_local) {
 110                 reduced = 1;
 111                 __smc_lgr_unregister_conn(conn);
 112         }
 113         write_unlock_bh(&lgr->conns_lock);
 114         if (!reduced || lgr->conns_num)
 115                 return;
 116         /* client link group creation always follows the server link group
 117          * creation. For client use a somewhat higher removal delay time,
 118          * otherwise there is a risk of out-of-sync link groups.
 119          */
 120         mod_delayed_work(system_wq, &lgr->free_work,
 121                          lgr->role == SMC_CLNT ? SMC_LGR_FREE_DELAY_CLNT :
 122                                                  SMC_LGR_FREE_DELAY_SERV);
 123 }
 124
 125 static void smc_lgr_free_work(struct work_struct *work)
 126 {
 127         struct smc_link_group *lgr = container_of(to_delayed_work(work),
 128                                                   struct smc_link_group,
 129                                                   free_work);
 130         bool conns;
 131
 132         spin_lock_bh(&smc_lgr_list.lock);
 133         read_lock_bh(&lgr->conns_lock);
 134         conns = RB_EMPTY_ROOT(&lgr->conns_all);
 135         read_unlock_bh(&lgr->conns_lock);
 136         if (!conns) { /* number of lgr connections is no longer zero */
 137                 spin_unlock_bh(&smc_lgr_list.lock);
 138                 return;
 139         }
 140         list_del_init(&lgr->list); /* remove from smc_lgr_list */
 141         spin_unlock_bh(&smc_lgr_list.lock);
 142         smc_lgr_free(lgr);
 143 }
 144
 145 /* create a new SMC link group */
 146 static int smc_lgr_create(struct smc_sock *smc, __be32 peer_in_addr,
 147                           struct smc_ib_device *smcibdev, u8 ibport,
 148                           char *peer_systemid, unsigned short vlan_id)
 149 {
 150         struct smc_link_group *lgr;
 151         struct smc_link *lnk;
 152         u8 rndvec[3];
 153         int rc = 0;
 154         int i;
 155
 156         lgr = kzalloc(sizeof(*lgr), GFP_KERNEL);
 157         if (!lgr) {
 158                 rc = -ENOMEM;
 159                 goto out;
 160         }
 161         lgr->role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
 162         lgr->sync_err = false;
 163         lgr->daddr = peer_in_addr;
 164         memcpy(lgr->peer_systemid, peer_systemid, SMC_SYSTEMID_LEN);
 165         lgr->vlan_id = vlan_id;
 166         rwlock_init(&lgr->sndbufs_lock);
 167         rwlock_init(&lgr->rmbs_lock);
 168         for (i = 0; i < SMC_RMBE_SIZES; i++) {
 169                 INIT_LIST_HEAD(&lgr->sndbufs[i]);
 170                 INIT_LIST_HEAD(&lgr->rmbs[i]);
 171         }
 172         smc_lgr_num += SMC_LGR_NUM_INCR;
 173         memcpy(&lgr->id, (u8 *)&smc_lgr_num, SMC_LGR_ID_SIZE);
 174         INIT_DELAYED_WORK(&lgr->free_work, smc_lgr_free_work);
 175         lgr->conns_all = RB_ROOT;
 176
 177         lnk = &lgr->lnk[SMC_SINGLE_LINK];
 178         /* initialize link */
 179         lnk->link_id = SMC_SINGLE_LINK;
 180         lnk->smcibdev = smcibdev;
 181         lnk->ibport = ibport;
 182         lnk->path_mtu = smcibdev->pattr[ibport - 1].active_mtu;
 183         if (!smcibdev->initialized)
 184                 smc_ib_setup_per_ibdev(smcibdev);
 185         get_random_bytes(rndvec, sizeof(rndvec));
 186         lnk->psn_initial = rndvec[0] + (rndvec[1] << 8) + (rndvec[2] << 16);
 187         rc = smc_wr_alloc_link_mem(lnk);
 188         if (rc)
 189                 goto free_lgr;
 190         rc = smc_ib_create_protection_domain(lnk);
 191         if (rc)
 192                 goto free_link_mem;
 193         rc = smc_ib_create_queue_pair(lnk);
 194         if (rc)
 195                 goto dealloc_pd;
 196         rc = smc_wr_create_link(lnk);
 197         if (rc)
 198                 goto destroy_qp;
 199         init_completion(&lnk->llc_confirm);
 200         init_completion(&lnk->llc_confirm_resp);
 201
 202         smc->conn.lgr = lgr;
 203         rwlock_init(&lgr->conns_lock);
 204         spin_lock_bh(&smc_lgr_list.lock);
 205         list_add(&lgr->list, &smc_lgr_list.list);
 206         spin_unlock_bh(&smc_lgr_list.lock);
 207         return 0;
 208
 209 destroy_qp:
 210         smc_ib_destroy_queue_pair(lnk);
 211 dealloc_pd:
 212         smc_ib_dealloc_protection_domain(lnk);
 213 free_link_mem:
 214         smc_wr_free_link_mem(lnk);
 215 free_lgr:
 216         kfree(lgr);
 217 out:
 218         return rc;
 219 }
 220
 221 static void smc_buf_unuse(struct smc_connection *conn)
 222 {
 223         if (conn->sndbuf_desc) {
 224                 conn->sndbuf_desc->used = 0;
 225                 conn->sndbuf_size = 0;
 226         }
 227         if (conn->rmb_desc) {
 228                 conn->rmb_desc->reused = true;
 229                 conn->rmb_desc->used = 0;
 230                 conn->rmbe_size = 0;
 231         }
 232 }
 233
 234 /* remove a finished connection from its link group */
 235 void smc_conn_free(struct smc_connection *conn)
 236 {
 237         struct smc_link_group *lgr = conn->lgr;
 238
 239         if (!lgr)
 240                 return;
 241         smc_cdc_tx_dismiss_slots(conn);
 242         smc_lgr_unregister_conn(conn);
 243         smc_buf_unuse(conn);
 244 }
 245
 246 static void smc_link_clear(struct smc_link *lnk)
 247 {
 248         lnk->peer_qpn = 0;
 249         smc_ib_modify_qp_reset(lnk);
 250         smc_wr_free_link(lnk);
 251         smc_ib_destroy_queue_pair(lnk);
 252         smc_ib_dealloc_protection_domain(lnk);
 253         smc_wr_free_link_mem(lnk);
 254 }
 255
 256 static void smc_buf_free(struct smc_buf_desc *buf_desc, struct smc_link *lnk,
 257                          bool is_rmb)
 258 {
 259         if (is_rmb) {
 260                 if (buf_desc->mr_rx[SMC_SINGLE_LINK])
 261                         smc_ib_put_memory_region(
 262                                         buf_desc->mr_rx[SMC_SINGLE_LINK]);
 263                 smc_ib_buf_unmap_sg(lnk->smcibdev, buf_desc,
 264                                     DMA_FROM_DEVICE);
 265         } else {
 266                 smc_ib_buf_unmap_sg(lnk->smcibdev, buf_desc,
 267                                     DMA_TO_DEVICE);
 268         }
 269         sg_free_table(&buf_desc->sgt[SMC_SINGLE_LINK]);
 270         if (buf_desc->cpu_addr)
 271                 free_pages((unsigned long)buf_desc->cpu_addr, buf_desc->order);
 272         kfree(buf_desc);
 273 }
 274
 275 static void __smc_lgr_free_bufs(struct smc_link_group *lgr, bool is_rmb)
 276 {
 277         struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK];
 278         struct smc_buf_desc *buf_desc, *bf_desc;
 279         struct list_head *buf_list;
 280         int i;
 281
 282         for (i = 0; i < SMC_RMBE_SIZES; i++) {
 283                 if (is_rmb)
 284                         buf_list = &lgr->rmbs[i];
 285                 else
 286                         buf_list = &lgr->sndbufs[i];
 287                 list_for_each_entry_safe(buf_desc, bf_desc, buf_list,
 288                                          list) {
 289                         list_del(&buf_desc->list);
 290                         smc_buf_free(buf_desc, lnk, is_rmb);
 291                 }
 292         }
 293 }
 294
 295 static void smc_lgr_free_bufs(struct smc_link_group *lgr)
 296 {
 297         /* free send buffers */
 298         __smc_lgr_free_bufs(lgr, false);
 299         /* free rmbs */
 300         __smc_lgr_free_bufs(lgr, true);
 301 }
 302
 303 /* remove a link group */
 304 void smc_lgr_free(struct smc_link_group *lgr)
 305 {
 306         smc_lgr_free_bufs(lgr);
 307         smc_link_clear(&lgr->lnk[SMC_SINGLE_LINK]);
 308         kfree(lgr);
 309 }
 310
 311 /* terminate linkgroup abnormally */
 312 void smc_lgr_terminate(struct smc_link_group *lgr)
 313 {
 314         struct smc_connection *conn;
 315         struct smc_sock *smc;
 316         struct rb_node *node;
 317
 318         spin_lock_bh(&smc_lgr_list.lock);
 319         if (list_empty(&lgr->list)) {
 320                 /* termination already triggered */
 321                 spin_unlock_bh(&smc_lgr_list.lock);
 322                 return;
 323         }
 324         /* do not use this link group for new connections */
 325         list_del_init(&lgr->list);
 326         spin_unlock_bh(&smc_lgr_list.lock);
 327
 328         write_lock_bh(&lgr->conns_lock);
 329         node = rb_first(&lgr->conns_all);
 330         while (node) {
 331                 conn = rb_entry(node, struct smc_connection, alert_node);
 332                 smc = container_of(conn, struct smc_sock, conn);
 333                 sock_hold(&smc->sk);
 334                 __smc_lgr_unregister_conn(conn);
 335                 schedule_work(&conn->close_work);
 336                 sock_put(&smc->sk);
 337                 node = rb_first(&lgr->conns_all);
 338         }
 339         write_unlock_bh(&lgr->conns_lock);
 340 }
 341
 342 /* Determine vlan of internal TCP socket.
 343  * @vlan_id: address to store the determined vlan id into
 344  */
 345 static int smc_vlan_by_tcpsk(struct socket *clcsock, unsigned short *vlan_id)
 346 {
 347         struct dst_entry *dst = sk_dst_get(clcsock->sk);
 348         int rc = 0;
 349
 350         *vlan_id = 0;
 351         if (!dst) {
 352                 rc = -ENOTCONN;
 353                 goto out;
 354         }
 355         if (!dst->dev) {
 356                 rc = -ENODEV;
 357                 goto out_rel;
 358         }
 359
 360         if (is_vlan_dev(dst->dev))
 361                 *vlan_id = vlan_dev_vlan_id(dst->dev);
 362
 363 out_rel:
 364         dst_release(dst);
 365 out:
 366         return rc;
 367 }
 368
 369 /* determine the link gid matching the vlan id of the link group */
 370 static int smc_link_determine_gid(struct smc_link_group *lgr)
 371 {
 372         struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK];
 373         struct ib_gid_attr gattr;
 374         union ib_gid gid;
 375         int i;
 376
 377         if (!lgr->vlan_id) {
 378                 lnk->gid = lnk->smcibdev->gid[lnk->ibport - 1];
 379                 return 0;
 380         }
 381
 382         for (i = 0; i < lnk->smcibdev->pattr[lnk->ibport - 1].gid_tbl_len;
 383              i++) {
 384                 if (ib_query_gid(lnk->smcibdev->ibdev, lnk->ibport, i, &gid,
 385                                  &gattr))
 386                         continue;
 387                 if (gattr.ndev &&
 388                     (vlan_dev_vlan_id(gattr.ndev) == lgr->vlan_id)) {
 389                         lnk->gid = gid;
 390                         return 0;
 391                 }
 392         }
 393         return -ENODEV;
 394 }
 395
 396 /* create a new SMC connection (and a new link group if necessary) */
 397 int smc_conn_create(struct smc_sock *smc, __be32 peer_in_addr,
 398                     struct smc_ib_device *smcibdev, u8 ibport,
 399                     struct smc_clc_msg_local *lcl, int srv_first_contact)
 400 {
 401         struct smc_connection *conn = &smc->conn;
 402         struct smc_link_group *lgr;
 403         unsigned short vlan_id;
 404         enum smc_lgr_role role;
 405         int local_contact = SMC_FIRST_CONTACT;
 406         int rc = 0;
 407
 408         role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
 409         rc = smc_vlan_by_tcpsk(smc->clcsock, &vlan_id);
 410         if (rc)
 411                 return rc;
 412
 413         if ((role == SMC_CLNT) && srv_first_contact)
 414                 /* create new link group as well */
 415                 goto create;
 416
 417         /* determine if an existing link group can be reused */
 418         spin_lock_bh(&smc_lgr_list.lock);
 419         list_for_each_entry(lgr, &smc_lgr_list.list, list) {
 420                 write_lock_bh(&lgr->conns_lock);
 421                 if (!memcmp(lgr->peer_systemid, lcl->id_for_peer,
 422                             SMC_SYSTEMID_LEN) &&
 423                     !memcmp(lgr->lnk[SMC_SINGLE_LINK].peer_gid, &lcl->gid,
 424                             SMC_GID_SIZE) &&
 425                     !memcmp(lgr->lnk[SMC_SINGLE_LINK].peer_mac, lcl->mac,
 426                             sizeof(lcl->mac)) &&
 427                     !lgr->sync_err &&
 428                     (lgr->role == role) &&
 429                     (lgr->vlan_id == vlan_id) &&
 430                     ((role == SMC_CLNT) ||
 431                      (lgr->conns_num < SMC_RMBS_PER_LGR_MAX))) {
 432                         /* link group found */
 433                         local_contact = SMC_REUSE_CONTACT;
 434                         conn->lgr = lgr;
 435                         smc_lgr_register_conn(conn); /* add smc conn to lgr */
 436                         if (delayed_work_pending(&lgr->free_work))
 437                                 cancel_delayed_work(&lgr->free_work);
 438                         write_unlock_bh(&lgr->conns_lock);
 439                         break;
 440                 }
 441                 write_unlock_bh(&lgr->conns_lock);
 442         }
 443         spin_unlock_bh(&smc_lgr_list.lock);
 444
 445         if (role == SMC_CLNT && !srv_first_contact &&
 446             (local_contact == SMC_FIRST_CONTACT)) {
 447                 /* Server reuses a link group, but Client wants to start
 448                  * a new one
 449                  * send out_of_sync decline, reason synchr. error
 450                  */
 451                 return -ENOLINK;
 452         }
 453
 454 create:
 455         if (local_contact == SMC_FIRST_CONTACT) {
 456                 rc = smc_lgr_create(smc, peer_in_addr, smcibdev, ibport,
 457                                     lcl->id_for_peer, vlan_id);
 458                 if (rc)
 459                         goto out;
 460                 smc_lgr_register_conn(conn); /* add smc conn to lgr */
 461                 rc = smc_link_determine_gid(conn->lgr);
 462         }
 463         conn->local_tx_ctrl.common.type = SMC_CDC_MSG_TYPE;
 464         conn->local_tx_ctrl.len = sizeof(struct smc_cdc_msg);
 465 #ifndef KERNEL_HAS_ATOMIC64
 466         spin_lock_init(&conn->acurs_lock);
 467 #endif
 468
 469 out:
 470         return rc ? rc : local_contact;
 471 }
 472
 473 /* try to reuse a sndbuf or rmb description slot for a certain
 474  * buffer size; if not available, return NULL
 475  */
 476 static inline
 477 struct smc_buf_desc *smc_buf_get_slot(struct smc_link_group *lgr,
 478                                       int compressed_bufsize,
 479                                       rwlock_t *lock,
 480                                       struct list_head *buf_list)
 481 {
 482         struct smc_buf_desc *buf_slot;
 483
 484         read_lock_bh(lock);
 485         list_for_each_entry(buf_slot, buf_list, list) {
 486                 if (cmpxchg(&buf_slot->used, 0, 1) == 0) {
 487                         read_unlock_bh(lock);
 488                         return buf_slot;
 489                 }
 490         }
 491         read_unlock_bh(lock);
 492         return NULL;
 493 }
 494
 495 /* one of the conditions for announcing a receiver's current window size is
 496  * that it "results in a minimum increase in the window size of 10% of the
 497  * receive buffer space" [RFC7609]
 498  */
 499 static inline int smc_rmb_wnd_update_limit(int rmbe_size)
 500 {
 501         return min_t(int, rmbe_size / 10, SOCK_MIN_SNDBUF / 2);
 502 }
 503
 504 static struct smc_buf_desc *smc_new_buf_create(struct smc_link_group *lgr,
 505                                                bool is_rmb, int bufsize)
 506 {
 507         struct smc_buf_desc *buf_desc;
 508         struct smc_link *lnk;
 509         int rc;
 510
 511         /* try to alloc a new buffer */
 512         buf_desc = kzalloc(sizeof(*buf_desc), GFP_KERNEL);
 513         if (!buf_desc)
 514                 return ERR_PTR(-ENOMEM);
 515
 516         buf_desc->cpu_addr =
 517                 (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN |
 518                                          __GFP_NOMEMALLOC |
 519                                          __GFP_NORETRY | __GFP_ZERO,
 520                                          get_order(bufsize));
 521         if (!buf_desc->cpu_addr) {
 522                 kfree(buf_desc);
 523                 return ERR_PTR(-EAGAIN);
 524         }
 525         buf_desc->order = get_order(bufsize);
 526
 527         /* build the sg table from the pages */
 528         lnk = &lgr->lnk[SMC_SINGLE_LINK];
 529         rc = sg_alloc_table(&buf_desc->sgt[SMC_SINGLE_LINK], 1,
 530                             GFP_KERNEL);
 531         if (rc) {
 532                 smc_buf_free(buf_desc, lnk, is_rmb);
 533                 return ERR_PTR(rc);
 534         }
 535         sg_set_buf(buf_desc->sgt[SMC_SINGLE_LINK].sgl,
 536                    buf_desc->cpu_addr, bufsize);
 537
 538         /* map sg table to DMA address */
 539         rc = smc_ib_buf_map_sg(lnk->smcibdev, buf_desc,
 540                                is_rmb ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
 541         /* SMC protocol depends on mapping to one DMA address only */
 542         if (rc != 1)  {
 543                 smc_buf_free(buf_desc, lnk, is_rmb);
 544                 return ERR_PTR(-EAGAIN);
 545         }
 546
 547         /* create a new memory region for the RMB */
 548         if (is_rmb) {
 549                 rc = smc_ib_get_memory_region(lnk->roce_pd,
 550                                               IB_ACCESS_REMOTE_WRITE |
 551                                               IB_ACCESS_LOCAL_WRITE,
 552                                               buf_desc);
 553                 if (rc) {
 554                         smc_buf_free(buf_desc, lnk, is_rmb);
 555                         return ERR_PTR(rc);
 556                 }
 557         }
 558
 559         return buf_desc;
 560 }
 561
 562 static int __smc_buf_create(struct smc_sock *smc, bool is_rmb)
 563 {
 564         struct smc_connection *conn = &smc->conn;
 565         struct smc_link_group *lgr = conn->lgr;
 566         struct smc_buf_desc *buf_desc = NULL;
 567         struct list_head *buf_list;
 568         int bufsize, bufsize_short;
 569         int sk_buf_size;
 570         rwlock_t *lock;
 571
 572         if (is_rmb)
 573                 /* use socket recv buffer size (w/o overhead) as start value */
 574                 sk_buf_size = smc->sk.sk_rcvbuf / 2;
 575         else
 576                 /* use socket send buffer size (w/o overhead) as start value */
 577                 sk_buf_size = smc->sk.sk_sndbuf / 2;
 578
 579         for (bufsize_short = smc_compress_bufsize(sk_buf_size);
 580              bufsize_short >= 0; bufsize_short--) {
 581
 582                 if (is_rmb) {
 583                         lock = &lgr->rmbs_lock;
 584                         buf_list = &lgr->rmbs[bufsize_short];
 585                 } else {
 586                         lock = &lgr->sndbufs_lock;
 587                         buf_list = &lgr->sndbufs[bufsize_short];
 588                 }
 589                 bufsize = smc_uncompress_bufsize(bufsize_short);
 590                 if ((1 << get_order(bufsize)) > SG_MAX_SINGLE_ALLOC)
 591                         continue;
 592
 593                 /* check for reusable slot in the link group */
 594                 buf_desc = smc_buf_get_slot(lgr, bufsize_short, lock, buf_list);
 595                 if (buf_desc) {
 596                         memset(buf_desc->cpu_addr, 0, bufsize);
 597                         break; /* found reusable slot */
 598                 }
 599
 600                 buf_desc = smc_new_buf_create(lgr, is_rmb, bufsize);
 601                 if (PTR_ERR(buf_desc) == -ENOMEM)
 602                         break;
 603                 if (IS_ERR(buf_desc))
 604                         continue;
 605
 606                 buf_desc->used = 1;
 607                 write_lock_bh(lock);
 608                 list_add(&buf_desc->list, buf_list);
 609                 write_unlock_bh(lock);
 610                 break; /* found */
 611         }
 612
 613         if (IS_ERR(buf_desc))
 614                 return -ENOMEM;
 615
 616         if (is_rmb) {
 617                 conn->rmb_desc = buf_desc;
 618                 conn->rmbe_size = bufsize;
 619                 conn->rmbe_size_short = bufsize_short;
 620                 smc->sk.sk_rcvbuf = bufsize * 2;
 621                 atomic_set(&conn->bytes_to_rcv, 0);
 622                 conn->rmbe_update_limit = smc_rmb_wnd_update_limit(bufsize);
 623         } else {
 624                 conn->sndbuf_desc = buf_desc;
 625                 conn->sndbuf_size = bufsize;
 626                 smc->sk.sk_sndbuf = bufsize * 2;
 627                 atomic_set(&conn->sndbuf_space, bufsize);
 628         }
 629         return 0;
 630 }
 631
 632 void smc_sndbuf_sync_sg_for_cpu(struct smc_connection *conn)
 633 {
 634         struct smc_link_group *lgr = conn->lgr;
 635
 636         smc_ib_sync_sg_for_cpu(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
 637                                conn->sndbuf_desc, DMA_TO_DEVICE);
 638 }
 639
 640 void smc_sndbuf_sync_sg_for_device(struct smc_connection *conn)
 641 {
 642         struct smc_link_group *lgr = conn->lgr;
 643
 644         smc_ib_sync_sg_for_device(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
 645                                   conn->sndbuf_desc, DMA_TO_DEVICE);
 646 }
 647
 648 void smc_rmb_sync_sg_for_cpu(struct smc_connection *conn)
 649 {
 650         struct smc_link_group *lgr = conn->lgr;
 651
 652         smc_ib_sync_sg_for_cpu(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
 653                                conn->rmb_desc, DMA_FROM_DEVICE);
 654 }
 655
 656 void smc_rmb_sync_sg_for_device(struct smc_connection *conn)
 657 {
 658         struct smc_link_group *lgr = conn->lgr;
 659
 660         smc_ib_sync_sg_for_device(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
 661                                   conn->rmb_desc, DMA_FROM_DEVICE);
 662 }
 663
 664 /* create the send and receive buffer for an SMC socket;
 665  * receive buffers are called RMBs;
 666  * (even though the SMC protocol allows more than one RMB-element per RMB,
 667  * the Linux implementation uses just one RMB-element per RMB, i.e. uses an
 668  * extra RMB for every connection in a link group
 669  */
 670 int smc_buf_create(struct smc_sock *smc)
 671 {
 672         int rc;
 673
 674         /* create send buffer */
 675         rc = __smc_buf_create(smc, false);
 676         if (rc)
 677                 return rc;
 678         /* create rmb */
 679         rc = __smc_buf_create(smc, true);
 680         if (rc)
 681                 smc_buf_free(smc->conn.sndbuf_desc,
 682                              &smc->conn.lgr->lnk[SMC_SINGLE_LINK], false);
 683         return rc;
 684 }
 685
 686 static inline int smc_rmb_reserve_rtoken_idx(struct smc_link_group *lgr)
 687 {
 688         int i;
 689
 690         for_each_clear_bit(i, lgr->rtokens_used_mask, SMC_RMBS_PER_LGR_MAX) {
 691                 if (!test_and_set_bit(i, lgr->rtokens_used_mask))
 692                         return i;
 693         }
 694         return -ENOSPC;
 695 }
 696
 697 /* save rkey and dma_addr received from peer during clc handshake */
 698 int smc_rmb_rtoken_handling(struct smc_connection *conn,
 699                             struct smc_clc_msg_accept_confirm *clc)
 700 {
 701         u64 dma_addr = be64_to_cpu(clc->rmb_dma_addr);
 702         struct smc_link_group *lgr = conn->lgr;
 703         u32 rkey = ntohl(clc->rmb_rkey);
 704         int i;
 705
 706         for (i = 0; i < SMC_RMBS_PER_LGR_MAX; i++) {
 707                 if ((lgr->rtokens[i][SMC_SINGLE_LINK].rkey == rkey) &&
 708                     (lgr->rtokens[i][SMC_SINGLE_LINK].dma_addr == dma_addr) &&
 709                     test_bit(i, lgr->rtokens_used_mask)) {
 710                         conn->rtoken_idx = i;
 711                         return 0;
 712                 }
 713         }
 714         conn->rtoken_idx = smc_rmb_reserve_rtoken_idx(lgr);
 715         if (conn->rtoken_idx < 0)
 716                 return conn->rtoken_idx;
 717         lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].rkey = rkey;
 718         lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].dma_addr = dma_addr;
 719         return 0;
 720 }