netdev - [PATCH net-next 6/6] net/smc: reduce port

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Date:   Mon, 17 Feb 2020 16:24:55 +0100
From:   Ursula Braun <ubraun@...ux.ibm.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        heiko.carstens@...ibm.com, raspl@...ux.ibm.com,
        kgraul@...ux.ibm.com, ubraun@...ux.ibm.com
Subject: [PATCH net-next 6/6] net/smc: reduce port_event scheduling

IB event handlers schedule the port event worker for further
processing of port state changes. This patch reduces the number of
schedules to avoid duplicate processing of the same port change.

Reviewed-by: Karsten Graul <kgraul@...ux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@...ux.ibm.com>
---
 net/smc/smc_ib.c | 44 +++++++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 15 deletions(-)

diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index 548632621f4b..6756bd5a3fe4 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -257,6 +257,7 @@ static void smc_ib_global_event_handler(struct ib_event_handler *handler,
 					struct ib_event *ibevent)
 {
 	struct smc_ib_device *smcibdev;
+	bool schedule = false;
 	u8 port_idx;
 
 	smcibdev = container_of(handler, struct smc_ib_device, event_handler);
@@ -266,22 +267,35 @@ static void smc_ib_global_event_handler(struct ib_event_handler *handler,
 		/* terminate all ports on device */
 		for (port_idx = 0; port_idx < SMC_MAX_PORTS; port_idx++) {
 			set_bit(port_idx, &smcibdev->port_event_mask);
-			set_bit(port_idx, smcibdev->ports_going_away);
+			if (!test_and_set_bit(port_idx,
+					      smcibdev->ports_going_away))
+				schedule = true;
 		}
-		schedule_work(&smcibdev->port_event_work);
+		if (schedule)
+			schedule_work(&smcibdev->port_event_work);
 		break;
-	case IB_EVENT_PORT_ERR:
 	case IB_EVENT_PORT_ACTIVE:
-	case IB_EVENT_GID_CHANGE:
 		port_idx = ibevent->element.port_num - 1;
-		if (port_idx < SMC_MAX_PORTS) {
-			set_bit(port_idx, &smcibdev->port_event_mask);
-			if (ibevent->event == IB_EVENT_PORT_ERR)
-				set_bit(port_idx, smcibdev->ports_going_away);
-			else if (ibevent->event == IB_EVENT_PORT_ACTIVE)
-				clear_bit(port_idx, smcibdev->ports_going_away);
+		if (port_idx >= SMC_MAX_PORTS)
+			break;
+		set_bit(port_idx, &smcibdev->port_event_mask);
+		if (test_and_clear_bit(port_idx, smcibdev->ports_going_away))
+			schedule_work(&smcibdev->port_event_work);
+		break;
+	case IB_EVENT_PORT_ERR:
+		port_idx = ibevent->element.port_num - 1;
+		if (port_idx >= SMC_MAX_PORTS)
+			break;
+		set_bit(port_idx, &smcibdev->port_event_mask);
+		if (!test_and_set_bit(port_idx, smcibdev->ports_going_away))
 			schedule_work(&smcibdev->port_event_work);
-		}
+		break;
+	case IB_EVENT_GID_CHANGE:
+		port_idx = ibevent->element.port_num - 1;
+		if (port_idx >= SMC_MAX_PORTS)
+			break;
+		set_bit(port_idx, &smcibdev->port_event_mask);
+		schedule_work(&smcibdev->port_event_work);
 		break;
 	default:
 		break;
@@ -316,11 +330,11 @@ static void smc_ib_qp_event_handler(struct ib_event *ibevent, void *priv)
 	case IB_EVENT_QP_FATAL:
 	case IB_EVENT_QP_ACCESS_ERR:
 		port_idx = ibevent->element.qp->port - 1;
-		if (port_idx < SMC_MAX_PORTS) {
-			set_bit(port_idx, &smcibdev->port_event_mask);
-			set_bit(port_idx, smcibdev->ports_going_away);
+		if (port_idx >= SMC_MAX_PORTS)
+			break;
+		set_bit(port_idx, &smcibdev->port_event_mask);
+		if (!test_and_set_bit(port_idx, smcibdev->ports_going_away))
 			schedule_work(&smcibdev->port_event_work);
-		}
 		break;
 	default:
 		break;
-- 
2.17.1