Commit a7bf4d50 authored by Gal Pressman's avatar Gal Pressman Committed by Paolo Abeni
Browse files

net/mlx5e: Fix maxrate wraparound in threshold between units 



The previous calculation used roundup() which caused an overflow for
rates between 25.5Gbps and 26Gbps.
For example, a rate of 25.6Gbps would result in using 100Mbps units with
value of 256, which would overflow the 8 bits field.

Simplify the upper_limit_mbps calculation by removing the
unnecessary roundup, and adjust the comparison to use <= to correctly
handle the boundary condition.

Fixes: d8880795 ("net/mlx5e: Implement DCBNL IEEE max rate")
Signed-off-by: default avatarGal Pressman <gal@nvidia.com>
Reviewed-by: default avatarNimrod Oren <noren@nvidia.com>
Signed-off-by: default avatarTariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1762681073-1084058-4-git-send-email-tariqt@nvidia.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 2dc768c0

drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c

+3 −2
Original line number Diff line number Diff line
@@ -595,18 +595,19 @@ static int mlx5e_dcbnl_ieee_setmaxrate(struct net_device *netdev, 
	struct mlx5_core_dev *mdev = priv->mdev;

	u8 max_bw_value[IEEE_8021QAZ_MAX_TCS];

	u8 max_bw_unit[IEEE_8021QAZ_MAX_TCS];

	__u64 upper_limit_mbps = roundup(255 * MLX5E_100MB, MLX5E_1GB);

	__u64 upper_limit_mbps;

	int i;



	memset(max_bw_value, 0, sizeof(max_bw_value));

	memset(max_bw_unit, 0, sizeof(max_bw_unit));

	upper_limit_mbps = 255 * MLX5E_100MB;



	for (i = 0; i <= mlx5_max_tc(mdev); i++) {

		if (!maxrate->tc_maxrate[i]) {

			max_bw_unit[i]  = MLX5_BW_NO_LIMIT;

			continue;

		}

		if (maxrate->tc_maxrate[i] < upper_limit_mbps) {

		if (maxrate->tc_maxrate[i] <= upper_limit_mbps) {

			max_bw_value[i] = div_u64(maxrate->tc_maxrate[i],

						  MLX5E_100MB);

			max_bw_value[i] = max_bw_value[i] ? max_bw_value[i] : 1;