Query the link status can end up in an inconsist state where the port is
down but it is reporting speed. For that another query is scheduled for a
later time.
A race condition is possible between the scheduled call and other link
status interrupt handlers. When the scheduled query by-pass those handlers,
the link status will be stuck in an in-consist state.
This patch addresses the race condition by not blocking link status
queries in case delayed query is on the flight.
Fixes: 198a3c339a8f ("mlx5: handle link status interrupts")
CC: sta...@dpdk.org
Signed-off-by: Shahaf Shuler <shah...@mellanox.com>
---
on v3:
* allow only single alarm on the flight.
on v2:
* change the commit log to better explain the race
* instead of blocking other interrupt handlers allow everyone to query the link
status
---
drivers/net/mlx5/mlx5_ethdev.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)
diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
index e77238f..fcbe273 100644
--- a/drivers/net/mlx5/mlx5_ethdev.c
+++ b/drivers/net/mlx5/mlx5_ethdev.c
@@ -1128,7 +1128,7 @@ struct priv *
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. */
@@ -1136,29 +1136,24 @@ struct priv *
if (ibv_get_async_event(priv->ctx, &event))
break;
- if (event.event_type == IBV_EVENT_PORT_ACTIVE ||
- event.event_type == IBV_EVENT_PORT_ERR)
- port_change = 1;
- else
+ if (event.event_type != IBV_EVENT_PORT_ACTIVE &&
+ event.event_type != IBV_EVENT_PORT_ERR)
DEBUG("event type %d on port %d not handled",
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;
- mlx5_link_update(dev, 0);
- if (((link->link_speed == 0) && link->link_status) ||
- ((link->link_speed != 0) && !link->link_status)) {
+ mlx5_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(MLX5_ALARM_TIMEOUT_US,
mlx5_dev_link_status_handler,
dev);
- } else
- ret = 1;
+ }
+ } else {
+ ret = 1;
}
return ret;
}
@@ -1178,6 +1173,7 @@ struct priv *
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)
--
1.8.3.1
