From 5f08318f617b05b6ee389d8bd174c7af921ebf19 Mon Sep 17 00:00:00 2001 From: Ursula Braun Date: Mon, 9 Jan 2017 16:55:22 +0100 Subject: smc: connection data control (CDC) send and receive CDC messages (via IB message send and CQE) Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- net/smc/smc_cdc.c | 280 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 280 insertions(+) create mode 100644 net/smc/smc_cdc.c (limited to 'net/smc/smc_cdc.c') diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c new file mode 100644 index 000000000000..111d23ff9e17 --- /dev/null +++ b/net/smc/smc_cdc.c @@ -0,0 +1,280 @@ +/* + * Shared Memory Communications over RDMA (SMC-R) and RoCE + * + * Connection Data Control (CDC) + * handles flow control + * + * Copyright IBM Corp. 2016 + * + * Author(s): Ursula Braun + */ + +#include + +#include "smc.h" +#include "smc_wr.h" +#include "smc_cdc.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); + } + /* subsequent patch: wake if send buffer space available */ + 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); +} + +/********************************* 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(); + } + + if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) + smc->sk.sk_err = ECONNRESET; + if (smc_cdc_rxed_any_close_or_senddone(conn)) + /* subsequent patch: terminate connection */ + + /* piggy backed tx info */ + /* subsequent patch: wake receivers if receive buffer space available */ + + /* subsequent patch: trigger socket release if connection closed */ + + /* socket connected but not accepted */ + if (!smc->sk.sk_socket) + return; + + /* data available */ + /* subsequent patch: send delayed ack, wake receivers */ +} + +/* 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; +} -- cgit v1.2.3