Commit ae3cb71e authored by Gal Pressman's avatar Gal Pressman Committed by Jakub Kicinski
Browse files

net/mlx5e: Fix misidentification of ASO CQE during poll loop 



The ASO completion poll loop uses usleep_range() which can sleep much
longer than requested due to scheduler latency. Under load, we witnessed
a 20ms+ delay until the process was rescheduled, causing the jiffies
based timeout to expire while the thread is sleeping.

The original do-while loop structure (poll, sleep, check timeout) would
exit without a final poll when waking after timeout, missing a CQE that
arrived during sleep.

Instead of the open-coded while loop, use the kernel's
read_poll_timeout() which always performs an additional check after the
sleep expiration, and is less error-prone.

Note: read_poll_timeout() doesn't accept a sleep range, by passing 10
sleep_us the sleep range effectively changes from 2-10 to 3-10 usecs.

Fixes: 739cfa34 ("net/mlx5: Make ASO poll CQ usable in atomic context")
Fixes: 7e3fce82 ("net/mlx5e: Overcome slow response for first macsec ASO WQE")
Signed-off-by: default avatarGal Pressman <gal@nvidia.com>
Reviewed-by: default avatarJianbo Liu <jianbol@nvidia.com>
Signed-off-by: default avatarTariq Toukan <tariqt@nvidia.com>
Reviewed-by: default avatarJacob Keller <Jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260218072904.1764634-3-tariqt@nvidia.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 47bf2e81

drivers/net/ethernet/mellanox/mlx5/core/en/tc/meter.c

+3 −7
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB

// Copyright (c) 2021, NVIDIA CORPORATION & AFFILIATES. All rights reserved.



#include <linux/iopoll.h>

#include <linux/math64.h>

#include "lib/aso.h"

#include "en/tc/post_act.h"
@@ -115,7 +116,6 @@ mlx5e_tc_meter_modify(struct mlx5_core_dev *mdev, 
	struct mlx5e_flow_meters *flow_meters;

	u8 cir_man, cir_exp, cbs_man, cbs_exp;

	struct mlx5_aso_wqe *aso_wqe;

	unsigned long expires;

	struct mlx5_aso *aso;

	u64 rate, burst;

	u8 ds_cnt;
@@ -187,12 +187,8 @@ mlx5e_tc_meter_modify(struct mlx5_core_dev *mdev, 
	mlx5_aso_post_wqe(aso, true, &aso_wqe->ctrl);



	/* With newer FW, the wait for the first ASO WQE is more than 2us, put the wait 10ms. */

	expires = jiffies + msecs_to_jiffies(10);

	do {

		err = mlx5_aso_poll_cq(aso, true);

		if (err)

			usleep_range(2, 10);

	} while (err && time_is_after_jiffies(expires));

	read_poll_timeout(mlx5_aso_poll_cq, err, !err, 10, 10 * USEC_PER_MSEC,

			  false, aso, true);

	mutex_unlock(&flow_meters->aso_lock);



	return err;

drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c

+3 −7
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <linux/mlx5/mlx5_ifc.h>

#include <linux/xarray.h>

#include <linux/if_vlan.h>

#include <linux/iopoll.h>



#include "en.h"

#include "lib/aso.h"
@@ -1397,7 +1398,6 @@ static int macsec_aso_query(struct mlx5_core_dev *mdev, struct mlx5e_macsec *mac 
	struct mlx5e_macsec_aso *aso;

	struct mlx5_aso_wqe *aso_wqe;

	struct mlx5_aso *maso;

	unsigned long expires;

	int err;



	aso = &macsec->aso;
@@ -1411,12 +1411,8 @@ static int macsec_aso_query(struct mlx5_core_dev *mdev, struct mlx5e_macsec *mac 
	macsec_aso_build_wqe_ctrl_seg(aso, &aso_wqe->aso_ctrl, NULL);



	mlx5_aso_post_wqe(maso, false, &aso_wqe->ctrl);

	expires = jiffies + msecs_to_jiffies(10);

	do {

		err = mlx5_aso_poll_cq(maso, false);

		if (err)

			usleep_range(2, 10);

	} while (err && time_is_after_jiffies(expires));

	read_poll_timeout(mlx5_aso_poll_cq, err, !err, 10, 10 * USEC_PER_MSEC,

			  false, maso, false);



	if (err)

		goto err_out;