1 files changed, 334 insertions, 116 deletions

diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
index a7294edbc221..619b3bab3824 100644
--- a/net/smc/smc_cdc.c
+++ b/net/smc/smc_cdc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Shared Memory Communications over RDMA (SMC-R) and RoCE
  *
@@ -17,57 +18,77 @@
 #include "smc_tx.h"
 #include "smc_rx.h"
 #include "smc_close.h"
+#include "smc_ism.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_connection *conn = cdcpend->conn;
+	struct smc_buf_desc *sndbuf_desc;
 	struct smc_sock *smc;
 	int diff;
 
-	if (!cdcpend->conn)
-		/* already dismissed */
-		return;
-
-	smc = container_of(cdcpend->conn, struct smc_sock, conn);
+	sndbuf_desc = conn->sndbuf_desc;
+	smc = container_of(conn, struct smc_sock, conn);
 	bh_lock_sock(&smc->sk);
-	if (!wc_status) {
-		diff = smc_curs_diff(cdcpend->conn->sndbuf_size,
+	if (!wc_status && sndbuf_desc) {
+		diff = smc_curs_diff(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_size */
+		/* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 		smp_mb__after_atomic();
-		smc_curs_write(&cdcpend->conn->tx_curs_fin,
-			       smc_curs_read(&cdcpend->cursor, cdcpend->conn),
-			       cdcpend->conn);
+		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;
 	}
+
+	if (atomic_dec_and_test(&conn->cdc_pend_tx_wr)) {
+		/* If user owns the sock_lock, mark the connection need sending.
+		 * User context will later try to send when it release sock_lock
+		 * in smc_release_cb()
+		 */
+		if (sock_owned_by_user(&smc->sk))
+			conn->tx_in_release_sock = true;
+		else
+			smc_tx_pending(conn);
+
+		if (unlikely(wq_has_sleeper(&conn->cdc_pend_tx_wq)))
+			wake_up(&conn->cdc_pend_tx_wq);
+	}
+	WARN_ON(atomic_read(&conn->cdc_pend_tx_wr) < 0);
+
 	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,
+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)
 {
-	return smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
-				       (struct smc_wr_tx_pend_priv **)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,
@@ -77,7 +98,7 @@ static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
 		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,
+		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,
@@ -92,73 +113,169 @@ 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;
+	struct smc_link *link = conn->lnk;
+	union smc_host_cursor cfed;
 	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);
+	smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed);
+
+	atomic_inc(&conn->cdc_pend_tx_wr);
+	smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
+
 	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);
+	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;
+		atomic_dec(&conn->cdc_pend_tx_wr);
+	}
 
 	return rc;
 }
 
-int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
+/* 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_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;
 
-	rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], &wr_buf,
-				   &pend);
-	if (rc)
-		return 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;
+
+	/* We need to set pend->conn here to make sure smc_cdc_tx_handler()
+	 * can handle properly
+	 */
+	smc_cdc_add_pending_send(conn, pend);
+
+	atomic_inc(&conn->cdc_pend_tx_wr);
+	smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
 
-	return smc_cdc_msg_send(conn, wr_buf, pend);
+	rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
+	if (unlikely(rc))
+		atomic_dec(&conn->cdc_pend_tx_wr);
+
+	return rc;
 }
 
-static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
-			      unsigned long data)
+static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 {
-	struct smc_connection *conn = (struct smc_connection *)data;
-	struct smc_cdc_tx_pend *cdc_pend =
-		(struct smc_cdc_tx_pend *)tx_pend;
+	struct smc_cdc_tx_pend *pend;
+	struct smc_wr_buf *wr_buf;
+	struct smc_link *link;
+	bool again = false;
+	int rc;
 
-	return cdc_pend->conn == conn;
+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;
 }
 
-static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
+int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 {
-	struct smc_cdc_tx_pend *cdc_pend =
-		(struct smc_cdc_tx_pend *)tx_pend;
+	int rc;
+
+	if (!smc_conn_lgr_valid(conn) ||
+	    (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
+		return -EPIPE;
 
-	cdc_pend->conn = NULL;
+	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;
 }
 
-void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
+void smc_cdc_wait_pend_tx_wr(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);
+	wait_event(conn->cdc_pend_tx_wq, !atomic_read(&conn->cdc_pend_tx_wr));
 }
 
-bool smc_cdc_tx_has_pending(struct smc_connection *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_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
+	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;
 
-	return smc_wr_tx_has_pending(link, SMC_CDC_MSG_TYPE,
-				     smc_cdc_tx_filter, (unsigned long)conn);
+	if (smc_ism_support_dmb_nocopy(conn->lgr->smcd))
+		/* if local sndbuf shares the same memory region with
+		 * peer DMB, then don't update the tx_curs_fin
+		 * and sndbuf_space until peer has consumed the data.
+		 */
+		return 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 0;
 }
 
 /********************************* receive ***********************************/
@@ -168,26 +285,57 @@ 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_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;
+	int diff_cons, diff_prod, diff_tx;
 
-	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_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,
@@ -200,17 +348,64 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 		atomic_add(diff_cons, &conn->peer_rmbe_space);
 		/* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 		smp_mb__after_atomic();
+
+		/* if local sndbuf shares the same memory region with
+		 * peer RMB, then update tx_curs_fin and sndbuf_space
+		 * here since peer has already consumed the data.
+		 */
+		if (conn->lgr->is_smcd &&
+		    smc_ism_support_dmb_nocopy(conn->lgr->smcd)) {
+			/* Calculate consumed data and
+			 * increment free send buffer space.
+			 */
+			diff_tx = smc_curs_diff(conn->sndbuf_desc->len,
+						&conn->tx_curs_fin,
+						&conn->local_rx_ctrl.cons);
+			/* increase local sndbuf space and fin_curs */
+			smp_mb__before_atomic();
+			atomic_add(diff_tx, &conn->sndbuf_space);
+			/* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
+			smp_mb__after_atomic();
+			smc_curs_copy(&conn->tx_curs_fin,
+				      &conn->local_rx_ctrl.cons, conn);
+
+			smc_tx_sndbuf_nonfull(smc);
+		}
 	}
 
-	diff_prod = smc_curs_diff(conn->rmbe_size, &prod_old,
+	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 <= rmbe_size */
+		/* 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) {
+		if (!sock_owned_by_user(&smc->sk))
+			smc_tx_pending(conn);
+		else
+			conn->tx_in_release_sock = true;
+	}
+
+	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) {
@@ -221,65 +416,88 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 		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);
-		schedule_work(&conn->close_work);
+		smc_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);
 	}
-
-	/* 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);
-	}
-
-	/* 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)
+static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 {
-	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);
+	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 != sizeof(*cdc))
+	if (cdc->len != SMC_WR_TX_SIZE)
 		return; /* invalid message */
-	smc_cdc_msg_recv(cdc, link, wc->wr_id);
+
+	/* 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[] = {