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 */ 40 static 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 */ 64 void 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 */ 74 static 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->local_tx_ctrl.conn_state_flags.peer_done_writing) { 90 rc = -EPIPE; 91 break; 92 } 93 if (smc_cdc_rxed_any_close(conn)) { 94 rc = -ECONNRESET; 95 break; 96 } 97 if (!timeo) { 98 /* ensure EPOLLOUT is subsequently generated */ 99 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 100 rc = -EAGAIN; 101 break; 102 } 103 if (signal_pending(current)) { 104 rc = sock_intr_errno(timeo); 105 break; 106 } 107 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); 108 if (atomic_read(&conn->sndbuf_space) && !conn->urg_tx_pend) 109 break; /* at least 1 byte of free & no urgent data */ 110 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 111 sk_wait_event(sk, &timeo, 112 sk->sk_err || 113 (sk->sk_shutdown & SEND_SHUTDOWN) || 114 smc_cdc_rxed_any_close(conn) || 115 (atomic_read(&conn->sndbuf_space) && 116 !conn->urg_tx_pend), 117 &wait); 118 } 119 remove_wait_queue(sk_sleep(sk), &wait); 120 return rc; 121 } 122 123 static bool smc_tx_is_corked(struct smc_sock *smc) 124 { 125 struct tcp_sock *tp = tcp_sk(smc->clcsock->sk); 126 127 return (tp->nonagle & TCP_NAGLE_CORK) ? true : false; 128 } 129 130 /* sndbuf producer: main API called by socket layer. 131 * called under sock lock. 132 */ 133 int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len) 134 { 135 size_t copylen, send_done = 0, send_remaining = len; 136 size_t chunk_len, chunk_off, chunk_len_sum; 137 struct smc_connection *conn = &smc->conn; 138 union smc_host_cursor prep; 139 struct sock *sk = &smc->sk; 140 char *sndbuf_base; 141 int tx_cnt_prep; 142 int writespace; 143 int rc, chunk; 144 145 /* This should be in poll */ 146 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); 147 148 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) { 149 rc = -EPIPE; 150 goto out_err; 151 } 152 153 while (msg_data_left(msg)) { 154 if (sk->sk_state == SMC_INIT) 155 return -ENOTCONN; 156 if (smc->sk.sk_shutdown & SEND_SHUTDOWN || 157 (smc->sk.sk_err == ECONNABORTED) || 158 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort) 159 return -EPIPE; 160 if (smc_cdc_rxed_any_close(conn)) 161 return send_done ?: -ECONNRESET; 162 163 if (msg->msg_flags & MSG_OOB) 164 conn->local_tx_ctrl.prod_flags.urg_data_pending = 1; 165 166 if (!atomic_read(&conn->sndbuf_space) || conn->urg_tx_pend) { 167 if (send_done) 168 return send_done; 169 rc = smc_tx_wait(smc, msg->msg_flags); 170 if (rc) 171 goto out_err; 172 continue; 173 } 174 175 /* initialize variables for 1st iteration of subsequent loop */ 176 /* could be just 1 byte, even after smc_tx_wait above */ 177 writespace = atomic_read(&conn->sndbuf_space); 178 /* not more than what user space asked for */ 179 copylen = min_t(size_t, send_remaining, writespace); 180 /* determine start of sndbuf */ 181 sndbuf_base = conn->sndbuf_desc->cpu_addr; 182 smc_curs_copy(&prep, &conn->tx_curs_prep, conn); 183 tx_cnt_prep = prep.count; 184 /* determine chunks where to write into sndbuf */ 185 /* either unwrapped case, or 1st chunk of wrapped case */ 186 chunk_len = min_t(size_t, copylen, conn->sndbuf_desc->len - 187 tx_cnt_prep); 188 chunk_len_sum = chunk_len; 189 chunk_off = tx_cnt_prep; 190 smc_sndbuf_sync_sg_for_cpu(conn); 191 for (chunk = 0; chunk < 2; chunk++) { 192 rc = memcpy_from_msg(sndbuf_base + chunk_off, 193 msg, chunk_len); 194 if (rc) { 195 smc_sndbuf_sync_sg_for_device(conn); 196 if (send_done) 197 return send_done; 198 goto out_err; 199 } 200 send_done += chunk_len; 201 send_remaining -= chunk_len; 202 203 if (chunk_len_sum == copylen) 204 break; /* either on 1st or 2nd iteration */ 205 /* prepare next (== 2nd) iteration */ 206 chunk_len = copylen - chunk_len; /* remainder */ 207 chunk_len_sum += chunk_len; 208 chunk_off = 0; /* modulo offset in send ring buffer */ 209 } 210 smc_sndbuf_sync_sg_for_device(conn); 211 /* update cursors */ 212 smc_curs_add(conn->sndbuf_desc->len, &prep, copylen); 213 smc_curs_copy(&conn->tx_curs_prep, &prep, conn); 214 /* increased in send tasklet smc_cdc_tx_handler() */ 215 smp_mb__before_atomic(); 216 atomic_sub(copylen, &conn->sndbuf_space); 217 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ 218 smp_mb__after_atomic(); 219 /* since we just produced more new data into sndbuf, 220 * trigger sndbuf consumer: RDMA write into peer RMBE and CDC 221 */ 222 if ((msg->msg_flags & MSG_OOB) && !send_remaining) 223 conn->urg_tx_pend = true; 224 if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) && 225 (atomic_read(&conn->sndbuf_space) > 226 (conn->sndbuf_desc->len >> 1))) 227 /* for a corked socket defer the RDMA writes if there 228 * is still sufficient sndbuf_space available 229 */ 230 schedule_delayed_work(&conn->tx_work, 231 SMC_TX_CORK_DELAY); 232 else 233 smc_tx_sndbuf_nonempty(conn); 234 } /* while (msg_data_left(msg)) */ 235 236 return send_done; 237 238 out_err: 239 rc = sk_stream_error(sk, msg->msg_flags, rc); 240 /* make sure we wake any epoll edge trigger waiter */ 241 if (unlikely(rc == -EAGAIN)) 242 sk->sk_write_space(sk); 243 return rc; 244 } 245 246 /***************************** sndbuf consumer *******************************/ 247 248 /* sndbuf consumer: actual data transfer of one target chunk with ISM write */ 249 int smcd_tx_ism_write(struct smc_connection *conn, void *data, size_t len, 250 u32 offset, int signal) 251 { 252 struct smc_ism_position pos; 253 int rc; 254 255 memset(&pos, 0, sizeof(pos)); 256 pos.token = conn->peer_token; 257 pos.index = conn->peer_rmbe_idx; 258 pos.offset = conn->tx_off + offset; 259 pos.signal = signal; 260 rc = smc_ism_write(conn->lgr->smcd, &pos, data, len); 261 if (rc) 262 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; 263 return rc; 264 } 265 266 /* sndbuf consumer: actual data transfer of one target chunk with RDMA write */ 267 static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset, 268 int num_sges, struct ib_rdma_wr *rdma_wr) 269 { 270 struct smc_link_group *lgr = conn->lgr; 271 struct smc_link *link; 272 int rc; 273 274 link = &lgr->lnk[SMC_SINGLE_LINK]; 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][SMC_SINGLE_LINK].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][SMC_SINGLE_LINK].rkey; 284 rc = ib_post_send(link->roce_qp, &rdma_wr->wr, NULL); 285 if (rc) { 286 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; 287 smc_lgr_terminate(lgr); 288 } 289 return rc; 290 } 291 292 /* sndbuf consumer */ 293 static inline void smc_tx_advance_cursors(struct smc_connection *conn, 294 union smc_host_cursor *prod, 295 union smc_host_cursor *sent, 296 size_t len) 297 { 298 smc_curs_add(conn->peer_rmbe_size, prod, len); 299 /* increased in recv tasklet smc_cdc_msg_rcv() */ 300 smp_mb__before_atomic(); 301 /* data in flight reduces usable snd_wnd */ 302 atomic_sub(len, &conn->peer_rmbe_space); 303 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */ 304 smp_mb__after_atomic(); 305 smc_curs_add(conn->sndbuf_desc->len, sent, len); 306 } 307 308 /* SMC-R helper for smc_tx_rdma_writes() */ 309 static int smcr_tx_rdma_writes(struct smc_connection *conn, size_t len, 310 size_t src_off, size_t src_len, 311 size_t dst_off, size_t dst_len, 312 struct smc_rdma_wr *wr_rdma_buf) 313 { 314 dma_addr_t dma_addr = 315 sg_dma_address(conn->sndbuf_desc->sgt[SMC_SINGLE_LINK].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() */ 360 static 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 */ 402 static 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 */ 482 static 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_rdma_wr *wr_rdma_buf; 486 struct smc_cdc_tx_pend *pend; 487 struct smc_wr_buf *wr_buf; 488 int rc; 489 490 rc = smc_cdc_get_free_slot(conn, &wr_buf, &wr_rdma_buf, &pend); 491 if (rc < 0) { 492 if (rc == -EBUSY) { 493 struct smc_sock *smc = 494 container_of(conn, struct smc_sock, conn); 495 496 if (smc->sk.sk_err == ECONNABORTED) 497 return sock_error(&smc->sk); 498 rc = 0; 499 if (conn->alert_token_local) /* connection healthy */ 500 mod_delayed_work(system_wq, &conn->tx_work, 501 SMC_TX_WORK_DELAY); 502 } 503 return rc; 504 } 505 506 spin_lock_bh(&conn->send_lock); 507 if (!pflags->urg_data_present) { 508 rc = smc_tx_rdma_writes(conn, wr_rdma_buf); 509 if (rc) { 510 smc_wr_tx_put_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], 511 (struct smc_wr_tx_pend_priv *)pend); 512 goto out_unlock; 513 } 514 } 515 516 rc = smc_cdc_msg_send(conn, wr_buf, pend); 517 if (!rc && pflags->urg_data_present) { 518 pflags->urg_data_pending = 0; 519 pflags->urg_data_present = 0; 520 } 521 522 out_unlock: 523 spin_unlock_bh(&conn->send_lock); 524 return rc; 525 } 526 527 static int smcd_tx_sndbuf_nonempty(struct smc_connection *conn) 528 { 529 struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags; 530 int rc = 0; 531 532 spin_lock_bh(&conn->send_lock); 533 if (!pflags->urg_data_present) 534 rc = smc_tx_rdma_writes(conn, NULL); 535 if (!rc) 536 rc = smcd_cdc_msg_send(conn); 537 538 if (!rc && pflags->urg_data_present) { 539 pflags->urg_data_pending = 0; 540 pflags->urg_data_present = 0; 541 } 542 spin_unlock_bh(&conn->send_lock); 543 return rc; 544 } 545 546 int smc_tx_sndbuf_nonempty(struct smc_connection *conn) 547 { 548 int rc; 549 550 if (conn->lgr->is_smcd) 551 rc = smcd_tx_sndbuf_nonempty(conn); 552 else 553 rc = smcr_tx_sndbuf_nonempty(conn); 554 555 if (!rc) { 556 /* trigger socket release if connection is closing */ 557 struct smc_sock *smc = container_of(conn, struct smc_sock, 558 conn); 559 smc_close_wake_tx_prepared(smc); 560 } 561 return rc; 562 } 563 564 /* Wakeup sndbuf consumers from process context 565 * since there is more data to transmit 566 */ 567 void smc_tx_work(struct work_struct *work) 568 { 569 struct smc_connection *conn = container_of(to_delayed_work(work), 570 struct smc_connection, 571 tx_work); 572 struct smc_sock *smc = container_of(conn, struct smc_sock, conn); 573 int rc; 574 575 lock_sock(&smc->sk); 576 if (smc->sk.sk_err || 577 !conn->alert_token_local || 578 conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) 579 goto out; 580 581 rc = smc_tx_sndbuf_nonempty(conn); 582 if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked && 583 !atomic_read(&conn->bytes_to_rcv)) 584 conn->local_rx_ctrl.prod_flags.write_blocked = 0; 585 586 out: 587 release_sock(&smc->sk); 588 } 589 590 void smc_tx_consumer_update(struct smc_connection *conn, bool force) 591 { 592 union smc_host_cursor cfed, cons, prod; 593 int sender_free = conn->rmb_desc->len; 594 int to_confirm; 595 596 smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); 597 smc_curs_copy(&cfed, &conn->rx_curs_confirmed, conn); 598 to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons); 599 if (to_confirm > conn->rmbe_update_limit) { 600 smc_curs_copy(&prod, &conn->local_rx_ctrl.prod, conn); 601 sender_free = conn->rmb_desc->len - 602 smc_curs_diff_large(conn->rmb_desc->len, 603 &cfed, &prod); 604 } 605 606 if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || 607 force || 608 ((to_confirm > conn->rmbe_update_limit) && 609 ((sender_free <= (conn->rmb_desc->len / 2)) || 610 conn->local_rx_ctrl.prod_flags.write_blocked))) { 611 if ((smc_cdc_get_slot_and_msg_send(conn) < 0) && 612 conn->alert_token_local) { /* connection healthy */ 613 schedule_delayed_work(&conn->tx_work, 614 SMC_TX_WORK_DELAY); 615 return; 616 } 617 } 618 if (conn->local_rx_ctrl.prod_flags.write_blocked && 619 !atomic_read(&conn->bytes_to_rcv)) 620 conn->local_rx_ctrl.prod_flags.write_blocked = 0; 621 } 622 623 /***************************** send initialize *******************************/ 624 625 /* Initialize send properties on connection establishment. NB: not __init! */ 626 void smc_tx_init(struct smc_sock *smc) 627 { 628 smc->sk.sk_write_space = smc_tx_write_space; 629 } 630