e1000e: re-factor ethtool get/set ring parameter

Make it more like how igb does it, with some additional error checking.
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e1000e/ethtool.c

@@ -605,94 +605,112 @@ static void e1000_get_ringparam(struct net_device *netdev,
 				struct ethtool_ringparam *ring)
 {
 	struct e1000_adapter *adapter = netdev_priv(netdev);
-	struct e1000_ring *tx_ring = adapter->tx_ring;
-	struct e1000_ring *rx_ring = adapter->rx_ring;
 
 	ring->rx_max_pending = E1000_MAX_RXD;
 	ring->tx_max_pending = E1000_MAX_TXD;
-	ring->rx_pending = rx_ring->count;
-	ring->tx_pending = tx_ring->count;
+	ring->rx_pending = adapter->rx_ring_count;
+	ring->tx_pending = adapter->tx_ring_count;
 }
 
 static int e1000_set_ringparam(struct net_device *netdev,
 			       struct ethtool_ringparam *ring)
 {
 	struct e1000_adapter *adapter = netdev_priv(netdev);
-	struct e1000_ring *tx_ring, *tx_old;
-	struct e1000_ring *rx_ring, *rx_old;
-	int err;
+	struct e1000_ring *temp_tx = NULL, *temp_rx = NULL;
+	int err = 0, size = sizeof(struct e1000_ring);
+	bool set_tx = false, set_rx = false;
+	u16 new_rx_count, new_tx_count;
 
 	if ((ring->rx_mini_pending) || (ring->rx_jumbo_pending))
 		return -EINVAL;
 
-	while (test_and_set_bit(__E1000_RESETTING, &adapter->state))
-		usleep_range(1000, 2000);
+	new_rx_count = clamp_t(u32, ring->rx_pending, E1000_MIN_RXD,
+			       E1000_MAX_RXD);
+	new_rx_count = ALIGN(new_rx_count, REQ_RX_DESCRIPTOR_MULTIPLE);
 
-	if (netif_running(adapter->netdev))
-		e1000e_down(adapter);
+	new_tx_count = clamp_t(u32, ring->tx_pending, E1000_MIN_TXD,
+			       E1000_MAX_TXD);
+	new_tx_count = ALIGN(new_tx_count, REQ_TX_DESCRIPTOR_MULTIPLE);
 
-	tx_old = adapter->tx_ring;
-	rx_old = adapter->rx_ring;
+	if ((new_tx_count == adapter->tx_ring_count) &&
+	    (new_rx_count == adapter->rx_ring_count))
+		/* nothing to do */
+		return 0;
 
-	err = -ENOMEM;
-	tx_ring = kmemdup(tx_old, sizeof(struct e1000_ring), GFP_KERNEL);
-	if (!tx_ring)
-		goto err_alloc_tx;
+	while (test_and_set_bit(__E1000_RESETTING, &adapter->state))
+		usleep_range(1000, 2000);
 
-	rx_ring = kmemdup(rx_old, sizeof(struct e1000_ring), GFP_KERNEL);
-	if (!rx_ring)
-		goto err_alloc_rx;
+	if (!netif_running(adapter->netdev)) {
+		/* Set counts now and allocate resources during open() */
+		adapter->tx_ring->count = new_tx_count;
+		adapter->rx_ring->count = new_rx_count;
+		adapter->tx_ring_count = new_tx_count;
+		adapter->rx_ring_count = new_rx_count;
+		goto clear_reset;
+	}
 
-	adapter->tx_ring = tx_ring;
-	adapter->rx_ring = rx_ring;
+	set_tx = (new_tx_count != adapter->tx_ring_count);
+	set_rx = (new_rx_count != adapter->rx_ring_count);
 
-	rx_ring->count = max(ring->rx_pending, (u32)E1000_MIN_RXD);
-	rx_ring->count = min(rx_ring->count, (u32)(E1000_MAX_RXD));
-	rx_ring->count = ALIGN(rx_ring->count, REQ_RX_DESCRIPTOR_MULTIPLE);
+	/* Allocate temporary storage for ring updates */
+	if (set_tx) {
+		temp_tx = vmalloc(size);
+		if (!temp_tx) {
+			err = -ENOMEM;
+			goto free_temp;
+		}
+	}
+	if (set_rx) {
+		temp_rx = vmalloc(size);
+		if (!temp_rx) {
+			err = -ENOMEM;
+			goto free_temp;
+		}
+	}
 
-	tx_ring->count = max(ring->tx_pending, (u32)E1000_MIN_TXD);
-	tx_ring->count = min(tx_ring->count, (u32)(E1000_MAX_TXD));
-	tx_ring->count = ALIGN(tx_ring->count, REQ_TX_DESCRIPTOR_MULTIPLE);
+	e1000e_down(adapter);
 
-	if (netif_running(adapter->netdev)) {
-		/* Try to get new resources before deleting old */
-		err = e1000e_setup_rx_resources(rx_ring);
+	/*
+	 * We can't just free everything and then setup again, because the
+	 * ISRs in MSI-X mode get passed pointers to the Tx and Rx ring
+	 * structs.  First, attempt to allocate new resources...
+	 */
+	if (set_tx) {
+		memcpy(temp_tx, adapter->tx_ring, size);
+		temp_tx->count = new_tx_count;
+		err = e1000e_setup_tx_resources(temp_tx);
 		if (err)
-			goto err_setup_rx;
-		err = e1000e_setup_tx_resources(tx_ring);
+			goto err_setup;
+	}
+	if (set_rx) {
+		memcpy(temp_rx, adapter->rx_ring, size);
+		temp_rx->count = new_rx_count;
+		err = e1000e_setup_rx_resources(temp_rx);
 		if (err)
-			goto err_setup_tx;
+			goto err_setup_rx;
+	}
 
-		/*
-		 * restore the old in order to free it,
-		 * then add in the new
-		 */
-		adapter->rx_ring = rx_old;
-		adapter->tx_ring = tx_old;
-		e1000e_free_rx_resources(adapter->rx_ring);
+	/* ...then free the old resources and copy back any new ring data */
+	if (set_tx) {
 		e1000e_free_tx_resources(adapter->tx_ring);
-		kfree(tx_old);
-		kfree(rx_old);
-		adapter->rx_ring = rx_ring;
-		adapter->tx_ring = tx_ring;
-		err = e1000e_up(adapter);
-		if (err)
-			goto err_setup;
+		memcpy(adapter->tx_ring, temp_tx, size);
+		adapter->tx_ring_count = new_tx_count;
+	}
+	if (set_rx) {
+		e1000e_free_rx_resources(adapter->rx_ring);
+		memcpy(adapter->rx_ring, temp_rx, size);
+		adapter->rx_ring_count = new_rx_count;
 	}
 
-	clear_bit(__E1000_RESETTING, &adapter->state);
-	return 0;
-err_setup_tx:
-	e1000e_free_rx_resources(rx_ring);
 err_setup_rx:
-	adapter->rx_ring = rx_old;
-	adapter->tx_ring = tx_old;
-	kfree(rx_ring);
-err_alloc_rx:
-	kfree(tx_ring);
-err_alloc_tx:
-	e1000e_up(adapter);
+	if (err && set_tx)
+		e1000e_free_tx_resources(temp_tx);
 err_setup:
+	e1000e_up(adapter);
+free_temp:
+	vfree(temp_tx);
+	vfree(temp_rx);
+clear_reset:
 	clear_bit(__E1000_RESETTING, &adapter->state);
 	return err;
 }