d/numam-dpdk
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

net/mlx4: fix premature disabling of interrupt

Browse Source 
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 mlx4 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 <ophirmu@mellanox.com>
Acked-by: Raslan Darawsheh <rasland@mellanox.com>
This commit is contained in:
Ophir Munk 2020-07-28 11:54:06 +00:00 committed by Ferruh Yigit
parent d7964ce192
commit 54b20f94cd
1 changed files with 10 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/net/mlx4/mlx4_intr.c
View File

@ -326,13 +326,20 @@ mlx4_rx_intr_disable(struct rte_eth_dev *dev, uint16_t idx)
} else {
ret = mlx4_glue->get_cq_event(rxq->cq->channel, &ev_cq,
&ev_ctx);
if (ret || ev_cq != rxq->cq)
/** For non-zero ret save the errno (may be EAGAIN
* which means the get_cq_event function was called before
* receiving one).
*/
if (ret)
ret = errno;
else if (ev_cq != rxq->cq)
ret = EINVAL;
}
if (ret) {
rte_errno = ret;
WARN("unable to disable interrupt on rx queue %d",
idx);
if (ret != EAGAIN)
WARN("unable to disable interrupt on rx queue %d",
idx);
} else {
rxq->mcq.arm_sn++;
mlx4_glue->ack_cq_events(rxq->cq, 1);