net/smc: support max links per lgr negotiation in clc handshake

Support max links per lgr negotiation in clc handshake for SMCR v2.1,
which is one of smc v2.1 features. Server makes decision for the final
value of max links based on the client preferred max links and
self-preferred max links. Here use the minimum value of the client
preferred max links and server preferred max links.

Client                                       Server
     Proposal(max links(client preferred))
     -------------------------------------->

     Accept(max links(accepted value))
accepted value=min(client preferred, server preferred)
     <-------------------------------------

      Confirm(max links(accepted value))
     ------------------------------------->

Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Reviewed-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 17 deletions

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 9a72eb8d3038..c4f664fb2bcb 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -641,20 +641,22 @@ static int smcr_clnt_conf_first_link(struct smc_sock *smc)
 	smc_llc_link_active(link);
 	smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);
 
-	/* 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);
-		if (rc == -EAGAIN)
-			rc = 0; /* no DECLINE received, go with one link */
-		return rc;
+	if (link->lgr->max_links > 1) {
+		/* 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);
+			if (rc == -EAGAIN)
+				rc = 0; /* no DECLINE received, go with one link */
+			return rc;
+		}
+		smc_llc_flow_qentry_clr(&link->lgr->llc_flow_lcl);
+		smc_llc_cli_add_link(link, qentry);
 	}
-	smc_llc_flow_qentry_clr(&link->lgr->llc_flow_lcl);
-	smc_llc_cli_add_link(link, qentry);
 	return 0;
 }
 
@@ -1243,6 +1245,7 @@ static int smc_connect_rdma(struct smc_sock *smc,
 	memcpy(ini->peer_gid, aclc->r0.lcl.gid, SMC_GID_SIZE);
 	memcpy(ini->peer_mac, aclc->r0.lcl.mac, ETH_ALEN);
 	ini->max_conns = SMC_CONN_PER_LGR_MAX;
+	ini->max_links = SMC_LINKS_ADD_LNK_MAX;
 
 	reason_code = smc_connect_rdma_v2_prepare(smc, aclc, ini);
 	if (reason_code)
@@ -1887,10 +1890,12 @@ static int smcr_serv_conf_first_link(struct smc_sock *smc)
 	smc_llc_link_active(link);
 	smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);
 
-	down_write(&link->lgr->llc_conf_mutex);
-	/* initial contact - try to establish second link */
-	smc_llc_srv_add_link(link, NULL);
-	up_write(&link->lgr->llc_conf_mutex);
+	if (link->lgr->max_links > 1) {
+		down_write(&link->lgr->llc_conf_mutex);
+		/* initial contact - try to establish second link */
+		smc_llc_srv_add_link(link, NULL);
+		up_write(&link->lgr->llc_conf_mutex);
+	}
 	return 0;
 }
 
@@ -2494,6 +2499,11 @@ static void smc_listen_work(struct work_struct *work)
 		goto out_decl;
 	}
 
+	/* fce smc release version is needed in smc_listen_rdma_finish,
+	 * so save fce info here.
+	 */
+	smc_conn_save_peer_info_fce(new_smc, cclc);
+
 	/* finish worker */
 	if (!ini->is_smcd) {
 		rc = smc_listen_rdma_finish(new_smc, cclc,