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-rw-r--r--net/smc/smc_cdc.c280
1 files changed, 280 insertions, 0 deletions
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 <ubraun@linux.vnet.ibm.com>
+ */
+
+#include <linux/spinlock.h>
+
+#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;
+}