RXQ interrupts under Linux are based on the epoll mechanism. An
expected order of operations is as follows:
1. Call rte_eth_dev_rx_intr_enable(), to arm the CQ for receiving events
on data input.
2. Block on rte_epoll_wait() with an array of file descriptors
representing the CQ events. Upon data arrival the kernel will signal an
input event on the corresponding CQ fd.
3. Call rte_eth_dev_rx_intr_disable() after the event was received and
continue in polling mode. The mlx5 implementation of
rte_eth_dev_rx_intr_disable() is to get the CQ event and ack it.
In practice applications may wake up from rte_epoll_wait() due to
timeout with no event to ack but still call
rte_eth_dev_rx_intr_disable() unconditionally. In such cases the call
should return EAGAIN (since the file descriptors are non-blocked), as
opposed to EINVAL which indicates a real failure. In case of EAGAIN the
PMD should not warn on "Unable to disable interrupt on Rx queue".
Signed-off-by: Ophir Munk <ophi...@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viachesl...@mellanox.com>
---
drivers/net/mlx5/mlx5_rxq.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index b436f06..38dfb98 100644
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -936,7 +936,14 @@ mlx5_rx_intr_disable(struct rte_eth_dev *dev, uint16_t
rx_queue_id)
}
ret = mlx5_glue->get_cq_event(rxq_obj->channel, &ev_cq, &ev_ctx);
if (ret || ev_cq != rxq_obj->cq) {
- rte_errno = EINVAL;
+ /**
+ * For non-zero 'ret' - save the errno (may be EAGAIN which
+ * means this function was called before receiving an event).
+ */
+ if (ret)
+ rte_errno = errno;
+ else
+ rte_errno = EINVAL;
goto exit;
}
rxq_data->cq_arm_sn++;
@@ -947,8 +954,9 @@ mlx5_rx_intr_disable(struct rte_eth_dev *dev, uint16_t
rx_queue_id)
ret = rte_errno; /* Save rte_errno before cleanup. */
if (rxq_obj)
mlx5_rxq_obj_release(rxq_obj);
- DRV_LOG(WARNING, "port %u unable to disable interrupt on Rx queue %d",
- dev->data->port_id, rx_queue_id);
+ if (ret != EAGAIN)
+ DRV_LOG(WARNING, "port %u unable to disable interrupt on Rx
queue %d",
+ dev->data->port_id, rx_queue_id);
rte_errno = ret; /* Restore rte_errno. */
return -rte_errno;
}
--
2.8.4
