net/smc: move add link processing for new device into llc layer

When a new ib device is up smc will send an add link invitation to the
peer if needed. This is currently done with rudimentary flow control.
Under high workload these add link invitations can disturb other llc
flows because they arrive unexpected. Fix this by integrating the
invitations into the normal llc event flow and handle them as a flow.
While at it, check for already assigned requests in the flow before
the new add link request is assigned.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: 1f90a05d9ff9 ("net/smc: add smcr_port_add() and smcr_link_up() processing")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 50 insertions, 6 deletions

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index 78704f03e72a..30da040ab5b6 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -895,6 +895,36 @@ out:
 	return rc;
 }
 
+/* as an SMC client, invite server to start the add_link processing */
+static void smc_llc_cli_add_link_invite(struct smc_link *link,
+					struct smc_llc_qentry *qentry)
+{
+	struct smc_link_group *lgr = smc_get_lgr(link);
+	struct smc_init_info ini;
+
+	if (lgr->type == SMC_LGR_SYMMETRIC ||
+	    lgr->type == SMC_LGR_ASYMMETRIC_PEER)
+		goto out;
+
+	ini.vlan_id = lgr->vlan_id;
+	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
+	if (!ini.ib_dev)
+		goto out;
+
+	smc_llc_send_add_link(link, ini.ib_dev->mac[ini.ib_port - 1],
+			      ini.ib_gid, NULL, SMC_LLC_REQ);
+out:
+	kfree(qentry);
+}
+
+static bool smc_llc_is_local_add_link(union smc_llc_msg *llc)
+{
+	if (llc->raw.hdr.common.type == SMC_LLC_ADD_LINK &&
+	    !llc->add_link.qp_mtu && !llc->add_link.link_num)
+		return true;
+	return false;
+}
+
 static void smc_llc_process_cli_add_link(struct smc_link_group *lgr)
 {
 	struct smc_llc_qentry *qentry;
@@ -902,7 +932,10 @@ static void smc_llc_process_cli_add_link(struct smc_link_group *lgr)
 	qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl);
 
 	mutex_lock(&lgr->llc_conf_mutex);
-	smc_llc_cli_add_link(qentry->link, qentry);
+	if (smc_llc_is_local_add_link(&qentry->msg))
+		smc_llc_cli_add_link_invite(qentry->link, qentry);
+	else
+		smc_llc_cli_add_link(qentry->link, qentry);
 	mutex_unlock(&lgr->llc_conf_mutex);
 }
 
@@ -1160,14 +1193,14 @@ static void smc_llc_process_srv_add_link(struct smc_link_group *lgr)
 	mutex_unlock(&lgr->llc_conf_mutex);
 }
 
-/* enqueue a local add_link req to trigger a new add_link flow, only as SERV */
-void smc_llc_srv_add_link_local(struct smc_link *link)
+/* enqueue a local add_link req to trigger a new add_link flow */
+void smc_llc_add_link_local(struct smc_link *link)
 {
 	struct smc_llc_msg_add_link add_llc = {0};
 
 	add_llc.hd.length = sizeof(add_llc);
 	add_llc.hd.common.type = SMC_LLC_ADD_LINK;
-	/* no dev and port needed, we as server ignore client data anyway */
+	/* no dev and port needed */
 	smc_llc_enqueue(link, (union smc_llc_msg *)&add_llc);
 }
 
@@ -1347,7 +1380,7 @@ static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr)
 
 	if (lgr->type == SMC_LGR_SINGLE && !list_empty(&lgr->list)) {
 		/* trigger setup of asymm alt link */
-		smc_llc_srv_add_link_local(lnk);
+		smc_llc_add_link_local(lnk);
 	}
 out:
 	mutex_unlock(&lgr->llc_conf_mutex);
@@ -1476,7 +1509,18 @@ static void smc_llc_event_handler(struct smc_llc_qentry *qentry)
 		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) {
+			if (smc_llc_is_local_add_link(llc)) {
+				if (lgr->llc_flow_lcl.type ==
+				    SMC_LLC_FLOW_ADD_LINK)
+					break;	/* add_link in progress */
+				if (smc_llc_flow_start(&lgr->llc_flow_lcl,
+						       qentry)) {
+					schedule_work(&lgr->llc_add_link_work);
+				}
+				return;
+			}
+			if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK &&
+			    !lgr->llc_flow_lcl.qentry) {
 				/* a flow is waiting for this message */
 				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
 							qentry);