/* * 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 *************************************/ struct smc_cdc_tx_pend { struct smc_connection *conn; /* socket connection */ union smc_host_cursor cursor; /* tx sndbuf cursor sent */ union smc_host_cursor p_cursor; /* rx RMBE cursor produced */ u16 ctrl_seq; /* conn. tx sequence # */ }; /* 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_sock *smc; int diff; if (!cdcpend->conn) /* already dismissed */ return; smc = container_of(cdcpend->conn, struct smc_sock, conn); bh_lock_sock(&smc->sk); if (!wc_status) { diff = smc_curs_diff(cdcpend->conn->sndbuf_size, &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_size */ smp_mb__after_atomic(); smc_curs_write(&cdcpend->conn->tx_curs_fin, smc_curs_read(&cdcpend->cursor, cdcpend->conn), cdcpend->conn); } smc_tx_sndbuf_nonfull(smc); if (smc->sk.sk_state != SMC_ACTIVE) /* wake up smc_close_wait_tx_pends() */ smc->sk.sk_state_change(&smc->sk); bh_unlock_sock(&smc->sk); } int smc_cdc_get_free_slot(struct smc_link *link, struct smc_wr_buf **wr_buf, struct smc_cdc_tx_pend **pend) { return smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf, (struct smc_wr_tx_pend_priv **)pend); } 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( offsetof(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; int rc; link = &conn->lgr->lnk[SMC_SINGLE_LINK]; 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->local_tx_ctrl, conn); rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend); if (!rc) smc_curs_write(&conn->rx_curs_confirmed, smc_curs_read(&conn->local_tx_ctrl.cons, conn), conn); return rc; } int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn) { struct smc_cdc_tx_pend *pend; struct smc_wr_buf *wr_buf; int rc; rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], &wr_buf, &pend); if (rc) return rc; return smc_cdc_msg_send(conn, wr_buf, pend); } 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->lgr->lnk[SMC_SINGLE_LINK]; smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE, smc_cdc_tx_filter, smc_cdc_tx_dismisser, (unsigned long)conn); } bool smc_cdc_tx_has_pending(struct smc_connection *conn) { struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK]; return smc_wr_tx_has_pending(link, SMC_CDC_MSG_TYPE, smc_cdc_tx_filter, (unsigned long)conn); } /********************************* receive ***********************************/ static inline bool smc_cdc_before(u16 seq1, u16 seq2) { return (s16)(seq1 - seq2) < 0; } static void smc_cdc_msg_recv_action(struct smc_sock *smc, struct smc_link *link, struct smc_cdc_msg *cdc) { union smc_host_cursor cons_old, prod_old; struct smc_connection *conn = &smc->conn; int diff_cons, diff_prod; if (!cdc->prod_flags.failover_validation) { if (smc_cdc_before(ntohs(cdc->seqno), conn->local_rx_ctrl.seqno)) /* received seqno is old */ return; } smc_curs_write(&prod_old, smc_curs_read(&conn->local_rx_ctrl.prod, conn), conn); smc_curs_write(&cons_old, smc_curs_read(&conn->local_rx_ctrl.cons, conn), 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->rmbe_size, &prod_old, &conn->local_rx_ctrl.prod); if (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 <= rmbe_size */ smp_mb__after_atomic(); smc->sk.sk_data_ready(&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_close_passive_received(smc); /* piggy backed tx info */ /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */ if (diff_cons && smc_tx_prepared_sends(conn)) { smc_tx_sndbuf_nonempty(conn); /* trigger socket release if connection closed */ smc_close_wake_tx_prepared(smc); } /* subsequent patch: trigger socket release if connection closed */ /* socket connected but not accepted */ if (!smc->sk.sk_socket) return; /* data available */ if ((conn->local_rx_ctrl.prod_flags.write_blocked) || (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req)) smc_tx_consumer_update(conn); } /* called under tasklet context */ static inline void smc_cdc_msg_recv(struct smc_cdc_msg *cdc, struct smc_link *link, u64 wr_id) { struct smc_link_group *lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]); struct smc_connection *connection; struct smc_sock *smc; /* lookup connection */ read_lock_bh(&lgr->conns_lock); connection = smc_lgr_find_conn(ntohl(cdc->token), lgr); if (!connection) { read_unlock_bh(&lgr->conns_lock); return; } smc = container_of(connection, struct smc_sock, conn); sock_hold(&smc->sk); read_unlock_bh(&lgr->conns_lock); bh_lock_sock(&smc->sk); smc_cdc_msg_recv_action(smc, link, cdc); bh_unlock_sock(&smc->sk); sock_put(&smc->sk); /* no free sk in softirq-context */ } /***************************** 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; if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved)) return; /* short message */ if (cdc->len != sizeof(*cdc)) return; /* invalid message */ smc_cdc_msg_recv(cdc, link, wc->wr_id); } 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; }