tg3: extract GRXRINGS from .get_rxnfc

Commit 84eaf4359c36 ("net: ethtool: add get_rx_ring_count callback to
optimize RX ring queries") added specific support for GRXRINGS callback,
simplifying .get_rxnfc.

Remove the handling of GRXRINGS in .get_rxnfc() by moving it to the new
.get_rx_ring_count().

Given that tg3_get_rxnfc() only handles ETHTOOL_GRXRINGS, then this
function becomes useless now, and it is removed.

This also fixes the behavior for devices without MSIX support.
Previously, the function would return -EOPNOTSUPP, but now it correctly
returns 1.

The functionality remains the same: return the current queue count
if the device is running, otherwise return the minimum of online
CPUs and TG3_RSS_MAX_NUM_QS.

Signed-off-by: Breno Leitao <[e-mail]>
Reviewed-by: Michael Chan <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/broadcom/tg3.c

···
 	}
 }
 
-static int tg3_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info,
-			 u32 *rules __always_unused)
+static u32 tg3_get_rx_ring_count(struct net_device *dev)
 {
 	struct tg3 *tp = netdev_priv(dev);
 
 	if (!tg3_flag(tp, SUPPORT_MSIX))
-		return -EOPNOTSUPP;
+		return 1;
 
-	switch (info->cmd) {
-	case ETHTOOL_GRXRINGS:
-		if (netif_running(tp->dev))
-			info->data = tp->rxq_cnt;
-		else {
-			info->data = num_online_cpus();
-			if (info->data > TG3_RSS_MAX_NUM_QS)
-				info->data = TG3_RSS_MAX_NUM_QS;
-		}
+	if (netif_running(tp->dev))
+		return tp->rxq_cnt;
 
-		return 0;
-
-	default:
-		return -EOPNOTSUPP;
-	}
+	return min(num_online_cpus(), TG3_RSS_MAX_NUM_QS);
 }
 
 static u32 tg3_get_rxfh_indir_size(struct net_device *dev)
···
 	.get_coalesce		= tg3_get_coalesce,
 	.set_coalesce		= tg3_set_coalesce,
 	.get_sset_count		= tg3_get_sset_count,
-	.get_rxnfc		= tg3_get_rxnfc,
+	.get_rx_ring_count	= tg3_get_rx_ring_count,
 	.get_rxfh_indir_size    = tg3_get_rxfh_indir_size,
 	.get_rxfh		= tg3_get_rxfh,
 	.set_rxfh		= tg3_set_rxfh,