| // 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 <ubraun@linux.vnet.ibm.com> |
| */ |
| |
| #include <linux/net.h> |
| #include <linux/rcupdate.h> |
| #include <linux/workqueue.h> |
| #include <linux/sched/signal.h> |
| |
| #include <net/sock.h> |
| #include <net/tcp.h> |
| |
| #include "smc.h" |
| #include "smc_wr.h" |
| #include "smc_cdc.h" |
| #include "smc_tx.h" |
| |
| #define SMC_TX_WORK_DELAY HZ |
| #define SMC_TX_CORK_DELAY (HZ >> 2) /* 250 ms */ |
| |
| /***************************** 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) { |
| 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; |
| bool noblock; |
| long timeo; |
| int rc = 0; |
| |
| /* similar to sk_stream_wait_memory */ |
| timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); |
| noblock = timeo ? false : true; |
| 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->local_tx_ctrl.conn_state_flags.peer_done_writing) { |
| rc = -EPIPE; |
| break; |
| } |
| if (smc_cdc_rxed_any_close(conn)) { |
| rc = -ECONNRESET; |
| break; |
| } |
| if (!timeo) { |
| if (noblock) |
| 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; |
| } |
| |
| while (msg_data_left(msg)) { |
| if (sk->sk_state == SMC_INIT) |
| return -ENOTCONN; |
| if (smc->sk.sk_shutdown & SEND_SHUTDOWN || |
| (smc->sk.sk_err == ECONNABORTED) || |
| conn->local_tx_ctrl.conn_state_flags.peer_conn_abort) |
| 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) { |
| rc = smc_tx_wait(smc, msg->msg_flags); |
| if (rc) { |
| if (send_done) |
| return send_done; |
| 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_write(&prep, |
| smc_curs_read(&conn->tx_curs_prep, conn), |
| 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_write(&conn->tx_curs_prep, |
| smc_curs_read(&prep, conn), |
| 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) > |
| (conn->sndbuf_desc->len >> 1))) |
| /* for a corked socket defer the RDMA writes if there |
| * is still sufficient sndbuf_space available |
| */ |
| schedule_delayed_work(&conn->tx_work, |
| SMC_TX_CORK_DELAY); |
| else |
| smc_tx_sndbuf_nonempty(conn); |
| } /* 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 RDMA write */ |
| static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset, |
| int num_sges, struct ib_sge sges[]) |
| { |
| struct smc_link_group *lgr = conn->lgr; |
| struct ib_send_wr *failed_wr = NULL; |
| struct ib_rdma_wr rdma_wr; |
| struct smc_link *link; |
| int rc; |
| |
| memset(&rdma_wr, 0, sizeof(rdma_wr)); |
| link = &lgr->lnk[SMC_SINGLE_LINK]; |
| rdma_wr.wr.wr_id = smc_wr_tx_get_next_wr_id(link); |
| rdma_wr.wr.sg_list = sges; |
| rdma_wr.wr.num_sge = num_sges; |
| rdma_wr.wr.opcode = IB_WR_RDMA_WRITE; |
| rdma_wr.remote_addr = |
| lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].dma_addr + |
| /* RMBE within RMB */ |
| conn->tx_off + |
| /* offset within RMBE */ |
| peer_rmbe_offset; |
| rdma_wr.rkey = lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].rkey; |
| rc = ib_post_send(link->roce_qp, &rdma_wr.wr, &failed_wr); |
| if (rc) { |
| conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; |
| smc_lgr_terminate(lgr); |
| } |
| 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); |
| } |
| |
| /* 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) |
| { |
| size_t src_off, src_len, dst_off, dst_len; /* current chunk values */ |
| size_t len, dst_len_sum, src_len_sum, dstchunk, srcchunk; |
| union smc_host_cursor sent, prep, prod, cons; |
| struct ib_sge sges[SMC_IB_MAX_SEND_SGE]; |
| struct smc_link_group *lgr = conn->lgr; |
| struct smc_cdc_producer_flags *pflags; |
| int to_send, rmbespace; |
| struct smc_link *link; |
| dma_addr_t dma_addr; |
| int num_sges; |
| int rc; |
| |
| /* source: sndbuf */ |
| smc_curs_write(&sent, smc_curs_read(&conn->tx_curs_sent, conn), conn); |
| smc_curs_write(&prep, smc_curs_read(&conn->tx_curs_prep, conn), 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) |
| return 0; |
| smc_curs_write(&prod, |
| smc_curs_read(&conn->local_tx_ctrl.prod, conn), |
| conn); |
| smc_curs_write(&cons, |
| smc_curs_read(&conn->local_rx_ctrl.cons, conn), |
| 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 */ |
| link = &lgr->lnk[SMC_SINGLE_LINK]; |
| 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_sum = dst_len; |
| src_off = sent.count; |
| /* 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; |
| } |
| src_len_sum = src_len; |
| dma_addr = sg_dma_address(conn->sndbuf_desc->sgt[SMC_SINGLE_LINK].sgl); |
| for (dstchunk = 0; dstchunk < 2; dstchunk++) { |
| num_sges = 0; |
| for (srcchunk = 0; srcchunk < 2; srcchunk++) { |
| sges[srcchunk].addr = dma_addr + src_off; |
| sges[srcchunk].length = src_len; |
| sges[srcchunk].lkey = link->roce_pd->local_dma_lkey; |
| 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, sges); |
| 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; |
| } |
| |
| 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_write(&conn->local_tx_ctrl.prod, |
| smc_curs_read(&prod, conn), |
| conn); |
| /* dst: peer RMBE */ |
| smc_curs_write(&conn->tx_curs_sent, |
| smc_curs_read(&sent, conn), |
| 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 |
| */ |
| int smc_tx_sndbuf_nonempty(struct smc_connection *conn) |
| { |
| struct smc_cdc_producer_flags *pflags; |
| struct smc_cdc_tx_pend *pend; |
| struct smc_wr_buf *wr_buf; |
| int rc; |
| |
| spin_lock_bh(&conn->send_lock); |
| rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend); |
| if (rc < 0) { |
| if (rc == -EBUSY) { |
| struct smc_sock *smc = |
| container_of(conn, struct smc_sock, conn); |
| |
| if (smc->sk.sk_err == ECONNABORTED) { |
| rc = sock_error(&smc->sk); |
| goto out_unlock; |
| } |
| rc = 0; |
| if (conn->alert_token_local) /* connection healthy */ |
| mod_delayed_work(system_wq, &conn->tx_work, |
| SMC_TX_WORK_DELAY); |
| } |
| goto out_unlock; |
| } |
| |
| if (!conn->local_tx_ctrl.prod_flags.urg_data_present) { |
| rc = smc_tx_rdma_writes(conn); |
| if (rc) { |
| smc_wr_tx_put_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], |
| (struct smc_wr_tx_pend_priv *)pend); |
| goto out_unlock; |
| } |
| } |
| |
| rc = smc_cdc_msg_send(conn, wr_buf, pend); |
| pflags = &conn->local_tx_ctrl.prod_flags; |
| if (!rc && pflags->urg_data_present) { |
| pflags->urg_data_pending = 0; |
| pflags->urg_data_present = 0; |
| } |
| |
| out_unlock: |
| spin_unlock_bh(&conn->send_lock); |
| return rc; |
| } |
| |
| /* 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); |
| int rc; |
| |
| lock_sock(&smc->sk); |
| if (smc->sk.sk_err || |
| !conn->alert_token_local || |
| conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) |
| goto out; |
| |
| 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; |
| |
| out: |
| release_sock(&smc->sk); |
| } |
| |
| void smc_tx_consumer_update(struct smc_connection *conn, bool force) |
| { |
| union smc_host_cursor cfed, cons; |
| int to_confirm; |
| |
| smc_curs_write(&cons, |
| smc_curs_read(&conn->local_tx_ctrl.cons, conn), |
| conn); |
| smc_curs_write(&cfed, |
| smc_curs_read(&conn->rx_curs_confirmed, conn), |
| conn); |
| to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons); |
| |
| if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || |
| force || |
| ((to_confirm > conn->rmbe_update_limit) && |
| ((to_confirm > (conn->rmb_desc->len / 2)) || |
| conn->local_rx_ctrl.prod_flags.write_blocked))) { |
| if ((smc_cdc_get_slot_and_msg_send(conn) < 0) && |
| conn->alert_token_local) { /* connection healthy */ |
| schedule_delayed_work(&conn->tx_work, |
| SMC_TX_WORK_DELAY); |
| return; |
| } |
| smc_curs_write(&conn->rx_curs_confirmed, |
| smc_curs_read(&conn->local_tx_ctrl.cons, conn), |
| conn); |
| conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0; |
| } |
| 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; |
| } |