net/smc: adapt SMC client code to use the LLC flow

Change the code that processes the SMC client part of connection
establishment to use the LLC flow framework (CONFIRM_LINK request
messages).
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -382,22 +382,24 @@ static int smcr_lgr_reg_rmbs(struct smc_link_group *lgr,
 static int smcr_clnt_conf_first_link(struct smc_sock *smc)
 {
 	struct smc_link *link = smc->conn.lnk;
-	int rest;
+	struct smc_llc_qentry *qentry;
 	int rc;
 
+	link->lgr->type = SMC_LGR_SINGLE;
+
 	/* receive CONFIRM LINK request from server over RoCE fabric */
-	rest = wait_for_completion_interruptible_timeout(
-		&link->llc_confirm,
-		SMC_LLC_WAIT_FIRST_TIME);
-	if (rest <= 0) {
+	qentry = smc_llc_wait(link->lgr, NULL, SMC_LLC_WAIT_TIME,
+			      SMC_LLC_CONFIRM_LINK);
+	if (!qentry) {
 		struct smc_clc_msg_decline dclc;
 
 		rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
 				      SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
 		return rc == -EAGAIN ? SMC_CLC_DECL_TIMEOUT_CL : rc;
 	}
-
-	if (link->llc_confirm_rc)
+	rc = smc_llc_eval_conf_link(qentry, SMC_LLC_REQ);
+	smc_llc_flow_qentry_del(&link->lgr->llc_flow_lcl);
+	if (rc)
 		return SMC_CLC_DECL_RMBE_EC;
 
 	rc = smc_ib_modify_qp_rts(link);
@@ -409,31 +411,30 @@ static int smcr_clnt_conf_first_link(struct smc_sock *smc)
 	if (smcr_link_reg_rmb(link, smc->conn.rmb_desc, false))
 		return SMC_CLC_DECL_ERR_REGRMB;
 
+	/* confirm_rkey is implicit on 1st contact */
+	smc->conn.rmb_desc->is_conf_rkey = true;
+
 	/* send CONFIRM LINK response over RoCE fabric */
 	rc = smc_llc_send_confirm_link(link, SMC_LLC_RESP);
 	if (rc < 0)
 		return SMC_CLC_DECL_TIMEOUT_CL;
 
-	/* receive ADD LINK request from server over RoCE fabric */
-	rest = wait_for_completion_interruptible_timeout(&link->llc_add,
-							 SMC_LLC_WAIT_TIME);
-	if (rest <= 0) {
+	smc_llc_link_active(link);
+
+	/* optional 2nd link, receive ADD LINK request from server */
+	qentry = smc_llc_wait(link->lgr, NULL, SMC_LLC_WAIT_TIME,
+			      SMC_LLC_ADD_LINK);
+	if (!qentry) {
 		struct smc_clc_msg_decline dclc;
 
 		rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
 				      SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
-		return rc == -EAGAIN ? SMC_CLC_DECL_TIMEOUT_AL : rc;
+		if (rc == -EAGAIN)
+			rc = 0; /* no DECLINE received, go with one link */
+		return rc;
 	}
-
-	/* send add link reject message, only one link supported for now */
-	rc = smc_llc_send_add_link(link,
-				   link->smcibdev->mac[link->ibport - 1],
-				   link->gid, SMC_LLC_RESP);
-	if (rc < 0)
-		return SMC_CLC_DECL_TIMEOUT_AL;
-
-	smc_llc_link_active(link);
-
+	smc_llc_flow_qentry_clr(&link->lgr->llc_flow_lcl);
+	/* tbd: call smc_llc_cli_add_link(link, qentry); */
 	return 0;
 }
 
@@ -613,8 +614,8 @@ static int smc_connect_rdma(struct smc_sock *smc,
 			    struct smc_clc_msg_accept_confirm *aclc,
 			    struct smc_init_info *ini)
 {
+	int i, reason_code = 0;
 	struct smc_link *link;
-	int reason_code = 0;
 
 	ini->is_smcd = false;
 	ini->ib_lcl = &aclc->lcl;
@@ -627,10 +628,28 @@ static int smc_connect_rdma(struct smc_sock *smc,
 		mutex_unlock(&smc_client_lgr_pending);
 		return reason_code;
 	}
-	link = smc->conn.lnk;
 
 	smc_conn_save_peer_info(smc, aclc);
 
+	if (ini->cln_first_contact == SMC_FIRST_CONTACT) {
+		link = smc->conn.lnk;
+	} else {
+		/* set link that was assigned by server */
+		link = NULL;
+		for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
+			struct smc_link *l = &smc->conn.lgr->lnk[i];
+
+			if (l->peer_qpn == ntoh24(aclc->qpn)) {
+				link = l;
+				break;
+			}
+		}
+		if (!link)
+			return smc_connect_abort(smc, SMC_CLC_DECL_NOSRVLINK,
+						 ini->cln_first_contact);
+		smc->conn.lnk = link;
+	}
+
 	/* create send buffer and rmb */
 	if (smc_buf_create(smc, false))
 		return smc_connect_abort(smc, SMC_CLC_DECL_MEM,
@@ -666,7 +685,9 @@ static int smc_connect_rdma(struct smc_sock *smc,
 
 	if (ini->cln_first_contact == SMC_FIRST_CONTACT) {
 		/* QP confirmation over RoCE fabric */
+		smc_llc_flow_initiate(link->lgr, SMC_LLC_FLOW_ADD_LINK);
 		reason_code = smcr_clnt_conf_first_link(smc);
+		smc_llc_flow_stop(link->lgr, &link->lgr->llc_flow_lcl);
 		if (reason_code)
 			return smc_connect_abort(smc, reason_code,
 						 ini->cln_first_contact);

net/smc/smc_clc.h

@@ -45,6 +45,7 @@
 #define SMC_CLC_DECL_GETVLANERR	0x03080000  /* err to get vlan id of ip device*/
 #define SMC_CLC_DECL_ISMVLANERR	0x03090000  /* err to reg vlan id on ism dev  */
 #define SMC_CLC_DECL_NOACTLINK	0x030a0000  /* no active smc-r link in lgr    */
+#define SMC_CLC_DECL_NOSRVLINK	0x030b0000  /* SMC-R link from srv not found  */
 #define SMC_CLC_DECL_SYNCERR	0x04000000  /* synchronization error          */
 #define SMC_CLC_DECL_PEERDECL	0x05000000  /* peer declined during handshake */
 #define SMC_CLC_DECL_INTERR	0x09990000  /* internal error		      */

net/smc/smc_core.h

@@ -120,9 +120,6 @@ struct smc_link {
 	struct smc_link_group	*lgr;		/* parent link group */
 
 	enum smc_link_state	state;		/* state of link */
-	struct completion	llc_confirm;	/* wait for rx of conf link */
-	int			llc_confirm_rc; /* rc from confirm link msg */
-	struct completion	llc_add;	/* wait for rx of add link */
 	struct delayed_work	llc_testlink_wrk; /* testlink worker */
 	struct completion	llc_testlink_resp; /* wait for rx of testlink */
 	int			llc_testlink_time; /* testlink interval */

net/smc/smc_llc.c

@@ -528,47 +528,6 @@ static int smc_llc_send_message(struct smc_link *link, void *llcbuf)
 
 /********************************* receive ***********************************/
 
-static void smc_llc_rx_confirm_link(struct smc_link *link,
-				    struct smc_llc_msg_confirm_link *llc)
-{
-	struct smc_link_group *lgr = smc_get_lgr(link);
-	int conf_rc = 0;
-
-	/* RMBE eyecatchers are not supported */
-	if (!(llc->hd.flags & SMC_LLC_FLAG_NO_RMBE_EYEC))
-		conf_rc = ENOTSUPP;
-
-	if (lgr->role == SMC_CLNT &&
-	    link->state == SMC_LNK_ACTIVATING) {
-		link->llc_confirm_rc = conf_rc;
-		link->link_id = llc->link_num;
-		complete(&link->llc_confirm);
-	}
-}
-
-static void smc_llc_rx_add_link(struct smc_link *link,
-				struct smc_llc_msg_add_link *llc)
-{
-	struct smc_link_group *lgr = smc_get_lgr(link);
-
-	if (link->state == SMC_LNK_ACTIVATING) {
-		complete(&link->llc_add);
-		return;
-	}
-
-	if (lgr->role == SMC_SERV) {
-		smc_llc_prep_add_link(llc, link,
-				link->smcibdev->mac[link->ibport - 1],
-				link->gid, SMC_LLC_REQ);
-
-	} else {
-		smc_llc_prep_add_link(llc, link,
-				link->smcibdev->mac[link->ibport - 1],
-				link->gid, SMC_LLC_RESP);
-	}
-	smc_llc_send_message(link, llc);
-}
-
 static void smc_llc_rx_delete_link(struct smc_link *link,
 				   struct smc_llc_msg_del_link *llc)
 {
@@ -657,6 +616,7 @@ static void smc_llc_event_handler(struct smc_llc_qentry *qentry)
 {
 	union smc_llc_msg *llc = &qentry->msg;
 	struct smc_link *link = qentry->link;
+	struct smc_link_group *lgr = link->lgr;
 
 	if (!smc_link_usable(link))
 		goto out;
@@ -665,11 +625,31 @@ static void smc_llc_event_handler(struct smc_llc_qentry *qentry)
 	case SMC_LLC_TEST_LINK:
 		smc_llc_rx_test_link(link, &llc->test_link);
 		break;
-	case SMC_LLC_CONFIRM_LINK:
-		smc_llc_rx_confirm_link(link, &llc->confirm_link);
-		break;
 	case SMC_LLC_ADD_LINK:
-		smc_llc_rx_add_link(link, &llc->add_link);
+		if (list_empty(&lgr->list))
+			goto out;	/* lgr is terminating */
+		if (lgr->role == SMC_CLNT) {
+			if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK) {
+				/* a flow is waiting for this message */
+				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
+							qentry);
+				wake_up_interruptible(&lgr->llc_waiter);
+			} else if (smc_llc_flow_start(&lgr->llc_flow_lcl,
+						      qentry)) {
+				/* tbd: schedule_work(&lgr->llc_add_link_work); */
+			}
+		} else if (smc_llc_flow_start(&lgr->llc_flow_lcl, qentry)) {
+			/* as smc server, handle client suggestion */
+			/* tbd: schedule_work(&lgr->llc_add_link_work); */
+		}
+		return;
+	case SMC_LLC_CONFIRM_LINK:
+		if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) {
+			/* a flow is waiting for this message */
+			smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry);
+			wake_up_interruptible(&lgr->llc_waiter);
+			return;
+		}
 		break;
 	case SMC_LLC_DELETE_LINK:
 		smc_llc_rx_delete_link(link, &llc->delete_link);
@@ -857,8 +837,6 @@ void smc_llc_lgr_clear(struct smc_link_group *lgr)
 
 int smc_llc_link_init(struct smc_link *link)
 {
-	init_completion(&link->llc_confirm);
-	init_completion(&link->llc_add);
 	init_completion(&link->llc_confirm_rkey_resp);
 	init_completion(&link->llc_delete_rkey_resp);
 	mutex_init(&link->llc_delete_rkey_mutex);