[Intel-wired-lan] [PATCH net v2] i40e: Fix set max_tx_rate when it is lower than 1 Mbps

[Andrii Staikov]

From: Michal Jaron <michalx.jaron at intel.com>

Value max_tx_rate is converted from bytes to Mbps.
When max_tx_rate was set to lower than 125000 bytes (1 Mbps)
it was cut to 0 because of this conversion.

Add a check that if max_tx_rate is lower than 1 Mbps
set this to minimum usable value of 50 Mbps.

The visible behavior of it is following: "Setting max tx rate to minimum usable value of 50Mbps."

Add defined constants.

Fixes: 5ecae4120a6b ("i40e: Refactor VF BW rate limiting")
Signed-off-by: Michal Jaron <michalx.jaron at intel.com>
Signed-off-by: Andrii Staikov <andrii.staikov at intel.com>
---
 v2: Changing author, adding fixes tag, changing commit message.
---
 drivers/net/ethernet/intel/i40e/i40e_main.c | 32 +++++++++++++++++----
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 10c1e1ea83a1..e3d9804aeb25 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -5908,6 +5908,26 @@ static int i40e_get_link_speed(struct i40e_vsi *vsi)
 	}
 }
 
+/**
+ * i40e_bw_bytes_to_mbits - Convert max_tx_rate from bytes to mbits
+ * @vsi: Pointer to vsi structure
+ * @max_tx_rate: max TX rate in bytes to be converted into Mbits
+ *
+ * Helper function to convert units before send to set BW limit
+ **/
+static u64 i40e_bw_bytes_to_mbits(struct i40e_vsi *vsi, u64 max_tx_rate)
+{
+	if (max_tx_rate < I40E_BW_MBPS_DIVISOR) {
+		dev_warn(&vsi->back->pdev->dev,
+			 "Setting max tx rate to minimum usable value of 50Mbps.\n");
+		max_tx_rate = I40E_BW_CREDIT_DIVISOR;
+	} else {
+		do_div(max_tx_rate, I40E_BW_MBPS_DIVISOR);
+	}
+
+	return max_tx_rate;
+}
+
 /**
  * i40e_set_bw_limit - setup BW limit for Tx traffic based on max_tx_rate
  * @vsi: VSI to be configured
@@ -5930,10 +5950,10 @@ int i40e_set_bw_limit(struct i40e_vsi *vsi, u16 seid, u64 max_tx_rate)
 			max_tx_rate, seid);
 		return -EINVAL;
 	}
-	if (max_tx_rate && max_tx_rate < 50) {
+	if (max_tx_rate && max_tx_rate < I40E_BW_CREDIT_DIVISOR) {
 		dev_warn(&pf->pdev->dev,
 			 "Setting max tx rate to minimum usable value of 50Mbps.\n");
-		max_tx_rate = 50;
+		max_tx_rate = I40E_BW_CREDIT_DIVISOR;
 	}
 
 	/* Tx rate credits are in values of 50Mbps, 0 is disabled */
@@ -8224,9 +8244,9 @@ static int i40e_setup_tc(struct net_device *netdev, void *type_data)
 
 	if (i40e_is_tc_mqprio_enabled(pf)) {
 		if (vsi->mqprio_qopt.max_rate[0]) {
-			u64 max_tx_rate = vsi->mqprio_qopt.max_rate[0];
+			u64 max_tx_rate = i40e_bw_bytes_to_mbits(vsi,
+						  vsi->mqprio_qopt.max_rate[0]);
 
-			do_div(max_tx_rate, I40E_BW_MBPS_DIVISOR);
 			ret = i40e_set_bw_limit(vsi, vsi->seid, max_tx_rate);
 			if (!ret) {
 				u64 credits = max_tx_rate;
@@ -10971,10 +10991,10 @@ static void i40e_rebuild(struct i40e_pf *pf, bool reinit, bool lock_acquired)
 	}
 
 	if (vsi->mqprio_qopt.max_rate[0]) {
-		u64 max_tx_rate = vsi->mqprio_qopt.max_rate[0];
+		u64 max_tx_rate = i40e_bw_bytes_to_mbits(vsi,
+						  vsi->mqprio_qopt.max_rate[0]);
 		u64 credits = 0;
 
-		do_div(max_tx_rate, I40E_BW_MBPS_DIVISOR);
 		ret = i40e_set_bw_limit(vsi, vsi->seid, max_tx_rate);
 		if (ret)
 			goto end_unlock;
-- 
2.25.1