net/smc: first part of add link processing as SMC server

First set of functions to process an ADD_LINK LLC request as an SMC
server. Find an alternate IB device, determine the new link group type
and get the index for the new link. Then initialize the link and send
the ADD_LINK LLC message to the peer. Save the contents of the response,
ready the link, map all used buffers and register the buffers with the
IB device. If any error occurs, stop the processing and clear the link.
And call smc_llc_srv_add_link() in af_smc.c to start second link
establishment after the initial link of a link group was created.

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

@@ -1067,7 +1067,7 @@ static int smcr_serv_conf_first_link(struct smc_sock *smc)
 	smc_llc_link_active(link);
 
 	/* initial contact - try to establish second link */
-	/* tbd: call smc_llc_srv_add_link(link); */
+	smc_llc_srv_add_link(link);
 	return 0;
 }
 

net/smc/smc_llc.c

@@ -863,6 +863,94 @@ static void smc_llc_process_cli_add_link(struct smc_link_group *lgr)
 	mutex_unlock(&lgr->llc_conf_mutex);
 }
 
+int smc_llc_srv_add_link(struct smc_link *link)
+{
+	enum smc_lgr_type lgr_new_t = SMC_LGR_SYMMETRIC;
+	struct smc_link_group *lgr = link->lgr;
+	struct smc_llc_msg_add_link *add_llc;
+	struct smc_llc_qentry *qentry = NULL;
+	struct smc_link *link_new;
+	struct smc_init_info ini;
+	int lnk_idx, rc = 0;
+
+	/* ignore client add link recommendation, start new flow */
+	ini.vlan_id = lgr->vlan_id;
+	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
+	if (!ini.ib_dev) {
+		lgr_new_t = SMC_LGR_ASYMMETRIC_LOCAL;
+		ini.ib_dev = link->smcibdev;
+		ini.ib_port = link->ibport;
+	}
+	lnk_idx = smc_llc_alloc_alt_link(lgr, lgr_new_t);
+	if (lnk_idx < 0)
+		return 0;
+
+	rc = smcr_link_init(lgr, &lgr->lnk[lnk_idx], lnk_idx, &ini);
+	if (rc)
+		return rc;
+	link_new = &lgr->lnk[lnk_idx];
+	rc = smc_llc_send_add_link(link,
+				   link_new->smcibdev->mac[ini.ib_port - 1],
+				   link_new->gid, link_new, SMC_LLC_REQ);
+	if (rc)
+		goto out_err;
+	/* receive ADD LINK response over the RoCE fabric */
+	qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_TIME, SMC_LLC_ADD_LINK);
+	if (!qentry) {
+		rc = -ETIMEDOUT;
+		goto out_err;
+	}
+	add_llc = &qentry->msg.add_link;
+	if (add_llc->hd.flags & SMC_LLC_FLAG_ADD_LNK_REJ) {
+		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
+		rc = -ENOLINK;
+		goto out_err;
+	}
+	if (lgr->type == SMC_LGR_SINGLE &&
+	    (!memcmp(add_llc->sender_gid, link->peer_gid, SMC_GID_SIZE) &&
+	     !memcmp(add_llc->sender_mac, link->peer_mac, ETH_ALEN))) {
+		lgr_new_t = SMC_LGR_ASYMMETRIC_PEER;
+	}
+	smc_llc_save_add_link_info(link_new, add_llc);
+	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
+
+	rc = smc_ib_ready_link(link_new);
+	if (rc)
+		goto out_err;
+	rc = smcr_buf_map_lgr(link_new);
+	if (rc)
+		goto out_err;
+	rc = smcr_buf_reg_lgr(link_new);
+	if (rc)
+		goto out_err;
+	/* tbd: rc = smc_llc_srv_rkey_exchange(link, link_new); */
+	if (rc)
+		goto out_err;
+	/* tbd: rc = smc_llc_srv_conf_link(link, link_new, lgr_new_t); */
+	if (rc)
+		goto out_err;
+	return 0;
+out_err:
+	smcr_link_clear(link_new);
+	return rc;
+}
+
+static void smc_llc_process_srv_add_link(struct smc_link_group *lgr)
+{
+	struct smc_link *link = lgr->llc_flow_lcl.qentry->link;
+	int rc;
+
+	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
+
+	mutex_lock(&lgr->llc_conf_mutex);
+	rc = smc_llc_srv_add_link(link);
+	if (!rc && lgr->type == SMC_LGR_SYMMETRIC) {
+		/* delete any asymmetric link */
+		/* tbd: smc_llc_delete_asym_link(lgr); */
+	}
+	mutex_unlock(&lgr->llc_conf_mutex);
+}
+
 /* worker to process an add link message */
 static void smc_llc_add_link_work(struct work_struct *work)
 {
@@ -877,7 +965,8 @@ static void smc_llc_add_link_work(struct work_struct *work)
 
 	if (lgr->role == SMC_CLNT)
 		smc_llc_process_cli_add_link(lgr);
-	/* tbd: call smc_llc_process_srv_add_link(lgr); */
+	else
+		smc_llc_process_srv_add_link(lgr);
 out:
 	smc_llc_flow_stop(lgr, &lgr->llc_flow_lcl);
 }

net/smc/smc_llc.h

@@ -89,6 +89,7 @@ struct smc_llc_qentry *smc_llc_wait(struct smc_link_group *lgr,
 struct smc_llc_qentry *smc_llc_flow_qentry_clr(struct smc_llc_flow *flow);
 void smc_llc_flow_qentry_del(struct smc_llc_flow *flow);
 int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry);
+int smc_llc_srv_add_link(struct smc_link *link);
 int smc_llc_init(void) __init;
 
 #endif /* SMC_LLC_H */