[dpdk-stable] [PATCH 2/2] net/mlx4: fix assertion failure on link update

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

[ backported from upstream commit 2d449f7c52de93a5978b03ea541e454fe87f801b ]

The interrupt handler can sometimes be triggered for reasons other than a
link status event. An assertion failure happen when such events occur while
an asynchronous link status update is already scheduled.

Address this issue using the same approach as its mlx5 counterpart,
commit a9f2fbc42f0c ("net/mlx5: fix inconsistent link status")

Fixes: c4da6caa426d ("mlx4: handle link status interrupts")
Cc: stable@dpdk.org

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Acked-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
---
 drivers/net/mlx4/mlx4.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index 22af742..e17d371 100644
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c
@@ -5386,6 +5386,7 @@ priv_dev_link_status_handler(struct priv *priv, struct rte_eth_dev *dev)
 {
 	struct ibv_async_event event;
 	int port_change = 0;
+	struct rte_eth_link *link = &dev->data->dev_link;
 	int ret = 0;
 
 	/* Read all message and acknowledge them. */
@@ -5401,21 +5402,20 @@ priv_dev_link_status_handler(struct priv *priv, struct rte_eth_dev *dev)
 			      event.event_type, event.element.port_num);
 		ibv_ack_async_event(&event);
 	}
-
-	if (port_change ^ priv->pending_alarm) {
-		struct rte_eth_link *link = &dev->data->dev_link;
-
-		priv->pending_alarm = 0;
-		mlx4_link_update(dev, 0);
-		if (((link->link_speed == 0) && link->link_status) ||
-		    ((link->link_speed != 0) && !link->link_status)) {
+	if (!port_change)
+		return ret;
+	mlx4_link_update(dev, 0);
+	if (((link->link_speed == 0) && link->link_status) ||
+	    ((link->link_speed != 0) && !link->link_status)) {
+		if (!priv->pending_alarm) {
 			/* Inconsistent status, check again later. */
 			priv->pending_alarm = 1;
 			rte_eal_alarm_set(MLX4_ALARM_TIMEOUT_US,
 					  mlx4_dev_link_status_handler,
 					  dev);
-		} else
-			ret = 1;
+		}
+	} else {
+		ret = 1;
 	}
 	return ret;
 }
@@ -5435,6 +5435,7 @@ mlx4_dev_link_status_handler(void *arg)
 
 	priv_lock(priv);
 	assert(priv->pending_alarm == 1);
+	priv->pending_alarm = 0;
 	ret = priv_dev_link_status_handler(priv, dev);
 	priv_unlock(priv);
 	if (ret)
-- 
2.1.4