[PATCH 5.4 49/61] net/mlx5e: E-switch, Fix rate calculation for overflow

[Greg Kroah-Hartman]

From: Parav Pandit <parav@xxxxxxxxxx>

[ Upstream commit 1fe3e3166b35240615ab7f8276af2bbf2e51f559 ]

rate_bytes_ps is a 64-bit field. It passed as 32-bit field to
apply_police_params(). Due to this when police rate is higher
than 4Gbps, 32-bit calculation ignores the carry. This results
in incorrect rate configurationn the device.

Fix it by performing 64-bit calculation.

Fixes: fcb64c0f5640 ("net/mlx5: E-Switch, add ingress rate support")
Signed-off-by: Parav Pandit <parav@xxxxxxxxxx>
Reviewed-by: Eli Cohen <elic@xxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index ec117e4414250..37051a4820a08 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -57,6 +57,7 @@
 #include "lib/devcom.h"
 #include "lib/geneve.h"
 #include "diag/en_tc_tracepoint.h"
+#include <asm/div64.h>
 
 struct mlx5_nic_flow_attr {
 	u32 action;
@@ -3943,13 +3944,13 @@ errout:
 	return err;
 }
 
-static int apply_police_params(struct mlx5e_priv *priv, u32 rate,
+static int apply_police_params(struct mlx5e_priv *priv, u64 rate,
 			       struct netlink_ext_ack *extack)
 {
 	struct mlx5e_rep_priv *rpriv = priv->ppriv;
 	struct mlx5_eswitch *esw;
+	u32 rate_mbps = 0;
 	u16 vport_num;
-	u32 rate_mbps;
 	int err;
 
 	vport_num = rpriv->rep->vport;
@@ -3966,7 +3967,11 @@ static int apply_police_params(struct mlx5e_priv *priv, u32 rate,
 	 * Moreover, if rate is non zero we choose to configure to a minimum of
 	 * 1 mbit/sec.
 	 */
-	rate_mbps = rate ? max_t(u32, (rate * 8 + 500000) / 1000000, 1) : 0;
+	if (rate) {
+		rate = (rate * BITS_PER_BYTE) + 500000;
+		rate_mbps = max_t(u32, do_div(rate, 1000000), 1);
+	}
+
 	err = mlx5_esw_modify_vport_rate(esw, vport_num, rate_mbps);
 	if (err)
 		NL_SET_ERR_MSG_MOD(extack, "failed applying action to hardware");
-- 
2.27.0