alx: refactor descriptor allocation

Split the allocation of descriptor memory and the buffer allocation into a
tx and rx function. This is in preparation for multiple queues where we
need to iterate over the new functions.

While at it drop the unneeded casting on the rx side.

Signed-off-by: Tobias Regnery <tobias.regnery@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/atheros/alx/main.c

@@ -573,19 +573,41 @@ static int alx_set_mac_address(struct net_device *netdev, void *data)
 	return 0;
 }
 
-static int alx_alloc_descriptors(struct alx_priv *alx)
+static int alx_alloc_tx_ring(struct alx_priv *alx, struct alx_tx_queue *txq,
+			     int offset)
 {
-	alx->txq.bufs = kcalloc(alx->tx_ringsz,
-				sizeof(struct alx_buffer),
-				GFP_KERNEL);
-	if (!alx->txq.bufs)
+	txq->bufs = kcalloc(alx->tx_ringsz, sizeof(struct alx_buffer), GFP_KERNEL);
+	if (!txq->bufs)
 		return -ENOMEM;
 
-	alx->rxq.bufs = kcalloc(alx->rx_ringsz,
-				sizeof(struct alx_buffer),
-				GFP_KERNEL);
-	if (!alx->rxq.bufs)
-		goto out_free;
+	txq->tpd = alx->descmem.virt + offset;
+	txq->tpd_dma = alx->descmem.dma + offset;
+	offset += sizeof(struct alx_txd) * alx->tx_ringsz;
+
+	return offset;
+}
+
+static int alx_alloc_rx_ring(struct alx_priv *alx, struct alx_rx_queue *rxq,
+			     int offset)
+{
+	rxq->bufs = kcalloc(alx->rx_ringsz, sizeof(struct alx_buffer), GFP_KERNEL);
+	if (!rxq->bufs)
+		return -ENOMEM;
+
+	rxq->rrd = alx->descmem.virt + offset;
+	rxq->rrd_dma = alx->descmem.dma + offset;
+	offset += sizeof(struct alx_rrd) * alx->rx_ringsz;
+
+	rxq->rfd = alx->descmem.virt + offset;
+	rxq->rfd_dma = alx->descmem.dma + offset;
+	offset += sizeof(struct alx_rfd) * alx->rx_ringsz;
+
+	return offset;
+}
+
+static int alx_alloc_rings(struct alx_priv *alx)
+{
+	int offset = 0;
 
 	/* physical tx/rx ring descriptors
 	 *
@@ -601,45 +623,23 @@ static int alx_alloc_descriptors(struct alx_priv *alx)
 						&alx->descmem.dma,
 						GFP_KERNEL);
 	if (!alx->descmem.virt)
-		goto out_free;
-
-	alx->txq.tpd = alx->descmem.virt;
-	alx->txq.tpd_dma = alx->descmem.dma;
+		return -ENOMEM;
 
-	/* alignment requirement for next block */
+	/* alignment requirements */
 	BUILD_BUG_ON(sizeof(struct alx_txd) % 8);
-
-	alx->rxq.rrd =
-		(void *)((u8 *)alx->descmem.virt +
-			 sizeof(struct alx_txd) * alx->tx_ringsz);
-	alx->rxq.rrd_dma = alx->descmem.dma +
-			   sizeof(struct alx_txd) * alx->tx_ringsz;
-
-	/* alignment requirement for next block */
 	BUILD_BUG_ON(sizeof(struct alx_rrd) % 8);
 
-	alx->rxq.rfd =
-		(void *)((u8 *)alx->descmem.virt +
-			 sizeof(struct alx_txd) * alx->tx_ringsz +
-			 sizeof(struct alx_rrd) * alx->rx_ringsz);
-	alx->rxq.rfd_dma = alx->descmem.dma +
-			   sizeof(struct alx_txd) * alx->tx_ringsz +
-			   sizeof(struct alx_rrd) * alx->rx_ringsz;
-
-	return 0;
-out_free:
-	kfree(alx->txq.bufs);
-	kfree(alx->rxq.bufs);
-	return -ENOMEM;
-}
-
-static int alx_alloc_rings(struct alx_priv *alx)
-{
-	int err;
+	offset = alx_alloc_tx_ring(alx, &alx->txq, offset);
+	if (offset < 0) {
+		netdev_err(alx->dev, "Allocation of tx buffer failed!\n");
+		goto out_free;
+	}
 
-	err = alx_alloc_descriptors(alx);
-	if (err)
-		return err;
+	offset = alx_alloc_rx_ring(alx, &alx->rxq, offset);
+	if (offset < 0) {
+		netdev_err(alx->dev, "Allocation of rx buffer failed!\n");
+		goto out_free;
+	}
 
 	alx->int_mask &= ~ALX_ISR_ALL_QUEUES;
 	alx->int_mask |= ALX_ISR_TX_Q0 | ALX_ISR_RX_Q0;
@@ -647,7 +647,16 @@ static int alx_alloc_rings(struct alx_priv *alx)
 	netif_napi_add(alx->dev, &alx->napi, alx_poll, 64);
 
 	alx_reinit_rings(alx);
+
 	return 0;
+out_free:
+	kfree(alx->txq.bufs);
+	kfree(alx->rxq.bufs);
+	dma_free_coherent(&alx->hw.pdev->dev,
+			  alx->descmem.size,
+			  alx->descmem.virt,
+			  alx->descmem.dma);
+	return -ENOMEM;
 }
 
 static void alx_free_rings(struct alx_priv *alx)