net/smc/smc_tx.c

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