ice: fix changing of ring descriptor size (ethtool -G)

rx_mini_pending was set to an incorrect value. This was causing EINVAL to
always be returned to 'ethtool -G'. The driver does not support mini or
jumbo rings so the respective settings should be zero.

Also, change the valid range of the number of descriptors in the rings to
make the code simpler and easier for users to understand (this removes the
valid settings of 8 and 16). Add a system log message indicating when the
number is rounded-up from what the user specifies with the 'ethtool -G'
command (i.e. when it is not a multiple of 32), and update the log message
when a user-provided value is out of range to also indicate the stride.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ice/ice.h

@@ -39,9 +39,9 @@
 extern const char ice_drv_ver[];
 #define ICE_BAR0		0
 #define ICE_DFLT_NUM_DESC	128
-#define ICE_MIN_NUM_DESC	8
-#define ICE_MAX_NUM_DESC	8160
 #define ICE_REQ_DESC_MULTIPLE	32
+#define ICE_MIN_NUM_DESC	ICE_REQ_DESC_MULTIPLE
+#define ICE_MAX_NUM_DESC	8160
 #define ICE_DFLT_TRAFFIC_CLASS	BIT(0)
 #define ICE_INT_NAME_STR_LEN	(IFNAMSIZ + 16)
 #define ICE_ETHTOOL_FWVER_LEN	32

drivers/net/ethernet/intel/ice/ice_ethtool.c

@@ -1198,9 +1198,11 @@ ice_get_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring)
 	ring->tx_max_pending = ICE_MAX_NUM_DESC;
 	ring->rx_pending = vsi->rx_rings[0]->count;
 	ring->tx_pending = vsi->tx_rings[0]->count;
-	ring->rx_mini_pending = ICE_MIN_NUM_DESC;
+
+	/* Rx mini and jumbo rings are not supported */
 	ring->rx_mini_max_pending = 0;
 	ring->rx_jumbo_max_pending = 0;
+	ring->rx_mini_pending = 0;
 	ring->rx_jumbo_pending = 0;
 }
 
@@ -1218,14 +1220,23 @@ ice_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring)
 	    ring->tx_pending < ICE_MIN_NUM_DESC ||
 	    ring->rx_pending > ICE_MAX_NUM_DESC ||
 	    ring->rx_pending < ICE_MIN_NUM_DESC) {
-		netdev_err(netdev, "Descriptors requested (Tx: %d / Rx: %d) out of range [%d-%d]\n",
+		netdev_err(netdev, "Descriptors requested (Tx: %d / Rx: %d) out of range [%d-%d] (increment %d)\n",
 			   ring->tx_pending, ring->rx_pending,
-			   ICE_MIN_NUM_DESC, ICE_MAX_NUM_DESC);
+			   ICE_MIN_NUM_DESC, ICE_MAX_NUM_DESC,
+			   ICE_REQ_DESC_MULTIPLE);
 		return -EINVAL;
 	}
 
 	new_tx_cnt = ALIGN(ring->tx_pending, ICE_REQ_DESC_MULTIPLE);
+	if (new_tx_cnt != ring->tx_pending)
+		netdev_info(netdev,
+			    "Requested Tx descriptor count rounded up to %d\n",
+			    new_tx_cnt);
 	new_rx_cnt = ALIGN(ring->rx_pending, ICE_REQ_DESC_MULTIPLE);
+	if (new_rx_cnt != ring->rx_pending)
+		netdev_info(netdev,
+			    "Requested Rx descriptor count rounded up to %d\n",
+			    new_rx_cnt);
 
 	/* if nothing to do return success */
 	if (new_tx_cnt == vsi->tx_rings[0]->count &&