From c6f02ebeea3a0ff4bddddf0fd82303190ebb3dd1 Mon Sep 17 00:00:00 2001 From: Karsten Graul Date: Mon, 4 May 2020 14:18:38 +0200 Subject: [PATCH] net/smc: switch connections to alternate link Add smc_switch_conns() to switch all connections from a link that is going down. Find an other link to switch the connections to, and switch each connection to the new link. smc_switch_cursor() updates the cursors of a connection to the state of the last successfully sent CDC message. When there is no link to switch to, terminate the link group. Call smc_switch_conns() when a link is going down. And with the possibility that links of connections can switch adapt CDC and TX functions to detect and handle link switches. Signed-off-by: Karsten Graul Reviewed-by: Ursula Braun Signed-off-by: David S. Miller --- net/smc/smc_cdc.c | 18 ++++++- net/smc/smc_cdc.h | 1 + net/smc/smc_core.c | 132 ++++++++++++++++++++++++++++++++++++++++++++- net/smc/smc_core.h | 2 + net/smc/smc_llc.c | 6 +-- net/smc/smc_tx.c | 12 ++++- 6 files changed, 162 insertions(+), 9 deletions(-) diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c index c5e33296e55c..3ca986066f32 100644 --- a/net/smc/smc_cdc.c +++ b/net/smc/smc_cdc.c @@ -56,11 +56,11 @@ static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd, } 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) { - struct smc_link *link = conn->lnk; int rc; rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf, @@ -119,13 +119,27 @@ 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; - rc = smc_cdc_get_free_slot(conn, &wr_buf, NULL, &pend); +again: + link = conn->lnk; + rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend); if (rc) return rc; 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); + if (again) + return -ENOLINK; + again = true; + goto again; + } rc = smc_cdc_msg_send(conn, wr_buf, pend); spin_unlock_bh(&conn->send_lock); return rc; diff --git a/net/smc/smc_cdc.h b/net/smc/smc_cdc.h index 861dc24c588c..42246b4bdcc9 100644 --- a/net/smc/smc_cdc.h +++ b/net/smc/smc_cdc.h @@ -304,6 +304,7 @@ struct smc_cdc_tx_pend { }; 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); diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 32a6cadc5c1f..21bc1ec07e99 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -432,6 +432,135 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini) return rc; } +static int smc_write_space(struct smc_connection *conn) +{ + int buffer_len = conn->peer_rmbe_size; + union smc_host_cursor prod; + union smc_host_cursor cons; + int space; + + smc_curs_copy(&prod, &conn->local_tx_ctrl.prod, conn); + smc_curs_copy(&cons, &conn->local_rx_ctrl.cons, conn); + /* determine rx_buf space */ + space = buffer_len - smc_curs_diff(buffer_len, &cons, &prod); + return space; +} + +static int smc_switch_cursor(struct smc_sock *smc) +{ + struct smc_connection *conn = &smc->conn; + union smc_host_cursor cons, fin; + int rc = 0; + int diff; + + smc_curs_copy(&conn->tx_curs_sent, &conn->tx_curs_fin, conn); + smc_curs_copy(&fin, &conn->local_tx_ctrl_fin, conn); + /* set prod cursor to old state, enforce tx_rdma_writes() */ + smc_curs_copy(&conn->local_tx_ctrl.prod, &fin, conn); + smc_curs_copy(&cons, &conn->local_rx_ctrl.cons, conn); + + if (smc_curs_comp(conn->peer_rmbe_size, &cons, &fin) < 0) { + /* cons cursor advanced more than fin, and prod was set + * fin above, so now prod is smaller than cons. Fix that. + */ + diff = smc_curs_diff(conn->peer_rmbe_size, &fin, &cons); + smc_curs_add(conn->sndbuf_desc->len, + &conn->tx_curs_sent, diff); + smc_curs_add(conn->sndbuf_desc->len, + &conn->tx_curs_fin, diff); + + smp_mb__before_atomic(); + atomic_add(diff, &conn->sndbuf_space); + smp_mb__after_atomic(); + + smc_curs_add(conn->peer_rmbe_size, + &conn->local_tx_ctrl.prod, diff); + smc_curs_add(conn->peer_rmbe_size, + &conn->local_tx_ctrl_fin, diff); + } + /* recalculate, value is used by tx_rdma_writes() */ + atomic_set(&smc->conn.peer_rmbe_space, smc_write_space(conn)); + + if (smc->sk.sk_state != SMC_INIT && + smc->sk.sk_state != SMC_CLOSED) { + /* tbd: call rc = smc_cdc_get_slot_and_msg_send(conn); */ + if (!rc) { + schedule_delayed_work(&conn->tx_work, 0); + smc->sk.sk_data_ready(&smc->sk); + } + } + return rc; +} + +struct smc_link *smc_switch_conns(struct smc_link_group *lgr, + struct smc_link *from_lnk, bool is_dev_err) +{ + struct smc_link *to_lnk = NULL; + struct smc_connection *conn; + struct smc_sock *smc; + struct rb_node *node; + int i, rc = 0; + + /* link is inactive, wake up tx waiters */ + smc_wr_wakeup_tx_wait(from_lnk); + + for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) { + if (lgr->lnk[i].state != SMC_LNK_ACTIVE || + i == from_lnk->link_idx) + continue; + if (is_dev_err && from_lnk->smcibdev == lgr->lnk[i].smcibdev && + from_lnk->ibport == lgr->lnk[i].ibport) { + continue; + } + to_lnk = &lgr->lnk[i]; + break; + } + if (!to_lnk) { + smc_lgr_terminate_sched(lgr); + return NULL; + } +again: + read_lock_bh(&lgr->conns_lock); + for (node = rb_first(&lgr->conns_all); node; node = rb_next(node)) { + conn = rb_entry(node, struct smc_connection, alert_node); + if (conn->lnk != from_lnk) + continue; + smc = container_of(conn, struct smc_sock, conn); + /* conn->lnk not yet set in SMC_INIT state */ + if (smc->sk.sk_state == SMC_INIT) + continue; + if (smc->sk.sk_state == SMC_CLOSED || + smc->sk.sk_state == SMC_PEERCLOSEWAIT1 || + smc->sk.sk_state == SMC_PEERCLOSEWAIT2 || + smc->sk.sk_state == SMC_APPFINCLOSEWAIT || + smc->sk.sk_state == SMC_APPCLOSEWAIT1 || + smc->sk.sk_state == SMC_APPCLOSEWAIT2 || + smc->sk.sk_state == SMC_PEERFINCLOSEWAIT || + smc->sk.sk_state == SMC_PEERABORTWAIT || + smc->sk.sk_state == SMC_PROCESSABORT) { + spin_lock_bh(&conn->send_lock); + conn->lnk = to_lnk; + spin_unlock_bh(&conn->send_lock); + continue; + } + sock_hold(&smc->sk); + read_unlock_bh(&lgr->conns_lock); + /* avoid race with smcr_tx_sndbuf_nonempty() */ + spin_lock_bh(&conn->send_lock); + conn->lnk = to_lnk; + rc = smc_switch_cursor(smc); + spin_unlock_bh(&conn->send_lock); + sock_put(&smc->sk); + if (rc) { + smcr_link_down_cond_sched(to_lnk); + return NULL; + } + goto again; + } + read_unlock_bh(&lgr->conns_lock); + return to_lnk; +} + static void smcr_buf_unuse(struct smc_buf_desc *rmb_desc, struct smc_link_group *lgr) { @@ -943,8 +1072,7 @@ static void smcr_link_down(struct smc_link *lnk) return; smc_ib_modify_qp_reset(lnk); - to_lnk = NULL; - /* tbd: call to_lnk = smc_switch_conns(lgr, lnk, true); */ + to_lnk = smc_switch_conns(lgr, lnk, true); if (!to_lnk) { /* no backup link available */ smcr_link_clear(lnk); return; diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h index 7fe53feb9dc4..584f11230c4f 100644 --- a/net/smc/smc_core.h +++ b/net/smc/smc_core.h @@ -380,6 +380,8 @@ void smcr_link_clear(struct smc_link *lnk); int smcr_buf_map_lgr(struct smc_link *lnk); int smcr_buf_reg_lgr(struct smc_link *lnk); int smcr_link_reg_rmb(struct smc_link *link, struct smc_buf_desc *rmb_desc); +struct smc_link *smc_switch_conns(struct smc_link_group *lgr, + struct smc_link *from_lnk, bool is_dev_err); void smcr_link_down_cond(struct smc_link *lnk); void smcr_link_down_cond_sched(struct smc_link *lnk); diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c index 7675ccd6f3c3..8d2368accbad 100644 --- a/net/smc/smc_llc.c +++ b/net/smc/smc_llc.c @@ -933,7 +933,7 @@ static void smc_llc_delete_asym_link(struct smc_link_group *lgr) return; /* no asymmetric link */ if (!smc_link_downing(&lnk_asym->state)) return; - /* tbd: lnk_new = smc_switch_conns(lgr, lnk_asym, false); */ + lnk_new = smc_switch_conns(lgr, lnk_asym, false); smc_wr_tx_wait_no_pending_sends(lnk_asym); if (!lnk_new) goto out_free; @@ -1195,7 +1195,7 @@ static void smc_llc_process_cli_delete_link(struct smc_link_group *lgr) smc_llc_send_message(lnk, &qentry->msg); /* response */ if (smc_link_downing(&lnk_del->state)) { - /* tbd: call smc_switch_conns(lgr, lnk_del, false); */ + smc_switch_conns(lgr, lnk_del, false); smc_wr_tx_wait_no_pending_sends(lnk_del); } smcr_link_clear(lnk_del); @@ -1245,7 +1245,7 @@ static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr) goto out; /* asymmetric link already deleted */ if (smc_link_downing(&lnk_del->state)) { - /* tbd: call smc_switch_conns(lgr, lnk_del, false); */ + smc_switch_conns(lgr, lnk_del, false); smc_wr_tx_wait_no_pending_sends(lnk_del); } if (!list_empty(&lgr->list)) { diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index 417204572a69..54ba0443847e 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -482,12 +482,13 @@ static int smc_tx_rdma_writes(struct smc_connection *conn, 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; - rc = smc_cdc_get_free_slot(conn, &wr_buf, &wr_rdma_buf, &pend); + rc = smc_cdc_get_free_slot(conn, link, &wr_buf, &wr_rdma_buf, &pend); if (rc < 0) { if (rc == -EBUSY) { struct smc_sock *smc = @@ -505,10 +506,17 @@ static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn) } 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(conn->lnk, + smc_wr_tx_put_slot(link, (struct smc_wr_tx_pend_priv *)pend); goto out_unlock; }