netdev - [RFC net-next] net/smc: update peer ID on device changes

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Message-Id: <20200227113902.318060-1-ndev@hwipl.net>
Date:   Thu, 27 Feb 2020 12:39:02 +0100
From:   Hans Wippel <ndev@...pl.net>
To:     kgraul@...ux.ibm.com, ubraun@...ux.ibm.com, davem@...emloft.net
Cc:     netdev@...r.kernel.org, hwipl <ndev@...pl.net>
Subject: [RFC net-next] net/smc: update peer ID on device changes

From: hwipl <ndev@...pl.net>

A SMC host's peer ID contains the MAC address of the first active RoCE
device. However, if this device becomes inactive or is removed, the peer
ID is not updated. This patch adds peer ID updates on device changes.

Signed-off-by: hwipl <ndev@...pl.net>
---
 net/smc/smc_ib.c | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index 3444de27fecd..5818636962c6 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -159,11 +159,29 @@ static int smc_ib_fill_mac(struct smc_ib_device *smcibdev, u8 ibport)
  * plus a random 2-byte number is used to create this identifier.
  * This name is delivered to the peer during connection initialization.
  */
-static inline void smc_ib_define_local_systemid(struct smc_ib_device *smcibdev,
-						u8 ibport)
+static void smc_ib_update_local_systemid(void)
 {
-	memcpy(&local_systemid[2], &smcibdev->mac[ibport - 1],
-	       sizeof(smcibdev->mac[ibport - 1]));
+	struct smc_ib_device *smcibdev;
+	u8 ibport;
+
+	/* get first ib device with an active port */
+	spin_lock(&smc_ib_devices.lock);
+	list_for_each_entry(smcibdev, &smc_ib_devices.list, list) {
+		for (ibport = 1; ibport <= SMC_MAX_PORTS; ibport++) {
+			if (smc_ib_port_active(smcibdev, ibport))
+				goto out;
+		}
+	}
+	smcibdev = NULL;
+out:
+	spin_unlock(&smc_ib_devices.lock);
+
+	/* set (new) mac address or reset to zero */
+	if (smcibdev)
+		ether_addr_copy(&local_systemid[2],
+				(u8 *)&smcibdev->mac[ibport - 1]);
+	else
+		eth_zero_addr(&local_systemid[2]);
 }
 
 bool smc_ib_is_valid_local_systemid(void)
@@ -229,10 +247,6 @@ static int smc_ib_remember_port_attr(struct smc_ib_device *smcibdev, u8 ibport)
 	rc = smc_ib_fill_mac(smcibdev, ibport);
 	if (rc)
 		goto out;
-	if (!smc_ib_is_valid_local_systemid() &&
-	    smc_ib_port_active(smcibdev, ibport))
-		/* create unique system identifier */
-		smc_ib_define_local_systemid(smcibdev, ibport);
 out:
 	return rc;
 }
@@ -254,6 +268,7 @@ static void smc_ib_port_event_work(struct work_struct *work)
 			clear_bit(port_idx, smcibdev->ports_going_away);
 		}
 	}
+	smc_ib_update_local_systemid();
 }
 
 /* can be called in IRQ context */
@@ -599,6 +614,7 @@ static void smc_ib_remove_dev(struct ib_device *ibdev, void *client_data)
 	smc_ib_cleanup_per_ibdev(smcibdev);
 	ib_unregister_event_handler(&smcibdev->event_handler);
 	kfree(smcibdev);
+	smc_ib_update_local_systemid();
 }
 
 static struct ib_client smc_ib_client = {
-- 
2.25.1