ixgbe: convert low_water into an array

Since fc.high_water is an array, we should treat low_water as an array
also. This allows the algorithm to output different values for different
TCs, and then we can distinguish between them. In addition, this patch
changes one path that didn't honor the return value from ixgbe_setup_fc.

Reported-by: Aaron Salter <aaron.k.salter@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 16 insertions, 11 deletions

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_82598.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_82598.c
index 4c78ea8946c1..1c52e4753480 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_82598.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_82598.c
@@ -337,19 +337,25 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw)
 	int i;
 	bool link_up;
 
-	/*
-	 * Validate the water mark configuration for packet buffer 0.  Zero
-	 * water marks indicate that the packet buffer was not configured
-	 * and the watermarks for packet buffer 0 should always be configured.
-	 */
-	if (!hw->fc.low_water ||
-	    !hw->fc.high_water[0] ||
-	    !hw->fc.pause_time) {
-		hw_dbg(hw, "Invalid water mark configuration\n");
+	/* Validate the water mark configuration */
+	if (!hw->fc.pause_time) {
 		ret_val = IXGBE_ERR_INVALID_LINK_SETTINGS;
 		goto out;
 	}
 
+	/* Low water mark of zero causes XOFF floods */
+	for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
+		if ((hw->fc.current_mode & ixgbe_fc_tx_pause) &&
+		    hw->fc.high_water[i]) {
+			if (!hw->fc.low_water[i] ||
+			    hw->fc.low_water[i] >= hw->fc.high_water[i]) {
+				hw_dbg(hw, "Invalid water mark configuration\n");
+				ret_val = IXGBE_ERR_INVALID_LINK_SETTINGS;
+				goto out;
+			}
+		}
+	}
+
 	/*
 	 * On 82598 having Rx FC on causes resets while doing 1G
 	 * so if it's on turn it off once we know link_speed. For
@@ -432,12 +438,11 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw)
 	IXGBE_WRITE_REG(hw, IXGBE_FCTRL, fctrl_reg);
 	IXGBE_WRITE_REG(hw, IXGBE_RMCS, rmcs_reg);
 
-	fcrtl = (hw->fc.low_water << 10) | IXGBE_FCRTL_XONE;
-
 	/* Set up and enable Rx high/low water mark thresholds, enable XON. */
 	for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
 		if ((hw->fc.current_mode & ixgbe_fc_tx_pause) &&
 		    hw->fc.high_water[i]) {
+			fcrtl = (hw->fc.low_water[i] << 10) | IXGBE_FCRTL_XONE;
 			fcrth = (hw->fc.high_water[i] << 10) | IXGBE_FCRTH_FCEN;
 			IXGBE_WRITE_REG(hw, IXGBE_FCRTL(i), fcrtl);
 			IXGBE_WRITE_REG(hw, IXGBE_FCRTH(i), fcrth);