net/smc: add pnetid support for SMC-D and ISM

SMC-D relies on PNETIDs to find usable SMC-D/ISM devices for a SMC
connection. This patch adds SMC-D/ISM support to the current PNETID
implementation.

Signed-off-by: Hans Wippel <hwippel@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Suggested-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/smc/smc_pnet.c b/net/smc/smc_pnet.c
index cdc6e23..1b6c066 100644
--- a/net/smc/smc_pnet.c
+++ b/net/smc/smc_pnet.c
@@ -22,6 +22,7 @@
 
 #include "smc_pnet.h"
 #include "smc_ib.h"
+#include "smc_ism.h"
 
 static struct nla_policy smc_pnet_policy[SMC_PNETID_MAX + 1] = {
 	[SMC_PNETID_NAME] = {
@@ -564,6 +565,27 @@ static void smc_pnet_find_roce_by_pnetid(struct net_device *ndev,
 	spin_unlock(&smc_ib_devices.lock);
 }
 
+static void smc_pnet_find_ism_by_pnetid(struct net_device *ndev,
+					struct smcd_dev **smcismdev)
+{
+	u8 ndev_pnetid[SMC_MAX_PNETID_LEN];
+	struct smcd_dev *ismdev;
+
+	ndev = pnet_find_base_ndev(ndev);
+	if (smc_pnetid_by_dev_port(ndev->dev.parent, ndev->dev_port,
+				   ndev_pnetid))
+		return; /* pnetid could not be determined */
+
+	spin_lock(&smcd_dev_list.lock);
+	list_for_each_entry(ismdev, &smcd_dev_list.list, list) {
+		if (!memcmp(ismdev->pnetid, ndev_pnetid, SMC_MAX_PNETID_LEN)) {
+			*smcismdev = ismdev;
+			break;
+		}
+	}
+	spin_unlock(&smcd_dev_list.lock);
+}
+
 /* Lookup of coupled ib_device via SMC pnet table */
 static void smc_pnet_find_roce_by_table(struct net_device *netdev,
 					struct smc_ib_device **smcibdev,
@@ -615,3 +637,22 @@ void smc_pnet_find_roce_resource(struct sock *sk,
 out:
 	return;
 }
+
+void smc_pnet_find_ism_resource(struct sock *sk, struct smcd_dev **smcismdev)
+{
+	struct dst_entry *dst = sk_dst_get(sk);
+
+	*smcismdev = NULL;
+	if (!dst)
+		goto out;
+	if (!dst->dev)
+		goto out_rel;
+
+	/* if possible, lookup via hardware-defined pnetid */
+	smc_pnet_find_ism_by_pnetid(dst->dev, smcismdev);
+
+out_rel:
+	dst_release(dst);
+out:
+	return;
+}