bnxt_en: Fix ethtool -l|-L inconsistent channel counts.

The existing code is inconsistent in reporting and accepting the combined
channel count.  bnxt_get_channels() reports maximum combined as the
maximum rx count.  bnxt_set_channels() accepts combined count that
cannot be bigger than max rx or max tx.

For example, if max rx = 2 and max tx = 1, we report max supported
combined to be 2.  But if the user tries to set combined to 2, it will
fail because 2 is bigger than max tx which is 1.

Fix the code to be consistent.  Max allowed combined = max(max_rx, max_tx).
We will accept a combined channel count <= max(max_rx, max_tx).

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -348,7 +348,7 @@ static void bnxt_get_channels(struct net_device *dev,
 	int max_rx_rings, max_tx_rings, tcs;
 
 	bnxt_get_max_rings(bp, &max_rx_rings, &max_tx_rings, true);
-	channel->max_combined = max_rx_rings;
+	channel->max_combined = max_t(int, max_rx_rings, max_tx_rings);
 
 	if (bnxt_get_max_rings(bp, &max_rx_rings, &max_tx_rings, false)) {
 		max_rx_rings = 0;
@@ -406,8 +406,8 @@ static int bnxt_set_channels(struct net_device *dev,
 	if (tcs > 1)
 		max_tx_rings /= tcs;
 
-	if (sh && (channel->combined_count > max_rx_rings ||
-		   channel->combined_count > max_tx_rings))
+	if (sh &&
+	    channel->combined_count > max_t(int, max_rx_rings, max_tx_rings))
 		return -ENOMEM;
 
 	if (!sh && (channel->rx_count > max_rx_rings ||
@@ -430,8 +430,10 @@ static int bnxt_set_channels(struct net_device *dev,
 
 	if (sh) {
 		bp->flags |= BNXT_FLAG_SHARED_RINGS;
-		bp->rx_nr_rings = channel->combined_count;
-		bp->tx_nr_rings_per_tc = channel->combined_count;
+		bp->rx_nr_rings = min_t(int, channel->combined_count,
+					max_rx_rings);
+		bp->tx_nr_rings_per_tc = min_t(int, channel->combined_count,
+					       max_tx_rings);
 	} else {
 		bp->flags &= ~BNXT_FLAG_SHARED_RINGS;
 		bp->rx_nr_rings = channel->rx_count;