KS8851: Correct RX packet allocation

Use netdev_alloc_skb_ip_align() helper and do correct allocation

Tested-by: Abraham Arce <[e-mail]>
Signed-off-by: Abraham Arce <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ks8851.c

···
 		ks8851_wrreg16(ks, KS_RXQCR,
 			       ks->rc_rxqcr | RXQCR_SDA | RXQCR_ADRFE);
 
-		if (rxlen > 0) {
-			skb = netdev_alloc_skb(ks->netdev, rxlen + 2 + 8);
-			if (!skb) {
-				/* todo - dump frame and move on */
+		if (rxlen > 4) {
+			unsigned int rxalign;
+
+			rxlen -= 4;
+			rxalign = ALIGN(rxlen, 4);
+			skb = netdev_alloc_skb_ip_align(ks->netdev, rxalign);
+			if (skb) {
+
+				/* 4 bytes of status header + 4 bytes of
+				 * garbage: we put them before ethernet
+				 * header, so that they are copied,
+				 * but ignored.
+				 */
+
+				rxpkt = skb_put(skb, rxlen) - 8;
+
+				ks8851_rdfifo(ks, rxpkt, rxalign + 8);
+
+				if (netif_msg_pktdata(ks))
+					ks8851_dbg_dumpkkt(ks, rxpkt);
+
+				skb->protocol = eth_type_trans(skb, ks->netdev);
+				netif_rx(skb);
+
+				ks->netdev->stats.rx_packets++;
+				ks->netdev->stats.rx_bytes += rxlen;
 			}
-
-			/* two bytes to ensure ip is aligned, and four bytes
-			 * for the status header and 4 bytes of garbage */
-			skb_reserve(skb, 2 + 4 + 4);
-
-			rxpkt = skb_put(skb, rxlen - 4) - 8;
-
-			/* align the packet length to 4 bytes, and add 4 bytes
-			 * as we're getting the rx status header as well */
-			ks8851_rdfifo(ks, rxpkt, ALIGN(rxlen, 4) + 8);
-
-			if (netif_msg_pktdata(ks))
-				ks8851_dbg_dumpkkt(ks, rxpkt);
-
-			skb->protocol = eth_type_trans(skb, ks->netdev);
-			netif_rx(skb);
-
-			ks->netdev->stats.rx_packets++;
-			ks->netdev->stats.rx_bytes += rxlen - 4;
 		}
 
 		ks8851_wrreg16(ks, KS_RXQCR, ks->rc_rxqcr);