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net/mlx5: fix premature disabling of interrupt

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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".

This commit fixes a earlier commit where the returned value 0 from
function devx_get_event() - was considered an error.

Fixes: 08d1838f645a ("net/mlx5: implement CQ for Rx using DevX API")

Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Raslan Darawsheh <rasland@mellanox.com>
This commit is contained in:
Ophir Munk 2020-07-21 14:41:07 +00:00 committed by Ferruh Yigit
parent f0585e8559
commit 385c19397e
1 changed files with 14 additions and 9 deletions
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23
drivers/net/mlx5/mlx5_rxq.c
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@ -1188,10 +1188,8 @@ mlx5_rx_intr_disable(struct rte_eth_dev *dev, uint16_t rx_queue_id)
if (rxq_obj->type == MLX5_RXQ_OBJ_TYPE_IBV) {
ret = mlx5_glue->get_cq_event(rxq_obj->ibv_channel, &ev_cq,
&ev_ctx);
if (ret || ev_cq != rxq_obj->ibv_cq) {
rte_errno = EINVAL;
if (ret < 0 || ev_cq != rxq_obj->ibv_cq)
goto exit;
}
mlx5_glue->ack_cq_events(rxq_obj->ibv_cq, 1);
} else if (rxq_obj->type == MLX5_RXQ_OBJ_TYPE_DEVX_RQ) {
#ifdef HAVE_IBV_DEVX_EVENT
@ -1200,22 +1198,29 @@ mlx5_rx_intr_disable(struct rte_eth_dev *dev, uint16_t rx_queue_id)
ret = mlx5_glue->devx_get_event
(rxq_obj->devx_channel, event_data,
sizeof(struct mlx5dv_devx_async_event_hdr));
if (ret <= 0 || event_data->cookie !=
(uint64_t)(uintptr_t)rxq_obj->devx_cq) {
rte_errno = EINVAL;
if (ret < 0 || event_data->cookie !=
(uint64_t)(uintptr_t)rxq_obj->devx_cq)
goto exit;
}
#endif /* HAVE_IBV_DEVX_EVENT */
}
rxq_data->cq_arm_sn++;
mlx5_rxq_obj_release(rxq_obj);
return 0;
exit:
/**
* For ret < 0 save the errno (may be EAGAIN which means the get_event
* function was called before receiving one).
*/
if (ret < 0)
rte_errno = errno;
else
rte_errno = EINVAL;
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;
}