linux/net/smc/smc_tx.c
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   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#include "smc_stats.h"
  31
  32#define SMC_TX_WORK_DELAY       0
  33#define SMC_TX_CORK_DELAY       (HZ >> 2)       /* 250 ms */
  34
  35/***************************** sndbuf producer *******************************/
  36
  37/* callback implementation for sk.sk_write_space()
  38 * to wakeup sndbuf producers that blocked with smc_tx_wait().
  39 * called under sk_socket lock.
  40 */
  41static void smc_tx_write_space(struct sock *sk)
  42{
  43        struct socket *sock = sk->sk_socket;
  44        struct smc_sock *smc = smc_sk(sk);
  45        struct socket_wq *wq;
  46
  47        /* similar to sk_stream_write_space */
  48        if (atomic_read(&smc->conn.sndbuf_space) && sock) {
  49                if (test_bit(SOCK_NOSPACE, &sock->flags))
  50                        SMC_STAT_RMB_TX_FULL(smc, !smc->conn.lnk);
  51                clear_bit(SOCK_NOSPACE, &sock->flags);
  52                rcu_read_lock();
  53                wq = rcu_dereference(sk->sk_wq);
  54                if (skwq_has_sleeper(wq))
  55                        wake_up_interruptible_poll(&wq->wait,
  56                                                   EPOLLOUT | EPOLLWRNORM |
  57                                                   EPOLLWRBAND);
  58                if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
  59                        sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
  60                rcu_read_unlock();
  61        }
  62}
  63
  64/* Wakeup sndbuf producers that blocked with smc_tx_wait().
  65 * Cf. tcp_data_snd_check()=>tcp_check_space()=>tcp_new_space().
  66 */
  67void smc_tx_sndbuf_nonfull(struct smc_sock *smc)
  68{
  69        if (smc->sk.sk_socket &&
  70            test_bit(SOCK_NOSPACE, &smc->sk.sk_socket->flags))
  71                smc->sk.sk_write_space(&smc->sk);
  72}
  73
  74/* blocks sndbuf producer until at least one byte of free space available
  75 * or urgent Byte was consumed
  76 */
  77static int smc_tx_wait(struct smc_sock *smc, int flags)
  78{
  79        DEFINE_WAIT_FUNC(wait, woken_wake_function);
  80        struct smc_connection *conn = &smc->conn;
  81        struct sock *sk = &smc->sk;
  82        long timeo;
  83        int rc = 0;
  84
  85        /* similar to sk_stream_wait_memory */
  86        timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
  87        add_wait_queue(sk_sleep(sk), &wait);
  88        while (1) {
  89                sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
  90                if (sk->sk_err ||
  91                    (sk->sk_shutdown & SEND_SHUTDOWN) ||
  92                    conn->killed ||
  93                    conn->local_tx_ctrl.conn_state_flags.peer_done_writing) {
  94                        rc = -EPIPE;
  95                        break;
  96                }
  97                if (smc_cdc_rxed_any_close(conn)) {
  98                        rc = -ECONNRESET;
  99                        break;
 100                }
 101                if (!timeo) {
 102                        /* ensure EPOLLOUT is subsequently generated */
 103                        set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 104                        rc = -EAGAIN;
 105                        break;
 106                }
 107                if (signal_pending(current)) {
 108                        rc = sock_intr_errno(timeo);
 109                        break;
 110                }
 111                sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 112                if (atomic_read(&conn->sndbuf_space) && !conn->urg_tx_pend)
 113                        break; /* at least 1 byte of free & no urgent data */
 114                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 115                sk_wait_event(sk, &timeo,
 116                              sk->sk_err ||
 117                              (sk->sk_shutdown & SEND_SHUTDOWN) ||
 118                              smc_cdc_rxed_any_close(conn) ||
 119                              (atomic_read(&conn->sndbuf_space) &&
 120                               !conn->urg_tx_pend),
 121                              &wait);
 122        }
 123        remove_wait_queue(sk_sleep(sk), &wait);
 124        return rc;
 125}
 126
 127static bool smc_tx_is_corked(struct smc_sock *smc)
 128{
 129        struct tcp_sock *tp = tcp_sk(smc->clcsock->sk);
 130
 131        return (tp->nonagle & TCP_NAGLE_CORK) ? true : false;
 132}
 133
 134/* sndbuf producer: main API called by socket layer.
 135 * called under sock lock.
 136 */
 137int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
 138{
 139        size_t copylen, send_done = 0, send_remaining = len;
 140        size_t chunk_len, chunk_off, chunk_len_sum;
 141        struct smc_connection *conn = &smc->conn;
 142        union smc_host_cursor prep;
 143        struct sock *sk = &smc->sk;
 144        char *sndbuf_base;
 145        int tx_cnt_prep;
 146        int writespace;
 147        int rc, chunk;
 148
 149        /* This should be in poll */
 150        sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 151
 152        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
 153                rc = -EPIPE;
 154                goto out_err;
 155        }
 156
 157        if (sk->sk_state == SMC_INIT)
 158                return -ENOTCONN;
 159
 160        if (len > conn->sndbuf_desc->len)
 161                SMC_STAT_RMB_TX_SIZE_SMALL(smc, !conn->lnk);
 162
 163        if (len > conn->peer_rmbe_size)
 164                SMC_STAT_RMB_TX_PEER_SIZE_SMALL(smc, !conn->lnk);
 165
 166        if (msg->msg_flags & MSG_OOB)
 167                SMC_STAT_INC(smc, urg_data_cnt);
 168
 169        while (msg_data_left(msg)) {
 170                if (smc->sk.sk_shutdown & SEND_SHUTDOWN ||
 171                    (smc->sk.sk_err == ECONNABORTED) ||
 172                    conn->killed)
 173                        return -EPIPE;
 174                if (smc_cdc_rxed_any_close(conn))
 175                        return send_done ?: -ECONNRESET;
 176
 177                if (msg->msg_flags & MSG_OOB)
 178                        conn->local_tx_ctrl.prod_flags.urg_data_pending = 1;
 179
 180                if (!atomic_read(&conn->sndbuf_space) || conn->urg_tx_pend) {
 181                        if (send_done)
 182                                return send_done;
 183                        rc = smc_tx_wait(smc, msg->msg_flags);
 184                        if (rc)
 185                                goto out_err;
 186                        continue;
 187                }
 188
 189                /* initialize variables for 1st iteration of subsequent loop */
 190                /* could be just 1 byte, even after smc_tx_wait above */
 191                writespace = atomic_read(&conn->sndbuf_space);
 192                /* not more than what user space asked for */
 193                copylen = min_t(size_t, send_remaining, writespace);
 194                /* determine start of sndbuf */
 195                sndbuf_base = conn->sndbuf_desc->cpu_addr;
 196                smc_curs_copy(&prep, &conn->tx_curs_prep, conn);
 197                tx_cnt_prep = prep.count;
 198                /* determine chunks where to write into sndbuf */
 199                /* either unwrapped case, or 1st chunk of wrapped case */
 200                chunk_len = min_t(size_t, copylen, conn->sndbuf_desc->len -
 201                                  tx_cnt_prep);
 202                chunk_len_sum = chunk_len;
 203                chunk_off = tx_cnt_prep;
 204                smc_sndbuf_sync_sg_for_cpu(conn);
 205                for (chunk = 0; chunk < 2; chunk++) {
 206                        rc = memcpy_from_msg(sndbuf_base + chunk_off,
 207                                             msg, chunk_len);
 208                        if (rc) {
 209                                smc_sndbuf_sync_sg_for_device(conn);
 210                                if (send_done)
 211                                        return send_done;
 212                                goto out_err;
 213                        }
 214                        send_done += chunk_len;
 215                        send_remaining -= chunk_len;
 216
 217                        if (chunk_len_sum == copylen)
 218                                break; /* either on 1st or 2nd iteration */
 219                        /* prepare next (== 2nd) iteration */
 220                        chunk_len = copylen - chunk_len; /* remainder */
 221                        chunk_len_sum += chunk_len;
 222                        chunk_off = 0; /* modulo offset in send ring buffer */
 223                }
 224                smc_sndbuf_sync_sg_for_device(conn);
 225                /* update cursors */
 226                smc_curs_add(conn->sndbuf_desc->len, &prep, copylen);
 227                smc_curs_copy(&conn->tx_curs_prep, &prep, conn);
 228                /* increased in send tasklet smc_cdc_tx_handler() */
 229                smp_mb__before_atomic();
 230                atomic_sub(copylen, &conn->sndbuf_space);
 231                /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 232                smp_mb__after_atomic();
 233                /* since we just produced more new data into sndbuf,
 234                 * trigger sndbuf consumer: RDMA write into peer RMBE and CDC
 235                 */
 236                if ((msg->msg_flags & MSG_OOB) && !send_remaining)
 237                        conn->urg_tx_pend = true;
 238                if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) &&
 239                    (atomic_read(&conn->sndbuf_space) >
 240                                                (conn->sndbuf_desc->len >> 1)))
 241                        /* for a corked socket defer the RDMA writes if there
 242                         * is still sufficient sndbuf_space available
 243                         */
 244                        queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
 245                                           SMC_TX_CORK_DELAY);
 246                else
 247                        smc_tx_sndbuf_nonempty(conn);
 248        } /* while (msg_data_left(msg)) */
 249
 250        return send_done;
 251
 252out_err:
 253        rc = sk_stream_error(sk, msg->msg_flags, rc);
 254        /* make sure we wake any epoll edge trigger waiter */
 255        if (unlikely(rc == -EAGAIN))
 256                sk->sk_write_space(sk);
 257        return rc;
 258}
 259
 260/***************************** sndbuf consumer *******************************/
 261
 262/* sndbuf consumer: actual data transfer of one target chunk with ISM write */
 263int smcd_tx_ism_write(struct smc_connection *conn, void *data, size_t len,
 264                      u32 offset, int signal)
 265{
 266        struct smc_ism_position pos;
 267        int rc;
 268
 269        memset(&pos, 0, sizeof(pos));
 270        pos.token = conn->peer_token;
 271        pos.index = conn->peer_rmbe_idx;
 272        pos.offset = conn->tx_off + offset;
 273        pos.signal = signal;
 274        rc = smc_ism_write(conn->lgr->smcd, &pos, data, len);
 275        if (rc)
 276                conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 277        return rc;
 278}
 279
 280/* sndbuf consumer: actual data transfer of one target chunk with RDMA write */
 281static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset,
 282                             int num_sges, struct ib_rdma_wr *rdma_wr)
 283{
 284        struct smc_link_group *lgr = conn->lgr;
 285        struct smc_link *link = conn->lnk;
 286        int rc;
 287
 288        rdma_wr->wr.wr_id = smc_wr_tx_get_next_wr_id(link);
 289        rdma_wr->wr.num_sge = num_sges;
 290        rdma_wr->remote_addr =
 291                lgr->rtokens[conn->rtoken_idx][link->link_idx].dma_addr +
 292                /* RMBE within RMB */
 293                conn->tx_off +
 294                /* offset within RMBE */
 295                peer_rmbe_offset;
 296        rdma_wr->rkey = lgr->rtokens[conn->rtoken_idx][link->link_idx].rkey;
 297        rc = ib_post_send(link->roce_qp, &rdma_wr->wr, NULL);
 298        if (rc)
 299                smcr_link_down_cond_sched(link);
 300        return rc;
 301}
 302
 303/* sndbuf consumer */
 304static inline void smc_tx_advance_cursors(struct smc_connection *conn,
 305                                          union smc_host_cursor *prod,
 306                                          union smc_host_cursor *sent,
 307                                          size_t len)
 308{
 309        smc_curs_add(conn->peer_rmbe_size, prod, len);
 310        /* increased in recv tasklet smc_cdc_msg_rcv() */
 311        smp_mb__before_atomic();
 312        /* data in flight reduces usable snd_wnd */
 313        atomic_sub(len, &conn->peer_rmbe_space);
 314        /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 315        smp_mb__after_atomic();
 316        smc_curs_add(conn->sndbuf_desc->len, sent, len);
 317}
 318
 319/* SMC-R helper for smc_tx_rdma_writes() */
 320static int smcr_tx_rdma_writes(struct smc_connection *conn, size_t len,
 321                               size_t src_off, size_t src_len,
 322                               size_t dst_off, size_t dst_len,
 323                               struct smc_rdma_wr *wr_rdma_buf)
 324{
 325        struct smc_link *link = conn->lnk;
 326
 327        dma_addr_t dma_addr =
 328                sg_dma_address(conn->sndbuf_desc->sgt[link->link_idx].sgl);
 329        int src_len_sum = src_len, dst_len_sum = dst_len;
 330        int sent_count = src_off;
 331        int srcchunk, dstchunk;
 332        int num_sges;
 333        int rc;
 334
 335        for (dstchunk = 0; dstchunk < 2; dstchunk++) {
 336                struct ib_sge *sge =
 337                        wr_rdma_buf->wr_tx_rdma[dstchunk].wr.sg_list;
 338
 339                num_sges = 0;
 340                for (srcchunk = 0; srcchunk < 2; srcchunk++) {
 341                        sge[srcchunk].addr = dma_addr + src_off;
 342                        sge[srcchunk].length = src_len;
 343                        num_sges++;
 344
 345                        src_off += src_len;
 346                        if (src_off >= conn->sndbuf_desc->len)
 347                                src_off -= conn->sndbuf_desc->len;
 348                                                /* modulo in send ring */
 349                        if (src_len_sum == dst_len)
 350                                break; /* either on 1st or 2nd iteration */
 351                        /* prepare next (== 2nd) iteration */
 352                        src_len = dst_len - src_len; /* remainder */
 353                        src_len_sum += src_len;
 354                }
 355                rc = smc_tx_rdma_write(conn, dst_off, num_sges,
 356                                       &wr_rdma_buf->wr_tx_rdma[dstchunk]);
 357                if (rc)
 358                        return rc;
 359                if (dst_len_sum == len)
 360                        break; /* either on 1st or 2nd iteration */
 361                /* prepare next (== 2nd) iteration */
 362                dst_off = 0; /* modulo offset in RMBE ring buffer */
 363                dst_len = len - dst_len; /* remainder */
 364                dst_len_sum += dst_len;
 365                src_len = min_t(int, dst_len, conn->sndbuf_desc->len -
 366                                sent_count);
 367                src_len_sum = src_len;
 368        }
 369        return 0;
 370}
 371
 372/* SMC-D helper for smc_tx_rdma_writes() */
 373static int smcd_tx_rdma_writes(struct smc_connection *conn, size_t len,
 374                               size_t src_off, size_t src_len,
 375                               size_t dst_off, size_t dst_len)
 376{
 377        int src_len_sum = src_len, dst_len_sum = dst_len;
 378        int srcchunk, dstchunk;
 379        int rc;
 380
 381        for (dstchunk = 0; dstchunk < 2; dstchunk++) {
 382                for (srcchunk = 0; srcchunk < 2; srcchunk++) {
 383                        void *data = conn->sndbuf_desc->cpu_addr + src_off;
 384
 385                        rc = smcd_tx_ism_write(conn, data, src_len, dst_off +
 386                                               sizeof(struct smcd_cdc_msg), 0);
 387                        if (rc)
 388                                return rc;
 389                        dst_off += src_len;
 390                        src_off += src_len;
 391                        if (src_off >= conn->sndbuf_desc->len)
 392                                src_off -= conn->sndbuf_desc->len;
 393                                                /* modulo in send ring */
 394                        if (src_len_sum == dst_len)
 395                                break; /* either on 1st or 2nd iteration */
 396                        /* prepare next (== 2nd) iteration */
 397                        src_len = dst_len - src_len; /* remainder */
 398                        src_len_sum += src_len;
 399                }
 400                if (dst_len_sum == len)
 401                        break; /* either on 1st or 2nd iteration */
 402                /* prepare next (== 2nd) iteration */
 403                dst_off = 0; /* modulo offset in RMBE ring buffer */
 404                dst_len = len - dst_len; /* remainder */
 405                dst_len_sum += dst_len;
 406                src_len = min_t(int, dst_len, conn->sndbuf_desc->len - src_off);
 407                src_len_sum = src_len;
 408        }
 409        return 0;
 410}
 411
 412/* sndbuf consumer: prepare all necessary (src&dst) chunks of data transmit;
 413 * usable snd_wnd as max transmit
 414 */
 415static int smc_tx_rdma_writes(struct smc_connection *conn,
 416                              struct smc_rdma_wr *wr_rdma_buf)
 417{
 418        size_t len, src_len, dst_off, dst_len; /* current chunk values */
 419        union smc_host_cursor sent, prep, prod, cons;
 420        struct smc_cdc_producer_flags *pflags;
 421        int to_send, rmbespace;
 422        int rc;
 423
 424        /* source: sndbuf */
 425        smc_curs_copy(&sent, &conn->tx_curs_sent, conn);
 426        smc_curs_copy(&prep, &conn->tx_curs_prep, conn);
 427        /* cf. wmem_alloc - (snd_max - snd_una) */
 428        to_send = smc_curs_diff(conn->sndbuf_desc->len, &sent, &prep);
 429        if (to_send <= 0)
 430                return 0;
 431
 432        /* destination: RMBE */
 433        /* cf. snd_wnd */
 434        rmbespace = atomic_read(&conn->peer_rmbe_space);
 435        if (rmbespace <= 0) {
 436                struct smc_sock *smc = container_of(conn, struct smc_sock,
 437                                                    conn);
 438                SMC_STAT_RMB_TX_PEER_FULL(smc, !conn->lnk);
 439                return 0;
 440        }
 441        smc_curs_copy(&prod, &conn->local_tx_ctrl.prod, conn);
 442        smc_curs_copy(&cons, &conn->local_rx_ctrl.cons, conn);
 443
 444        /* if usable snd_wnd closes ask peer to advertise once it opens again */
 445        pflags = &conn->local_tx_ctrl.prod_flags;
 446        pflags->write_blocked = (to_send >= rmbespace);
 447        /* cf. usable snd_wnd */
 448        len = min(to_send, rmbespace);
 449
 450        /* initialize variables for first iteration of subsequent nested loop */
 451        dst_off = prod.count;
 452        if (prod.wrap == cons.wrap) {
 453                /* the filled destination area is unwrapped,
 454                 * hence the available free destination space is wrapped
 455                 * and we need 2 destination chunks of sum len; start with 1st
 456                 * which is limited by what's available in sndbuf
 457                 */
 458                dst_len = min_t(size_t,
 459                                conn->peer_rmbe_size - prod.count, len);
 460        } else {
 461                /* the filled destination area is wrapped,
 462                 * hence the available free destination space is unwrapped
 463                 * and we need a single destination chunk of entire len
 464                 */
 465                dst_len = len;
 466        }
 467        /* dst_len determines the maximum src_len */
 468        if (sent.count + dst_len <= conn->sndbuf_desc->len) {
 469                /* unwrapped src case: single chunk of entire dst_len */
 470                src_len = dst_len;
 471        } else {
 472                /* wrapped src case: 2 chunks of sum dst_len; start with 1st: */
 473                src_len = conn->sndbuf_desc->len - sent.count;
 474        }
 475
 476        if (conn->lgr->is_smcd)
 477                rc = smcd_tx_rdma_writes(conn, len, sent.count, src_len,
 478                                         dst_off, dst_len);
 479        else
 480                rc = smcr_tx_rdma_writes(conn, len, sent.count, src_len,
 481                                         dst_off, dst_len, wr_rdma_buf);
 482        if (rc)
 483                return rc;
 484
 485        if (conn->urg_tx_pend && len == to_send)
 486                pflags->urg_data_present = 1;
 487        smc_tx_advance_cursors(conn, &prod, &sent, len);
 488        /* update connection's cursors with advanced local cursors */
 489        smc_curs_copy(&conn->local_tx_ctrl.prod, &prod, conn);
 490                                                        /* dst: peer RMBE */
 491        smc_curs_copy(&conn->tx_curs_sent, &sent, conn);/* src: local sndbuf */
 492
 493        return 0;
 494}
 495
 496/* Wakeup sndbuf consumers from any context (IRQ or process)
 497 * since there is more data to transmit; usable snd_wnd as max transmit
 498 */
 499static int _smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
 500{
 501        struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags;
 502        struct smc_link *link = conn->lnk;
 503        struct smc_rdma_wr *wr_rdma_buf;
 504        struct smc_cdc_tx_pend *pend;
 505        struct smc_wr_buf *wr_buf;
 506        int rc;
 507
 508        rc = smc_cdc_get_free_slot(conn, link, &wr_buf, &wr_rdma_buf, &pend);
 509        if (rc < 0) {
 510                if (rc == -EBUSY) {
 511                        struct smc_sock *smc =
 512                                container_of(conn, struct smc_sock, conn);
 513
 514                        if (smc->sk.sk_err == ECONNABORTED)
 515                                return sock_error(&smc->sk);
 516                        if (conn->killed)
 517                                return -EPIPE;
 518                        rc = 0;
 519                        mod_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
 520                                         SMC_TX_WORK_DELAY);
 521                }
 522                return rc;
 523        }
 524
 525        spin_lock_bh(&conn->send_lock);
 526        if (link != conn->lnk) {
 527                /* link of connection changed, tx_work will restart */
 528                smc_wr_tx_put_slot(link,
 529                                   (struct smc_wr_tx_pend_priv *)pend);
 530                rc = -ENOLINK;
 531                goto out_unlock;
 532        }
 533        if (!pflags->urg_data_present) {
 534                rc = smc_tx_rdma_writes(conn, wr_rdma_buf);
 535                if (rc) {
 536                        smc_wr_tx_put_slot(link,
 537                                           (struct smc_wr_tx_pend_priv *)pend);
 538                        goto out_unlock;
 539                }
 540        }
 541
 542        rc = smc_cdc_msg_send(conn, wr_buf, pend);
 543        if (!rc && pflags->urg_data_present) {
 544                pflags->urg_data_pending = 0;
 545                pflags->urg_data_present = 0;
 546        }
 547
 548out_unlock:
 549        spin_unlock_bh(&conn->send_lock);
 550        return rc;
 551}
 552
 553static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
 554{
 555        struct smc_link *link = conn->lnk;
 556        int rc = -ENOLINK;
 557
 558        if (!link)
 559                return rc;
 560
 561        atomic_inc(&link->wr_tx_refcnt);
 562        if (smc_link_usable(link))
 563                rc = _smcr_tx_sndbuf_nonempty(conn);
 564        if (atomic_dec_and_test(&link->wr_tx_refcnt))
 565                wake_up_all(&link->wr_tx_wait);
 566        return rc;
 567}
 568
 569static int smcd_tx_sndbuf_nonempty(struct smc_connection *conn)
 570{
 571        struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags;
 572        int rc = 0;
 573
 574        spin_lock_bh(&conn->send_lock);
 575        if (!pflags->urg_data_present)
 576                rc = smc_tx_rdma_writes(conn, NULL);
 577        if (!rc)
 578                rc = smcd_cdc_msg_send(conn);
 579
 580        if (!rc && pflags->urg_data_present) {
 581                pflags->urg_data_pending = 0;
 582                pflags->urg_data_present = 0;
 583        }
 584        spin_unlock_bh(&conn->send_lock);
 585        return rc;
 586}
 587
 588int smc_tx_sndbuf_nonempty(struct smc_connection *conn)
 589{
 590        int rc;
 591
 592        if (conn->killed ||
 593            conn->local_rx_ctrl.conn_state_flags.peer_conn_abort)
 594                return -EPIPE;  /* connection being aborted */
 595        if (conn->lgr->is_smcd)
 596                rc = smcd_tx_sndbuf_nonempty(conn);
 597        else
 598                rc = smcr_tx_sndbuf_nonempty(conn);
 599
 600        if (!rc) {
 601                /* trigger socket release if connection is closing */
 602                struct smc_sock *smc = container_of(conn, struct smc_sock,
 603                                                    conn);
 604                smc_close_wake_tx_prepared(smc);
 605        }
 606        return rc;
 607}
 608
 609/* Wakeup sndbuf consumers from process context
 610 * since there is more data to transmit
 611 */
 612void smc_tx_work(struct work_struct *work)
 613{
 614        struct smc_connection *conn = container_of(to_delayed_work(work),
 615                                                   struct smc_connection,
 616                                                   tx_work);
 617        struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 618        int rc;
 619
 620        lock_sock(&smc->sk);
 621        if (smc->sk.sk_err)
 622                goto out;
 623
 624        rc = smc_tx_sndbuf_nonempty(conn);
 625        if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked &&
 626            !atomic_read(&conn->bytes_to_rcv))
 627                conn->local_rx_ctrl.prod_flags.write_blocked = 0;
 628
 629out:
 630        release_sock(&smc->sk);
 631}
 632
 633void smc_tx_consumer_update(struct smc_connection *conn, bool force)
 634{
 635        union smc_host_cursor cfed, cons, prod;
 636        int sender_free = conn->rmb_desc->len;
 637        int to_confirm;
 638
 639        smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn);
 640        smc_curs_copy(&cfed, &conn->rx_curs_confirmed, conn);
 641        to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons);
 642        if (to_confirm > conn->rmbe_update_limit) {
 643                smc_curs_copy(&prod, &conn->local_rx_ctrl.prod, conn);
 644                sender_free = conn->rmb_desc->len -
 645                              smc_curs_diff_large(conn->rmb_desc->len,
 646                                                  &cfed, &prod);
 647        }
 648
 649        if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 650            force ||
 651            ((to_confirm > conn->rmbe_update_limit) &&
 652             ((sender_free <= (conn->rmb_desc->len / 2)) ||
 653              conn->local_rx_ctrl.prod_flags.write_blocked))) {
 654                if (conn->killed ||
 655                    conn->local_rx_ctrl.conn_state_flags.peer_conn_abort)
 656                        return;
 657                if ((smc_cdc_get_slot_and_msg_send(conn) < 0) &&
 658                    !conn->killed) {
 659                        queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work,
 660                                           SMC_TX_WORK_DELAY);
 661                        return;
 662                }
 663        }
 664        if (conn->local_rx_ctrl.prod_flags.write_blocked &&
 665            !atomic_read(&conn->bytes_to_rcv))
 666                conn->local_rx_ctrl.prod_flags.write_blocked = 0;
 667}
 668
 669/***************************** send initialize *******************************/
 670
 671/* Initialize send properties on connection establishment. NB: not __init! */
 672void smc_tx_init(struct smc_sock *smc)
 673{
 674        smc->sk.sk_write_space = smc_tx_write_space;
 675}
 676