LXR linux/net/smc/smc

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Shared Memory Communications over RDMA (SMC-R) and RoCE
   4 *
   5 * Manage send buffer.
   6 * Producer:
   7 * Copy user space data into send buffer, if send buffer space available.
   8 * Consumer:
   9 * Trigger RDMA write into RMBE of peer and send CDC, if RMBE space available.
  10 *
  11 * Copyright IBM Corp. 2016
  12 *
  13 * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
  14 */
  15
  16#include <linux/net.h>
  17#include <linux/rcupdate.h>
  18#include <linux/workqueue.h>
  19#include <linux/sched/signal.h>
  20
  21#include <net/sock.h>
  22#include <net/tcp.h>
  23
  24#include "smc.h"
  25#include "smc_wr.h"
  26#include "smc_cdc.h"
  27#include "smc_close.h"
  28#include "smc_ism.h"
  29#include "smc_tx.h"
  30
  31#define SMC_TX_WORK_DELAY       0
  32#define SMC_TX_CORK_DELAY       (HZ >> 2)       /* 250 ms */
  33
  34/***************************** sndbuf producer *******************************/
  35
  36/* callback implementation for sk.sk_write_space()
  37 * to wakeup sndbuf producers that blocked with smc_tx_wait().
  38 * called under sk_socket lock.
  39 */
  40static void smc_tx_write_space(struct sock *sk)
  41{
  42        struct socket *sock = sk->sk_socket;
  43        struct smc_sock *smc = smc_sk(sk);
  44        struct socket_wq *wq;
  45
  46        /* similar to sk_stream_write_space */
  47        if (atomic_read(&smc->conn.sndbuf_space) && sock) {
  48                clear_bit(SOCK_NOSPACE, &sock->flags);
  49                rcu_read_lock();
  50                wq = rcu_dereference(sk->sk_wq);
  51                if (skwq_has_sleeper(wq))
  52                        wake_up_interruptible_poll(&wq->wait,
  53                                                   EPOLLOUT | EPOLLWRNORM |
  54                                                   EPOLLWRBAND);
  55                if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
  56                        sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
  57                rcu_read_unlock();
  58        }
  59}
  60
  61/* Wakeup sndbuf producers that blocked with smc_tx_wait().
  62 * Cf. tcp_data_snd_check()=>tcp_check_space()=>tcp_new_space().
  63 */
  64void smc_tx_sndbuf_nonfull(struct smc_sock *smc)
  65{
  66        if (smc->sk.sk_socket &&
  67            test_bit(SOCK_NOSPACE, &smc->sk.sk_socket->flags))
  68                smc->sk.sk_write_space(&smc->sk);
  69}
  70
  71/* blocks sndbuf producer until at least one byte of free space available
  72 * or urgent Byte was consumed
  73 */
  74static int smc_tx_wait(struct smc_sock *smc, int flags)
  75{
  76        DEFINE_WAIT_FUNC(wait, woken_wake_function);
  77        struct smc_connection *conn = &smc->conn;
  78        struct sock *sk = &smc->sk;
  79        long timeo;
  80        int rc = 0;
  81
  82        /* similar to sk_stream_wait_memory */
  83        timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
  84        add_wait_queue(sk_sleep(sk), &wait);
  85        while (1) {
  86                sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
  87                if (sk->sk_err ||
  88                    (sk->sk_shutdown & SEND_SHUTDOWN) ||
  89                    conn->killed ||
  90                    conn->local_tx_ctrl.conn_state_flags.peer_done_writing) {
  91                        rc = -EPIPE;
  92                        break;
  93                }
  94                if (smc_cdc_rxed_any_close(conn)) {
  95                        rc = -ECONNRESET;
  96                        break;
  97                }
  98                if (!timeo) {
  99                        /* ensure EPOLLOUT is subsequently generated */
 100                        set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 101                        rc = -EAGAIN;
 102                        break;
 103                }
 104                if (signal_pending(current)) {
 105                        rc = sock_intr_errno(timeo);
 106                        break;
 107                }
 108                sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 109                if (atomic_read(&conn->sndbuf_space) && !conn->urg_tx_pend)
 110                        break; /* at least 1 byte of free & no urgent data */
 111                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 112                sk_wait_event(sk, &timeo,
 113                              sk->sk_err ||
 114                              (sk->sk_shutdown & SEND_SHUTDOWN) ||
 115                              smc_cdc_rxed_any_close(conn) ||
 116                              (atomic_read(&conn->sndbuf_space) &&
 117                               !conn->urg_tx_pend),
 118                              &wait);
 119        }
 120        remove_wait_queue(sk_sleep(sk), &wait);
 121        return rc;
 122}
 123
 124static bool smc_tx_is_corked(struct smc_sock *smc)
 125{
 126        struct tcp_sock *tp = tcp_sk(smc->clcsock->sk);
 127
 128        return (tp->nonagle & TCP_NAGLE_CORK) ? true : false;
 129}
 130
 131/* sndbuf producer: main API called by socket layer.
 132 * called under sock lock.
 133 */
 134int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
 135{
 136        size_t copylen, send_done = 0, send_remaining = len;
 137        size_t chunk_len, chunk_off, chunk_len_sum;
 138        struct smc_connection *conn = &smc->conn;
 139        union smc_host_cursor prep;
 140        struct sock *sk = &smc->sk;
 141        char *sndbuf_base;
 142        int tx_cnt_prep;
 143        int writespace;
 144        int rc, chunk;
 145
 146        /* This should be in poll */
 147        sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 148
 149        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
 150                rc = -EPIPE;
 151                goto out_err;
 152        }
 153
 154        while (msg_data_left(msg)) {
 155                if (sk->sk_state == SMC_INIT)
 156                        return -ENOTCONN;
 157                if (smc->sk.sk_shutdown & SEND_SHUTDOWN ||
 158                    (smc->sk.sk_err == ECONNABORTED) ||
 159                    conn->killed)
 160                        return -EPIPE;
 161                if (smc_cdc_rxed_any_close(conn))
 162                        return send_done ?: -ECONNRESET;
 163
 164                if (msg->msg_flags & MSG_OOB)
 165                        conn->local_tx_ctrl.prod_flags.urg_data_pending = 1;
 166
 167                if (!atomic_read(&conn->sndbuf_space) || conn->urg_tx_pend) {
 168                        if (send_done)
 169                                return send_done;
 170                        rc = smc_tx_wait(smc, msg->msg_flags);
 171                        if (rc)
 172                                goto out_err;
 173                        continue;
 174                }
 175
 176                /* initialize variables for 1st iteration of subsequent loop */
 177                /* could be just 1 byte, even after smc_tx_wait above */
 178                writespace = atomic_read(&conn->sndbuf_space);
 179                /* not more than what user space asked for */
 180                copylen = min_t(size_t, send_remaining, writespace);
 181                /* determine start of sndbuf */
 182                sndbuf_base = conn->sndbuf_desc->cpu_addr;
 183                smc_curs_copy(&prep, &conn->tx_curs_prep, conn);
 184                tx_cnt_prep = prep.count;
 185                /* determine chunks where to write into sndbuf */
 186                /* either unwrapped case, or 1st chunk of wrapped case */
 187                chunk_len = min_t(size_t, copylen, conn->sndbuf_desc->len -
 188                                  tx_cnt_prep);
 189                chunk_len_sum = chunk_len;
 190                chunk_off = tx_cnt_prep;
 191                smc_sndbuf_sync_sg_for_cpu(conn);
 192                for (chunk = 0; chunk < 2; chunk++) {
 193                        rc = memcpy_from_msg(sndbuf_base + chunk_off,
 194                                             msg, chunk_len);
 195                        if (rc) {
 196                                smc_sndbuf_sync_sg_for_device(conn);
 197                                if (send_done)
 198                                        return send_done;
 199                                goto out_err;
 200                        }
 201                        send_done += chunk_len;
 202                        send_remaining -= chunk_len;
 203
 204                        if (chunk_len_sum == copylen)
 205                                break; /* either on 1st or 2nd iteration */
 206                        /* prepare next (== 2nd) iteration */
 207                        chunk_len = copylen - chunk_len; /* remainder */
 208                        chunk_len_sum += chunk_len;
 209                        chunk_off = 0; /* modulo offset in send ring buffer */
 210                }
 211                smc_sndbuf_sync_sg_for_device(conn);
 212                /* update cursors */
 213                smc_curs_add(conn->sndbuf_desc->len, &prep, copylen);
 214                smc_curs_copy(&conn->tx_curs_prep, &prep, conn);
 215                /* increased in send tasklet smc_cdc_tx_handler() */
 216                smp_mb__before_atomic();
 217                atomic_sub(copylen, &conn->sndbuf_space);
 218                /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 219                smp_mb__after_atomic();
 220                /* since we just produced more new data into sndbuf,
 221                 * trigger sndbuf consumer: RDMA write into peer RMBE and CDC
 222                 */
 223                if ((msg->msg_flags & MSG_OOB) && !send_remaining)
 224                        conn->urg_tx_pend = true;
 225                if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) &&
 226                    (atomic_read(&conn->sndbuf_space) >
 227                                                (conn->sndbuf_desc->len >> 1)))
 228                        /* for a corked socket defer the RDMA writes if there
 229                         * is still sufficient sndbuf_space available
 230                         */
 231                        queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
 232                                           SMC_TX_CORK_DELAY);
 233                else
 234                        smc_tx_sndbuf_nonempty(conn);
 235        } /* while (msg_data_left(msg)) */
 236
 237        return send_done;
 238
 239out_err:
 240        rc = sk_stream_error(sk, msg->msg_flags, rc);
 241        /* make sure we wake any epoll edge trigger waiter */
 242        if (unlikely(rc == -EAGAIN))
 243                sk->sk_write_space(sk);
 244        return rc;
 245}
 246
 247/***************************** sndbuf consumer *******************************/
 248
 249/* sndbuf consumer: actual data transfer of one target chunk with ISM write */
 250int smcd_tx_ism_write(struct smc_connection *conn, void *data, size_t len,
 251                      u32 offset, int signal)
 252{
 253        struct smc_ism_position pos;
 254        int rc;
 255
 256        memset(&pos, 0, sizeof(pos));
 257        pos.token = conn->peer_token;
 258        pos.index = conn->peer_rmbe_idx;
 259        pos.offset = conn->tx_off + offset;
 260        pos.signal = signal;
 261        rc = smc_ism_write(conn->lgr->smcd, &pos, data, len);
 262        if (rc)
 263                conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 264        return rc;
 265}
 266
 267/* sndbuf consumer: actual data transfer of one target chunk with RDMA write */
 268static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset,
 269                             int num_sges, struct ib_rdma_wr *rdma_wr)
 270{
 271        struct smc_link_group *lgr = conn->lgr;
 272        struct smc_link *link = conn->lnk;
 273        int rc;
 274
 275        rdma_wr->wr.wr_id = smc_wr_tx_get_next_wr_id(link);
 276        rdma_wr->wr.num_sge = num_sges;
 277        rdma_wr->remote_addr =
 278                lgr->rtokens[conn->rtoken_idx][link->link_idx].dma_addr +
 279                /* RMBE within RMB */
 280                conn->tx_off +
 281                /* offset within RMBE */
 282                peer_rmbe_offset;
 283        rdma_wr->rkey = lgr->rtokens[conn->rtoken_idx][link->link_idx].rkey;
 284        rc = ib_post_send(link->roce_qp, &rdma_wr->wr, NULL);
 285        if (rc)
 286                smcr_link_down_cond_sched(link);
 287        return rc;
 288}
 289
 290/* sndbuf consumer */
 291static inline void smc_tx_advance_cursors(struct smc_connection *conn,
 292                                          union smc_host_cursor *prod,
 293                                          union smc_host_cursor *sent,
 294                                          size_t len)
 295{
 296        smc_curs_add(conn->peer_rmbe_size, prod, len);
 297        /* increased in recv tasklet smc_cdc_msg_rcv() */
 298        smp_mb__before_atomic();
 299        /* data in flight reduces usable snd_wnd */
 300        atomic_sub(len, &conn->peer_rmbe_space);
 301        /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 302        smp_mb__after_atomic();
 303        smc_curs_add(conn->sndbuf_desc->len, sent, len);
 304}
 305
 306/* SMC-R helper for smc_tx_rdma_writes() */
 307static int smcr_tx_rdma_writes(struct smc_connection *conn, size_t len,
 308                               size_t src_off, size_t src_len,
 309                               size_t dst_off, size_t dst_len,
 310                               struct smc_rdma_wr *wr_rdma_buf)
 311{
 312        struct smc_link *link = conn->lnk;
 313
 314        dma_addr_t dma_addr =
 315                sg_dma_address(conn->sndbuf_desc->sgt[link->link_idx].sgl);
 316        int src_len_sum = src_len, dst_len_sum = dst_len;
 317        int sent_count = src_off;
 318        int srcchunk, dstchunk;
 319        int num_sges;
 320        int rc;
 321
 322        for (dstchunk = 0; dstchunk < 2; dstchunk++) {
 323                struct ib_sge *sge =
 324                        wr_rdma_buf->wr_tx_rdma[dstchunk].wr.sg_list;
 325
 326                num_sges = 0;
 327                for (srcchunk = 0; srcchunk < 2; srcchunk++) {
 328                        sge[srcchunk].addr = dma_addr + src_off;
 329                        sge[srcchunk].length = src_len;
 330                        num_sges++;
 331
 332                        src_off += src_len;
 333                        if (src_off >= conn->sndbuf_desc->len)
 334                                src_off -= conn->sndbuf_desc->len;
 335                                                /* modulo in send ring */
 336                        if (src_len_sum == dst_len)
 337                                break; /* either on 1st or 2nd iteration */
 338                        /* prepare next (== 2nd) iteration */
 339                        src_len = dst_len - src_len; /* remainder */
 340                        src_len_sum += src_len;
 341                }
 342                rc = smc_tx_rdma_write(conn, dst_off, num_sges,
 343                                       &wr_rdma_buf->wr_tx_rdma[dstchunk]);
 344                if (rc)
 345                        return rc;
 346                if (dst_len_sum == len)
 347                        break; /* either on 1st or 2nd iteration */
 348                /* prepare next (== 2nd) iteration */
 349                dst_off = 0; /* modulo offset in RMBE ring buffer */
 350                dst_len = len - dst_len; /* remainder */
 351                dst_len_sum += dst_len;
 352                src_len = min_t(int, dst_len, conn->sndbuf_desc->len -
 353                                sent_count);
 354                src_len_sum = src_len;
 355        }
 356        return 0;
 357}
 358
 359/* SMC-D helper for smc_tx_rdma_writes() */
 360static int smcd_tx_rdma_writes(struct smc_connection *conn, size_t len,
 361                               size_t src_off, size_t src_len,
 362                               size_t dst_off, size_t dst_len)
 363{
 364        int src_len_sum = src_len, dst_len_sum = dst_len;
 365        int srcchunk, dstchunk;
 366        int rc;
 367
 368        for (dstchunk = 0; dstchunk < 2; dstchunk++) {
 369                for (srcchunk = 0; srcchunk < 2; srcchunk++) {
 370                        void *data = conn->sndbuf_desc->cpu_addr + src_off;
 371
 372                        rc = smcd_tx_ism_write(conn, data, src_len, dst_off +
 373                                               sizeof(struct smcd_cdc_msg), 0);
 374                        if (rc)
 375                                return rc;
 376                        dst_off += src_len;
 377                        src_off += src_len;
 378                        if (src_off >= conn->sndbuf_desc->len)
 379                                src_off -= conn->sndbuf_desc->len;
 380                                                /* modulo in send ring */
 381                        if (src_len_sum == dst_len)
 382                                break; /* either on 1st or 2nd iteration */
 383                        /* prepare next (== 2nd) iteration */
 384                        src_len = dst_len - src_len; /* remainder */
 385                        src_len_sum += src_len;
 386                }
 387                if (dst_len_sum == len)
 388                        break; /* either on 1st or 2nd iteration */
 389                /* prepare next (== 2nd) iteration */
 390                dst_off = 0; /* modulo offset in RMBE ring buffer */
 391                dst_len = len - dst_len; /* remainder */
 392                dst_len_sum += dst_len;
 393                src_len = min_t(int, dst_len, conn->sndbuf_desc->len - src_off);
 394                src_len_sum = src_len;
 395        }
 396        return 0;
 397}
 398
 399/* sndbuf consumer: prepare all necessary (src&dst) chunks of data transmit;
 400 * usable snd_wnd as max transmit
 401 */
 402static int smc_tx_rdma_writes(struct smc_connection *conn,
 403                              struct smc_rdma_wr *wr_rdma_buf)
 404{
 405        size_t len, src_len, dst_off, dst_len; /* current chunk values */
 406        union smc_host_cursor sent, prep, prod, cons;
 407        struct smc_cdc_producer_flags *pflags;
 408        int to_send, rmbespace;
 409        int rc;
 410
 411        /* source: sndbuf */
 412        smc_curs_copy(&sent, &conn->tx_curs_sent, conn);
 413        smc_curs_copy(&prep, &conn->tx_curs_prep, conn);
 414        /* cf. wmem_alloc - (snd_max - snd_una) */
 415        to_send = smc_curs_diff(conn->sndbuf_desc->len, &sent, &prep);
 416        if (to_send <= 0)
 417                return 0;
 418
 419        /* destination: RMBE */
 420        /* cf. snd_wnd */
 421        rmbespace = atomic_read(&conn->peer_rmbe_space);
 422        if (rmbespace <= 0)
 423                return 0;
 424        smc_curs_copy(&prod, &conn->local_tx_ctrl.prod, conn);
 425        smc_curs_copy(&cons, &conn->local_rx_ctrl.cons, conn);
 426
 427        /* if usable snd_wnd closes ask peer to advertise once it opens again */
 428        pflags = &conn->local_tx_ctrl.prod_flags;
 429        pflags->write_blocked = (to_send >= rmbespace);
 430        /* cf. usable snd_wnd */
 431        len = min(to_send, rmbespace);
 432
 433        /* initialize variables for first iteration of subsequent nested loop */
 434        dst_off = prod.count;
 435        if (prod.wrap == cons.wrap) {
 436                /* the filled destination area is unwrapped,
 437                 * hence the available free destination space is wrapped
 438                 * and we need 2 destination chunks of sum len; start with 1st
 439                 * which is limited by what's available in sndbuf
 440                 */
 441                dst_len = min_t(size_t,
 442                                conn->peer_rmbe_size - prod.count, len);
 443        } else {
 444                /* the filled destination area is wrapped,
 445                 * hence the available free destination space is unwrapped
 446                 * and we need a single destination chunk of entire len
 447                 */
 448                dst_len = len;
 449        }
 450        /* dst_len determines the maximum src_len */
 451        if (sent.count + dst_len <= conn->sndbuf_desc->len) {
 452                /* unwrapped src case: single chunk of entire dst_len */
 453                src_len = dst_len;
 454        } else {
 455                /* wrapped src case: 2 chunks of sum dst_len; start with 1st: */
 456                src_len = conn->sndbuf_desc->len - sent.count;
 457        }
 458
 459        if (conn->lgr->is_smcd)
 460                rc = smcd_tx_rdma_writes(conn, len, sent.count, src_len,
 461                                         dst_off, dst_len);
 462        else
 463                rc = smcr_tx_rdma_writes(conn, len, sent.count, src_len,
 464                                         dst_off, dst_len, wr_rdma_buf);
 465        if (rc)
 466                return rc;
 467
 468        if (conn->urg_tx_pend && len == to_send)
 469                pflags->urg_data_present = 1;
 470        smc_tx_advance_cursors(conn, &prod, &sent, len);
 471        /* update connection's cursors with advanced local cursors */
 472        smc_curs_copy(&conn->local_tx_ctrl.prod, &prod, conn);
 473                                                        /* dst: peer RMBE */
 474        smc_curs_copy(&conn->tx_curs_sent, &sent, conn);/* src: local sndbuf */
 475
 476        return 0;
 477}
 478
 479/* Wakeup sndbuf consumers from any context (IRQ or process)
 480 * since there is more data to transmit; usable snd_wnd as max transmit
 481 */
 482static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
 483{
 484        struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags;
 485        struct smc_link *link = conn->lnk;
 486        struct smc_rdma_wr *wr_rdma_buf;
 487        struct smc_cdc_tx_pend *pend;
 488        struct smc_wr_buf *wr_buf;
 489        int rc;
 490
 491        rc = smc_cdc_get_free_slot(conn, link, &wr_buf, &wr_rdma_buf, &pend);
 492        if (rc < 0) {
 493                if (rc == -EBUSY) {
 494                        struct smc_sock *smc =
 495                                container_of(conn, struct smc_sock, conn);
 496
 497                        if (smc->sk.sk_err == ECONNABORTED)
 498                                return sock_error(&smc->sk);
 499                        if (conn->killed)
 500                                return -EPIPE;
 501                        rc = 0;
 502                        mod_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
 503                                         SMC_TX_WORK_DELAY);
 504                }
 505                return rc;
 506        }
 507
 508        spin_lock_bh(&conn->send_lock);
 509        if (link != conn->lnk) {
 510                /* link of connection changed, tx_work will restart */
 511                smc_wr_tx_put_slot(link,
 512                                   (struct smc_wr_tx_pend_priv *)pend);
 513                rc = -ENOLINK;
 514                goto out_unlock;
 515        }
 516        if (!pflags->urg_data_present) {
 517                rc = smc_tx_rdma_writes(conn, wr_rdma_buf);
 518                if (rc) {
 519                        smc_wr_tx_put_slot(link,
 520                                           (struct smc_wr_tx_pend_priv *)pend);
 521                        goto out_unlock;
 522                }
 523        }
 524
 525        rc = smc_cdc_msg_send(conn, wr_buf, pend);
 526        if (!rc && pflags->urg_data_present) {
 527                pflags->urg_data_pending = 0;
 528                pflags->urg_data_present = 0;
 529        }
 530
 531out_unlock:
 532        spin_unlock_bh(&conn->send_lock);
 533        return rc;
 534}
 535
 536static int smcd_tx_sndbuf_nonempty(struct smc_connection *conn)
 537{
 538        struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags;
 539        int rc = 0;
 540
 541        spin_lock_bh(&conn->send_lock);
 542        if (!pflags->urg_data_present)
 543                rc = smc_tx_rdma_writes(conn, NULL);
 544        if (!rc)
 545                rc = smcd_cdc_msg_send(conn);
 546
 547        if (!rc && pflags->urg_data_present) {
 548                pflags->urg_data_pending = 0;
 549                pflags->urg_data_present = 0;
 550        }
 551        spin_unlock_bh(&conn->send_lock);
 552        return rc;
 553}
 554
 555int smc_tx_sndbuf_nonempty(struct smc_connection *conn)
 556{
 557        int rc;
 558
 559        if (conn->killed ||
 560            conn->local_rx_ctrl.conn_state_flags.peer_conn_abort)
 561                return -EPIPE;  /* connection being aborted */
 562        if (conn->lgr->is_smcd)
 563                rc = smcd_tx_sndbuf_nonempty(conn);
 564        else
 565                rc = smcr_tx_sndbuf_nonempty(conn);
 566
 567        if (!rc) {
 568                /* trigger socket release if connection is closing */
 569                struct smc_sock *smc = container_of(conn, struct smc_sock,
 570                                                    conn);
 571                smc_close_wake_tx_prepared(smc);
 572        }
 573        return rc;
 574}
 575
 576/* Wakeup sndbuf consumers from process context
 577 * since there is more data to transmit
 578 */
 579void smc_tx_work(struct work_struct *work)
 580{
 581        struct smc_connection *conn = container_of(to_delayed_work(work),
 582                                                   struct smc_connection,
 583                                                   tx_work);
 584        struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 585        int rc;
 586
 587        lock_sock(&smc->sk);
 588        if (smc->sk.sk_err)
 589                goto out;
 590
 591        rc = smc_tx_sndbuf_nonempty(conn);
 592        if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked &&
 593            !atomic_read(&conn->bytes_to_rcv))
 594                conn->local_rx_ctrl.prod_flags.write_blocked = 0;
 595
 596out:
 597        release_sock(&smc->sk);
 598}
 599
 600void smc_tx_consumer_update(struct smc_connection *conn, bool force)
 601{
 602        union smc_host_cursor cfed, cons, prod;
 603        int sender_free = conn->rmb_desc->len;
 604        int to_confirm;
 605
 606        smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn);
 607        smc_curs_copy(&cfed, &conn->rx_curs_confirmed, conn);
 608        to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons);
 609        if (to_confirm > conn->rmbe_update_limit) {
 610                smc_curs_copy(&prod, &conn->local_rx_ctrl.prod, conn);
 611                sender_free = conn->rmb_desc->len -
 612                              smc_curs_diff_large(conn->rmb_desc->len,
 613                                                  &cfed, &prod);
 614        }
 615
 616        if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 617            force ||
 618            ((to_confirm > conn->rmbe_update_limit) &&
 619             ((sender_free <= (conn->rmb_desc->len / 2)) ||
 620              conn->local_rx_ctrl.prod_flags.write_blocked))) {
 621                if (conn->killed ||
 622                    conn->local_rx_ctrl.conn_state_flags.peer_conn_abort)
 623                        return;
 624                if ((smc_cdc_get_slot_and_msg_send(conn) < 0) &&
 625                    !conn->killed) {
 626                        queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
 627                                           SMC_TX_WORK_DELAY);
 628                        return;
 629                }
 630        }
 631        if (conn->local_rx_ctrl.prod_flags.write_blocked &&
 632            !atomic_read(&conn->bytes_to_rcv))
 633                conn->local_rx_ctrl.prod_flags.write_blocked = 0;
 634}
 635
 636/***************************** send initialize *******************************/
 637
 638/* Initialize send properties on connection establishment. NB: not __init! */
 639void smc_tx_init(struct smc_sock *smc)
 640{
 641        smc->sk.sk_write_space = smc_tx_write_space;
 642}
 643