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

Change the code that processes the SMC server part of connection
establishment to use the LLC flow framework (CONFIRM_LINK response
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

@@ -1019,9 +1019,11 @@ void smc_close_non_accepted(struct sock *sk)
 static int smcr_serv_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;
+
 	if (smcr_link_reg_rmb(link, smc->conn.rmb_desc, false))
 		return SMC_CLC_DECL_ERR_REGRMB;
 
@@ -1031,40 +1033,27 @@ static int smcr_serv_conf_first_link(struct smc_sock *smc)
 		return SMC_CLC_DECL_TIMEOUT_CL;
 
 	/* receive CONFIRM LINK response from client over the RoCE fabric */
-	rest = wait_for_completion_interruptible_timeout(
-		&link->llc_confirm_resp,
-		SMC_LLC_WAIT_FIRST_TIME);
-	if (rest <= 0) {
+	qentry = smc_llc_wait(link->lgr, link, 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_resp_rc)
+	rc = smc_llc_eval_conf_link(qentry, SMC_LLC_RESP);
+	smc_llc_flow_qentry_del(&link->lgr->llc_flow_lcl);
+	if (rc)
 		return SMC_CLC_DECL_RMBE_EC;
 
-	/* send ADD LINK request to client over the RoCE fabric */
-	rc = smc_llc_send_add_link(link,
-				   link->smcibdev->mac[link->ibport - 1],
-				   link->gid, SMC_LLC_REQ);
-	if (rc < 0)
-		return SMC_CLC_DECL_TIMEOUT_AL;
-
-	/* receive ADD LINK response from client over the RoCE fabric */
-	rest = wait_for_completion_interruptible_timeout(&link->llc_add_resp,
-							 SMC_LLC_WAIT_TIME);
-	if (rest <= 0) {
-		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;
-	}
+	/* confirm_rkey is implicit on 1st contact */
+	smc->conn.rmb_desc->is_conf_rkey = true;
 
 	smc_llc_link_active(link);
 
+	/* initial contact - try to establish second link */
+	/* tbd: call smc_llc_srv_add_link(link); */
 	return 0;
 }
 
@@ -1240,7 +1229,9 @@ static int smc_listen_rdma_finish(struct smc_sock *new_smc,
 			goto decline;
 		}
 		/* QP confirmation over RoCE fabric */
+		smc_llc_flow_initiate(link->lgr, SMC_LLC_FLOW_ADD_LINK);
 		reason_code = smcr_serv_conf_first_link(new_smc);
+		smc_llc_flow_stop(link->lgr, &link->lgr->llc_flow_lcl);
 		if (reason_code)
 			goto decline;
 	}

net/smc/smc_core.h

@@ -121,11 +121,8 @@ struct smc_link {
 
 	enum smc_link_state	state;		/* state of link */
 	struct completion	llc_confirm;	/* wait for rx of conf link */
-	struct completion	llc_confirm_resp; /* wait 4 rx of cnf lnk rsp */
 	int			llc_confirm_rc; /* rc from confirm link msg */
-	int			llc_confirm_resp_rc; /* rc from conf_resp msg */
 	struct completion	llc_add;	/* wait for rx of add link */
-	struct completion	llc_add_resp;	/* wait for rx of add link rsp*/
 	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

@@ -724,26 +724,18 @@ static void smc_llc_rx_response(struct smc_link *link,
 {
 	u8 llc_type = qentry->msg.raw.hdr.common.type;
 	union smc_llc_msg *llc = &qentry->msg;
-	int rc = 0;
 
 	switch (llc_type) {
 	case SMC_LLC_TEST_LINK:
 		if (link->state == SMC_LNK_ACTIVE)
 			complete(&link->llc_testlink_resp);
 		break;
-	case SMC_LLC_CONFIRM_LINK:
-		if (!(llc->raw.hdr.flags & SMC_LLC_FLAG_NO_RMBE_EYEC))
-			rc = ENOTSUPP;
-		if (link->lgr->role == SMC_SERV &&
-		    link->state == SMC_LNK_ACTIVATING) {
-			link->llc_confirm_resp_rc = rc;
-			complete(&link->llc_confirm_resp);
-		}
-		break;
 	case SMC_LLC_ADD_LINK:
-		if (link->state == SMC_LNK_ACTIVATING)
-			complete(&link->llc_add_resp);
-		break;
+	case SMC_LLC_CONFIRM_LINK:
+		/* assign responses to the local flow, we requested them */
+		smc_llc_flow_qentry_set(&link->lgr->llc_flow_lcl, qentry);
+		wake_up_interruptible(&link->lgr->llc_waiter);
+		return;
 	case SMC_LLC_DELETE_LINK:
 		if (link->lgr->role == SMC_SERV)
 			smc_lgr_schedule_free_work_fast(link->lgr);
@@ -866,9 +858,7 @@ 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_confirm_resp);
 	init_completion(&link->llc_add);
-	init_completion(&link->llc_add_resp);
 	init_completion(&link->llc_confirm_rkey_resp);
 	init_completion(&link->llc_delete_rkey_resp);
 	mutex_init(&link->llc_delete_rkey_mutex);