// SPDX-License-Identifier: GPL-2.0 /* * Shared Memory Communications over RDMA (SMC-R) and RoCE * * Connection Data Control (CDC) * handles flow control * * Copyright IBM Corp. 2016 * * Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com> */ #include <linux/spinlock.h> #include "smc.h" #include "smc_wr.h" #include "smc_cdc.h" #include "smc_tx.h" #include "smc_rx.h" #include "smc_close.h" /********************************** send *************************************/ /* handler for send/transmission completion of a CDC msg */ static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd, struct smc_link *link, enum ib_wc_status wc_status) { struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd; struct smc_connection *conn = cdcpend->conn; struct smc_sock *smc; int diff; if (!conn) /* already dismissed */ return; smc = container_of(conn, struct smc_sock, conn); bh_lock_sock(&smc->sk); if (!wc_status) { diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len, &cdcpend->conn->tx_curs_fin, &cdcpend->cursor); /* sndbuf_space is decreased in smc_sendmsg */ smp_mb__before_atomic(); atomic_add(diff, &cdcpend->conn->sndbuf_space); /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ smp_mb__after_atomic(); smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn); smc_curs_copy(&conn->local_tx_ctrl_fin, &cdcpend->p_cursor, conn); conn->tx_cdc_seq_fin = cdcpend->ctrl_seq; } smc_tx_sndbuf_nonfull(smc); bh_unlock_sock(&smc->sk); } int smc_cdc_get_free_slot(struct smc_connection *conn, struct smc_link *link, struct smc_wr_buf **wr_buf, struct smc_rdma_wr **wr_rdma_buf, struct smc_cdc_tx_pend **pend) { int rc; rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf, wr_rdma_buf, (struct smc_wr_tx_pend_priv **)pend); if (conn->killed) { /* abnormal termination */ if (!rc) smc_wr_tx_put_slot(link, (struct smc_wr_tx_pend_priv *)pend); rc = -EPIPE; } return rc; } static inline void smc_cdc_add_pending_send(struct smc_connection *conn, struct smc_cdc_tx_pend *pend) { BUILD_BUG_ON_MSG( sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE, "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)"); BUILD_BUG_ON_MSG( offsetofend(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE, "must adapt SMC_WR_TX_SIZE to sizeof(struct smc_cdc_msg); if not all smc_wr upper layer protocols use the same message size any more, must start to set link->wr_tx_sges[i].length on each individual smc_wr_tx_send()"); BUILD_BUG_ON_MSG( sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE, "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)"); pend->conn = conn; pend->cursor = conn->tx_curs_sent; pend->p_cursor = conn->local_tx_ctrl.prod; pend->ctrl_seq = conn->tx_cdc_seq; } int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf, struct smc_cdc_tx_pend *pend) { struct smc_link *link = conn->lnk; union smc_host_cursor cfed; int rc; smc_cdc_add_pending_send(conn, pend); conn->tx_cdc_seq++; conn->local_tx_ctrl.seqno = conn->tx_cdc_seq; smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed); rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend); if (!rc) { smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn); conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0; } else { conn->tx_cdc_seq--; conn->local_tx_ctrl.seqno = conn->tx_cdc_seq; } return rc; } /* send a validation msg indicating the move of a conn to an other QP link */ int smcr_cdc_msg_send_validation(struct smc_connection *conn, struct smc_cdc_tx_pend *pend, struct smc_wr_buf *wr_buf) { struct smc_host_cdc_msg *local = &conn->local_tx_ctrl; struct smc_link *link = conn->lnk; struct smc_cdc_msg *peer; int rc; peer = (struct smc_cdc_msg *)wr_buf; peer->common.type = local->common.type; peer->len = local->len; peer->seqno = htons(conn->tx_cdc_seq_fin); /* seqno last compl. tx */ peer->token = htonl(local->token); peer->prod_flags.failover_validation = 1; rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend); return rc; } static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn) { struct smc_cdc_tx_pend *pend; struct smc_wr_buf *wr_buf; struct smc_link *link; bool again = false; int rc; again: link = conn->lnk; if (!smc_wr_tx_link_hold(link)) return -ENOLINK; rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend); if (rc) goto put_out; spin_lock_bh(&conn->send_lock); if (link != conn->lnk) { /* link of connection changed, try again one time*/ spin_unlock_bh(&conn->send_lock); smc_wr_tx_put_slot(link, (struct smc_wr_tx_pend_priv *)pend); smc_wr_tx_link_put(link); if (again) return -ENOLINK; again = true; goto again; } rc = smc_cdc_msg_send(conn, wr_buf, pend); spin_unlock_bh(&conn->send_lock); put_out: smc_wr_tx_link_put(link); return rc; } int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn) { int rc; if (!conn->lgr || (conn->lgr->is_smcd && conn->lgr->peer_shutdown)) return -EPIPE; if (conn->lgr->is_smcd) { spin_lock_bh(&conn->send_lock); rc = smcd_cdc_msg_send(conn); spin_unlock_bh(&conn->send_lock); } else { rc = smcr_cdc_get_slot_and_msg_send(conn); } return rc; } static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend, unsigned long data) { struct smc_connection *conn = (struct smc_connection *)data; struct smc_cdc_tx_pend *cdc_pend = (struct smc_cdc_tx_pend *)tx_pend; return cdc_pend->conn == conn; } static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend) { struct smc_cdc_tx_pend *cdc_pend = (struct smc_cdc_tx_pend *)tx_pend; cdc_pend->conn = NULL; } void smc_cdc_tx_dismiss_slots(struct smc_connection *conn) { struct smc_link *link = conn->lnk; smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE, smc_cdc_tx_filter, smc_cdc_tx_dismisser, (unsigned long)conn); } /* Send a SMC-D CDC header. * This increments the free space available in our send buffer. * Also update the confirmed receive buffer with what was sent to the peer. */ int smcd_cdc_msg_send(struct smc_connection *conn) { struct smc_sock *smc = container_of(conn, struct smc_sock, conn); union smc_host_cursor curs; struct smcd_cdc_msg cdc; int rc, diff; memset(&cdc, 0, sizeof(cdc)); cdc.common.type = SMC_CDC_MSG_TYPE; curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs); cdc.prod.wrap = curs.wrap; cdc.prod.count = curs.count; curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs); cdc.cons.wrap = curs.wrap; cdc.cons.count = curs.count; cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags; cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags; rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1); if (rc) return rc; smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn); conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0; /* Calculate transmitted data and increment free send buffer space */ diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin, &conn->tx_curs_sent); /* increased by confirmed number of bytes */ smp_mb__before_atomic(); atomic_add(diff, &conn->sndbuf_space); /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ smp_mb__after_atomic(); smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn); smc_tx_sndbuf_nonfull(smc); return rc; } /********************************* receive ***********************************/ static inline bool smc_cdc_before(u16 seq1, u16 seq2) { return (s16)(seq1 - seq2) < 0; } static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc, int *diff_prod) { struct smc_connection *conn = &smc->conn; char *base; /* new data included urgent business */ smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn); conn->urg_state = SMC_URG_VALID; if (!sock_flag(&smc->sk, SOCK_URGINLINE)) /* we'll skip the urgent byte, so don't account for it */ (*diff_prod)--; base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off; if (conn->urg_curs.count) conn->urg_rx_byte = *(base + conn->urg_curs.count - 1); else conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1); sk_send_sigurg(&smc->sk); } static void smc_cdc_msg_validate(struct smc_sock *smc, struct smc_cdc_msg *cdc, struct smc_link *link) { struct smc_connection *conn = &smc->conn; u16 recv_seq = ntohs(cdc->seqno); s16 diff; /* check that seqnum was seen before */ diff = conn->local_rx_ctrl.seqno - recv_seq; if (diff < 0) { /* diff larger than 0x7fff */ /* drop connection */ conn->out_of_sync = 1; /* prevent any further receives */ spin_lock_bh(&conn->send_lock); conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; conn->lnk = link; spin_unlock_bh(&conn->send_lock); sock_hold(&smc->sk); /* sock_put in abort_work */ if (!queue_work(smc_close_wq, &conn->abort_work)) sock_put(&smc->sk); } } static void smc_cdc_msg_recv_action(struct smc_sock *smc, struct smc_cdc_msg *cdc) { union smc_host_cursor cons_old, prod_old; struct smc_connection *conn = &smc->conn; int diff_cons, diff_prod; smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn); smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn); smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn); diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old, &conn->local_rx_ctrl.cons); if (diff_cons) { /* peer_rmbe_space is decreased during data transfer with RDMA * write */ smp_mb__before_atomic(); atomic_add(diff_cons, &conn->peer_rmbe_space); /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */ smp_mb__after_atomic(); } diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old, &conn->local_rx_ctrl.prod); if (diff_prod) { if (conn->local_rx_ctrl.prod_flags.urg_data_present) smc_cdc_handle_urg_data_arrival(smc, &diff_prod); /* bytes_to_rcv is decreased in smc_recvmsg */ smp_mb__before_atomic(); atomic_add(diff_prod, &conn->bytes_to_rcv); /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */ smp_mb__after_atomic(); smc->sk.sk_data_ready(&smc->sk); } else { if (conn->local_rx_ctrl.prod_flags.write_blocked) smc->sk.sk_data_ready(&smc->sk); if (conn->local_rx_ctrl.prod_flags.urg_data_pending) conn->urg_state = SMC_URG_NOTYET; } /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */ if ((diff_cons && smc_tx_prepared_sends(conn)) || conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || conn->local_rx_ctrl.prod_flags.urg_data_pending) smc_tx_sndbuf_nonempty(conn); if (diff_cons && conn->urg_tx_pend && atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) { /* urg data confirmed by peer, indicate we're ready for more */ conn->urg_tx_pend = false; smc->sk.sk_write_space(&smc->sk); } if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) { smc->sk.sk_err = ECONNRESET; conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; } if (smc_cdc_rxed_any_close_or_senddone(conn)) { smc->sk.sk_shutdown |= RCV_SHUTDOWN; if (smc->clcsock && smc->clcsock->sk) smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN; sock_set_flag(&smc->sk, SOCK_DONE); sock_hold(&smc->sk); /* sock_put in close_work */ if (!queue_work(smc_close_wq, &conn->close_work)) sock_put(&smc->sk); } } /* called under tasklet context */ static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc) { sock_hold(&smc->sk); bh_lock_sock(&smc->sk); smc_cdc_msg_recv_action(smc, cdc); bh_unlock_sock(&smc->sk); sock_put(&smc->sk); /* no free sk in softirq-context */ } /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ * handler to indicate update in the DMBE. * * Context: * - tasklet context */ static void smcd_cdc_rx_tsklet(struct tasklet_struct *t) { struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet); struct smcd_cdc_msg *data_cdc; struct smcd_cdc_msg cdc; struct smc_sock *smc; if (!conn || conn->killed) return; data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr; smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn); smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn); smc = container_of(conn, struct smc_sock, conn); smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc); } /* Initialize receive tasklet. Called from ISM device IRQ handler to start * receiver side. */ void smcd_cdc_rx_init(struct smc_connection *conn) { tasklet_setup(&conn->rx_tsklet, smcd_cdc_rx_tsklet); } /***************************** init, exit, misc ******************************/ static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf) { struct smc_link *link = (struct smc_link *)wc->qp->qp_context; struct smc_cdc_msg *cdc = buf; struct smc_connection *conn; struct smc_link_group *lgr; struct smc_sock *smc; if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved)) return; /* short message */ if (cdc->len != SMC_WR_TX_SIZE) return; /* invalid message */ /* lookup connection */ lgr = smc_get_lgr(link); read_lock_bh(&lgr->conns_lock); conn = smc_lgr_find_conn(ntohl(cdc->token), lgr); read_unlock_bh(&lgr->conns_lock); if (!conn || conn->out_of_sync) return; smc = container_of(conn, struct smc_sock, conn); if (cdc->prod_flags.failover_validation) { smc_cdc_msg_validate(smc, cdc, link); return; } if (smc_cdc_before(ntohs(cdc->seqno), conn->local_rx_ctrl.seqno)) /* received seqno is old */ return; smc_cdc_msg_recv(smc, cdc); } static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = { { .handler = smc_cdc_rx_handler, .type = SMC_CDC_MSG_TYPE }, { .handler = NULL, } }; int __init smc_cdc_init(void) { struct smc_wr_rx_handler *handler; int rc = 0; for (handler = smc_cdc_rx_handlers; handler->handler; handler++) { INIT_HLIST_NODE(&handler->list); rc = smc_wr_rx_register_handler(handler); if (rc) break; } return rc; }