// SPDX-License-Identifier: GPL-2.0 /* * Shared Memory Communications over RDMA (SMC-R) and RoCE * * Manage send buffer. * Producer: * Copy user space data into send buffer, if send buffer space available. * Consumer: * Trigger RDMA write into RMBE of peer and send CDC, if RMBE space available. * * Copyright IBM Corp. 2016 * * Author(s): Ursula Braun */ #include #include #include #include #include #include #include "smc.h" #include "smc_wr.h" #include "smc_cdc.h" #include "smc_close.h" #include "smc_ism.h" #include "smc_tx.h" #include "smc_stats.h" #include "smc_tracepoint.h" #define SMC_TX_WORK_DELAY 0 /***************************** sndbuf producer *******************************/ /* callback implementation for sk.sk_write_space() * to wakeup sndbuf producers that blocked with smc_tx_wait(). * called under sk_socket lock. */ static void smc_tx_write_space(struct sock *sk) { struct socket *sock = sk->sk_socket; struct smc_sock *smc = smc_sk(sk); struct socket_wq *wq; /* similar to sk_stream_write_space */ if (atomic_read(&smc->conn.sndbuf_space) && sock) { if (test_bit(SOCK_NOSPACE, &sock->flags)) SMC_STAT_RMB_TX_FULL(smc, !smc->conn.lnk); clear_bit(SOCK_NOSPACE, &sock->flags); rcu_read_lock(); wq = rcu_dereference(sk->sk_wq); if (skwq_has_sleeper(wq)) wake_up_interruptible_poll(&wq->wait, EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN)) sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT); rcu_read_unlock(); } } /* Wakeup sndbuf producers that blocked with smc_tx_wait(). * Cf. tcp_data_snd_check()=>tcp_check_space()=>tcp_new_space(). */ void smc_tx_sndbuf_nonfull(struct smc_sock *smc) { if (smc->sk.sk_socket && test_bit(SOCK_NOSPACE, &smc->sk.sk_socket->flags)) smc->sk.sk_write_space(&smc->sk); } /* blocks sndbuf producer until at least one byte of free space available * or urgent Byte was consumed */ static int smc_tx_wait(struct smc_sock *smc, int flags) { DEFINE_WAIT_FUNC(wait, woken_wake_function); struct smc_connection *conn = &smc->conn; struct sock *sk = &smc->sk; long timeo; int rc = 0; /* similar to sk_stream_wait_memory */ timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); add_wait_queue(sk_sleep(sk), &wait); while (1) { sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk); if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN) || conn->killed || conn->local_tx_ctrl.conn_state_flags.peer_done_writing) { rc = -EPIPE; break; } if (smc_cdc_rxed_any_close(conn)) { rc = -ECONNRESET; break; } if (!timeo) { /* ensure EPOLLOUT is subsequently generated */ set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); rc = -EAGAIN; break; } if (signal_pending(current)) { rc = sock_intr_errno(timeo); break; } sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); if (atomic_read(&conn->sndbuf_space) && !conn->urg_tx_pend) break; /* at least 1 byte of free & no urgent data */ set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); sk_wait_event(sk, &timeo, sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN) || smc_cdc_rxed_any_close(conn) || (atomic_read(&conn->sndbuf_space) && !conn->urg_tx_pend), &wait); } remove_wait_queue(sk_sleep(sk), &wait); return rc; } static bool smc_tx_is_corked(struct smc_sock *smc) { struct tcp_sock *tp = tcp_sk(smc->clcsock->sk); return (tp->nonagle & TCP_NAGLE_CORK) ? true : false; } /* sndbuf producer: main API called by socket layer. * called under sock lock. */ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len) { size_t copylen, send_done = 0, send_remaining = len; size_t chunk_len, chunk_off, chunk_len_sum; struct smc_connection *conn = &smc->conn; union smc_host_cursor prep; struct sock *sk = &smc->sk; char *sndbuf_base; int tx_cnt_prep; int writespace; int rc, chunk; /* This should be in poll */ sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) { rc = -EPIPE; goto out_err; } if (sk->sk_state == SMC_INIT) return -ENOTCONN; if (len > conn->sndbuf_desc->len) SMC_STAT_RMB_TX_SIZE_SMALL(smc, !conn->lnk); if (len > conn->peer_rmbe_size) SMC_STAT_RMB_TX_PEER_SIZE_SMALL(smc, !conn->lnk); if (msg->msg_flags & MSG_OOB) SMC_STAT_INC(smc, urg_data_cnt); while (msg_data_left(msg)) { if (smc->sk.sk_shutdown & SEND_SHUTDOWN || (smc->sk.sk_err == ECONNABORTED) || conn->killed) return -EPIPE; if (smc_cdc_rxed_any_close(conn)) return send_done ?: -ECONNRESET; if (msg->msg_flags & MSG_OOB) conn->local_tx_ctrl.prod_flags.urg_data_pending = 1; if (!atomic_read(&conn->sndbuf_space) || conn->urg_tx_pend) { if (send_done) return send_done; rc = smc_tx_wait(smc, msg->msg_flags); if (rc) goto out_err; continue; } /* initialize variables for 1st iteration of subsequent loop */ /* could be just 1 byte, even after smc_tx_wait above */ writespace = atomic_read(&conn->sndbuf_space); /* not more than what user space asked for */ copylen = min_t(size_t, send_remaining, writespace); /* determine start of sndbuf */ sndbuf_base = conn->sndbuf_desc->cpu_addr; smc_curs_copy(&prep, &conn->tx_curs_prep, conn); tx_cnt_prep = prep.count; /* determine chunks where to write into sndbuf */ /* either unwrapped case, or 1st chunk of wrapped case */ chunk_len = min_t(size_t, copylen, conn->sndbuf_desc->len - tx_cnt_prep); chunk_len_sum = chunk_len; chunk_off = tx_cnt_prep; smc_sndbuf_sync_sg_for_cpu(conn); for (chunk = 0; chunk < 2; chunk++) { rc = memcpy_from_msg(sndbuf_base + chunk_off, msg, chunk_len); if (rc) { smc_sndbuf_sync_sg_for_device(conn); if (send_done) return send_done; goto out_err; } send_done += chunk_len; send_remaining -= chunk_len; if (chunk_len_sum == copylen) break; /* either on 1st or 2nd iteration */ /* prepare next (== 2nd) iteration */ chunk_len = copylen - chunk_len; /* remainder */ chunk_len_sum += chunk_len; chunk_off = 0; /* modulo offset in send ring buffer */ } smc_sndbuf_sync_sg_for_device(conn); /* update cursors */ smc_curs_add(conn->sndbuf_desc->len, &prep, copylen); smc_curs_copy(&conn->tx_curs_prep, &prep, conn); /* increased in send tasklet smc_cdc_tx_handler() */ smp_mb__before_atomic(); atomic_sub(copylen, &conn->sndbuf_space); /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ smp_mb__after_atomic(); /* since we just produced more new data into sndbuf, * trigger sndbuf consumer: RDMA write into peer RMBE and CDC */ if ((msg->msg_flags & MSG_OOB) && !send_remaining) conn->urg_tx_pend = true; if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) && (atomic_read(&conn->sndbuf_space))) /* for a corked socket defer the RDMA writes if * sndbuf_space is still available. The applications * should known how/when to uncork it. */ continue; smc_tx_sndbuf_nonempty(conn); trace_smc_tx_sendmsg(smc, copylen); } /* while (msg_data_left(msg)) */ return send_done; out_err: rc = sk_stream_error(sk, msg->msg_flags, rc); /* make sure we wake any epoll edge trigger waiter */ if (unlikely(rc == -EAGAIN)) sk->sk_write_space(sk); return rc; } /***************************** sndbuf consumer *******************************/ /* sndbuf consumer: actual data transfer of one target chunk with ISM write */ int smcd_tx_ism_write(struct smc_connection *conn, void *data, size_t len, u32 offset, int signal) { struct smc_ism_position pos; int rc; memset(&pos, 0, sizeof(pos)); pos.token = conn->peer_token; pos.index = conn->peer_rmbe_idx; pos.offset = conn->tx_off + offset; pos.signal = signal; rc = smc_ism_write(conn->lgr->smcd, &pos, data, len); if (rc) conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; return rc; } /* sndbuf consumer: actual data transfer of one target chunk with RDMA write */ static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset, int num_sges, struct ib_rdma_wr *rdma_wr) { struct smc_link_group *lgr = conn->lgr; struct smc_link *link = conn->lnk; int rc; rdma_wr->wr.wr_id = smc_wr_tx_get_next_wr_id(link); rdma_wr->wr.num_sge = num_sges; rdma_wr->remote_addr = lgr->rtokens[conn->rtoken_idx][link->link_idx].dma_addr + /* RMBE within RMB */ conn->tx_off + /* offset within RMBE */ peer_rmbe_offset; rdma_wr->rkey = lgr->rtokens[conn->rtoken_idx][link->link_idx].rkey; rc = ib_post_send(link->roce_qp, &rdma_wr->wr, NULL); if (rc) smcr_link_down_cond_sched(link); return rc; } /* sndbuf consumer */ static inline void smc_tx_advance_cursors(struct smc_connection *conn, union smc_host_cursor *prod, union smc_host_cursor *sent, size_t len) { smc_curs_add(conn->peer_rmbe_size, prod, len); /* increased in recv tasklet smc_cdc_msg_rcv() */ smp_mb__before_atomic(); /* data in flight reduces usable snd_wnd */ atomic_sub(len, &conn->peer_rmbe_space); /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */ smp_mb__after_atomic(); smc_curs_add(conn->sndbuf_desc->len, sent, len); } /* SMC-R helper for smc_tx_rdma_writes() */ static int smcr_tx_rdma_writes(struct smc_connection *conn, size_t len, size_t src_off, size_t src_len, size_t dst_off, size_t dst_len, struct smc_rdma_wr *wr_rdma_buf) { struct smc_link *link = conn->lnk; dma_addr_t dma_addr = sg_dma_address(conn->sndbuf_desc->sgt[link->link_idx].sgl); int src_len_sum = src_len, dst_len_sum = dst_len; int sent_count = src_off; int srcchunk, dstchunk; int num_sges; int rc; for (dstchunk = 0; dstchunk < 2; dstchunk++) { struct ib_sge *sge = wr_rdma_buf->wr_tx_rdma[dstchunk].wr.sg_list; num_sges = 0; for (srcchunk = 0; srcchunk < 2; srcchunk++) { sge[srcchunk].addr = dma_addr + src_off; sge[srcchunk].length = src_len; num_sges++; src_off += src_len; if (src_off >= conn->sndbuf_desc->len) src_off -= conn->sndbuf_desc->len; /* modulo in send ring */ if (src_len_sum == dst_len) break; /* either on 1st or 2nd iteration */ /* prepare next (== 2nd) iteration */ src_len = dst_len - src_len; /* remainder */ src_len_sum += src_len; } rc = smc_tx_rdma_write(conn, dst_off, num_sges, &wr_rdma_buf->wr_tx_rdma[dstchunk]); if (rc) return rc; if (dst_len_sum == len) break; /* either on 1st or 2nd iteration */ /* prepare next (== 2nd) iteration */ dst_off = 0; /* modulo offset in RMBE ring buffer */ dst_len = len - dst_len; /* remainder */ dst_len_sum += dst_len; src_len = min_t(int, dst_len, conn->sndbuf_desc->len - sent_count); src_len_sum = src_len; } return 0; } /* SMC-D helper for smc_tx_rdma_writes() */ static int smcd_tx_rdma_writes(struct smc_connection *conn, size_t len, size_t src_off, size_t src_len, size_t dst_off, size_t dst_len) { int src_len_sum = src_len, dst_len_sum = dst_len; int srcchunk, dstchunk; int rc; for (dstchunk = 0; dstchunk < 2; dstchunk++) { for (srcchunk = 0; srcchunk < 2; srcchunk++) { void *data = conn->sndbuf_desc->cpu_addr + src_off; rc = smcd_tx_ism_write(conn, data, src_len, dst_off + sizeof(struct smcd_cdc_msg), 0); if (rc) return rc; dst_off += src_len; src_off += src_len; if (src_off >= conn->sndbuf_desc->len) src_off -= conn->sndbuf_desc->len; /* modulo in send ring */ if (src_len_sum == dst_len) break; /* either on 1st or 2nd iteration */ /* prepare next (== 2nd) iteration */ src_len = dst_len - src_len; /* remainder */ src_len_sum += src_len; } if (dst_len_sum == len) break; /* either on 1st or 2nd iteration */ /* prepare next (== 2nd) iteration */ dst_off = 0; /* modulo offset in RMBE ring buffer */ dst_len = len - dst_len; /* remainder */ dst_len_sum += dst_len; src_len = min_t(int, dst_len, conn->sndbuf_desc->len - src_off); src_len_sum = src_len; } return 0; } /* sndbuf consumer: prepare all necessary (src&dst) chunks of data transmit; * usable snd_wnd as max transmit */ static int smc_tx_rdma_writes(struct smc_connection *conn, struct smc_rdma_wr *wr_rdma_buf) { size_t len, src_len, dst_off, dst_len; /* current chunk values */ union smc_host_cursor sent, prep, prod, cons; struct smc_cdc_producer_flags *pflags; int to_send, rmbespace; int rc; /* source: sndbuf */ smc_curs_copy(&sent, &conn->tx_curs_sent, conn); smc_curs_copy(&prep, &conn->tx_curs_prep, conn); /* cf. wmem_alloc - (snd_max - snd_una) */ to_send = smc_curs_diff(conn->sndbuf_desc->len, &sent, &prep); if (to_send <= 0) return 0; /* destination: RMBE */ /* cf. snd_wnd */ rmbespace = atomic_read(&conn->peer_rmbe_space); if (rmbespace <= 0) { struct smc_sock *smc = container_of(conn, struct smc_sock, conn); SMC_STAT_RMB_TX_PEER_FULL(smc, !conn->lnk); return 0; } smc_curs_copy(&prod, &conn->local_tx_ctrl.prod, conn); smc_curs_copy(&cons, &conn->local_rx_ctrl.cons, conn); /* if usable snd_wnd closes ask peer to advertise once it opens again */ pflags = &conn->local_tx_ctrl.prod_flags; pflags->write_blocked = (to_send >= rmbespace); /* cf. usable snd_wnd */ len = min(to_send, rmbespace); /* initialize variables for first iteration of subsequent nested loop */ dst_off = prod.count; if (prod.wrap == cons.wrap) { /* the filled destination area is unwrapped, * hence the available free destination space is wrapped * and we need 2 destination chunks of sum len; start with 1st * which is limited by what's available in sndbuf */ dst_len = min_t(size_t, conn->peer_rmbe_size - prod.count, len); } else { /* the filled destination area is wrapped, * hence the available free destination space is unwrapped * and we need a single destination chunk of entire len */ dst_len = len; } /* dst_len determines the maximum src_len */ if (sent.count + dst_len <= conn->sndbuf_desc->len) { /* unwrapped src case: single chunk of entire dst_len */ src_len = dst_len; } else { /* wrapped src case: 2 chunks of sum dst_len; start with 1st: */ src_len = conn->sndbuf_desc->len - sent.count; } if (conn->lgr->is_smcd) rc = smcd_tx_rdma_writes(conn, len, sent.count, src_len, dst_off, dst_len); else rc = smcr_tx_rdma_writes(conn, len, sent.count, src_len, dst_off, dst_len, wr_rdma_buf); if (rc) return rc; if (conn->urg_tx_pend && len == to_send) pflags->urg_data_present = 1; smc_tx_advance_cursors(conn, &prod, &sent, len); /* update connection's cursors with advanced local cursors */ smc_curs_copy(&conn->local_tx_ctrl.prod, &prod, conn); /* dst: peer RMBE */ smc_curs_copy(&conn->tx_curs_sent, &sent, conn);/* src: local sndbuf */ return 0; } /* Wakeup sndbuf consumers from any context (IRQ or process) * since there is more data to transmit; usable snd_wnd as max transmit */ static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn) { struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags; struct smc_link *link = conn->lnk; struct smc_rdma_wr *wr_rdma_buf; struct smc_cdc_tx_pend *pend; struct smc_wr_buf *wr_buf; int rc; if (!link || !smc_wr_tx_link_hold(link)) return -ENOLINK; rc = smc_cdc_get_free_slot(conn, link, &wr_buf, &wr_rdma_buf, &pend); if (rc < 0) { smc_wr_tx_link_put(link); if (rc == -EBUSY) { struct smc_sock *smc = container_of(conn, struct smc_sock, conn); if (smc->sk.sk_err == ECONNABORTED) return sock_error(&smc->sk); if (conn->killed) return -EPIPE; rc = 0; mod_delayed_work(conn->lgr->tx_wq, &conn->tx_work, SMC_TX_WORK_DELAY); } return rc; } spin_lock_bh(&conn->send_lock); if (link != conn->lnk) { /* link of connection changed, tx_work will restart */ smc_wr_tx_put_slot(link, (struct smc_wr_tx_pend_priv *)pend); rc = -ENOLINK; goto out_unlock; } if (!pflags->urg_data_present) { rc = smc_tx_rdma_writes(conn, wr_rdma_buf); if (rc) { smc_wr_tx_put_slot(link, (struct smc_wr_tx_pend_priv *)pend); goto out_unlock; } } rc = smc_cdc_msg_send(conn, wr_buf, pend); if (!rc && pflags->urg_data_present) { pflags->urg_data_pending = 0; pflags->urg_data_present = 0; } out_unlock: spin_unlock_bh(&conn->send_lock); smc_wr_tx_link_put(link); return rc; } static int smcd_tx_sndbuf_nonempty(struct smc_connection *conn) { struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags; int rc = 0; spin_lock_bh(&conn->send_lock); if (!pflags->urg_data_present) rc = smc_tx_rdma_writes(conn, NULL); if (!rc) rc = smcd_cdc_msg_send(conn); if (!rc && pflags->urg_data_present) { pflags->urg_data_pending = 0; pflags->urg_data_present = 0; } spin_unlock_bh(&conn->send_lock); return rc; } int smc_tx_sndbuf_nonempty(struct smc_connection *conn) { int rc; if (conn->killed || conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) return -EPIPE; /* connection being aborted */ if (conn->lgr->is_smcd) rc = smcd_tx_sndbuf_nonempty(conn); else rc = smcr_tx_sndbuf_nonempty(conn); if (!rc) { /* trigger socket release if connection is closing */ struct smc_sock *smc = container_of(conn, struct smc_sock, conn); smc_close_wake_tx_prepared(smc); } return rc; } void smc_tx_pending(struct smc_connection *conn) { struct smc_sock *smc = container_of(conn, struct smc_sock, conn); int rc; if (smc->sk.sk_err) return; rc = smc_tx_sndbuf_nonempty(conn); if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked && !atomic_read(&conn->bytes_to_rcv)) conn->local_rx_ctrl.prod_flags.write_blocked = 0; } /* Wakeup sndbuf consumers from process context * since there is more data to transmit */ void smc_tx_work(struct work_struct *work) { struct smc_connection *conn = container_of(to_delayed_work(work), struct smc_connection, tx_work); struct smc_sock *smc = container_of(conn, struct smc_sock, conn); lock_sock(&smc->sk); smc_tx_pending(conn); release_sock(&smc->sk); } void smc_tx_consumer_update(struct smc_connection *conn, bool force) { union smc_host_cursor cfed, cons, prod; int sender_free = conn->rmb_desc->len; int to_confirm; smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); smc_curs_copy(&cfed, &conn->rx_curs_confirmed, conn); to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons); if (to_confirm > conn->rmbe_update_limit) { smc_curs_copy(&prod, &conn->local_rx_ctrl.prod, conn); sender_free = conn->rmb_desc->len - smc_curs_diff_large(conn->rmb_desc->len, &cfed, &prod); } if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || force || ((to_confirm > conn->rmbe_update_limit) && ((sender_free <= (conn->rmb_desc->len / 2)) || conn->local_rx_ctrl.prod_flags.write_blocked))) { if (conn->killed || conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) return; if ((smc_cdc_get_slot_and_msg_send(conn) < 0) && !conn->killed) { queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work, SMC_TX_WORK_DELAY); return; } } if (conn->local_rx_ctrl.prod_flags.write_blocked && !atomic_read(&conn->bytes_to_rcv)) conn->local_rx_ctrl.prod_flags.write_blocked = 0; } /***************************** send initialize *******************************/ /* Initialize send properties on connection establishment. NB: not __init! */ void smc_tx_init(struct smc_sock *smc) { smc->sk.sk_write_space = smc_tx_write_space; }