forcedeth: remove unnecessary structure member

Since both tx_ring and first_tx are the head of tx ring, it not
necessary to use two structure members to statically indicate
the head of tx ring. So first_tx is removed.

CC: Srinivas Eeda <srinivas.eeda@oracle.com>
CC: Joe Jin <joe.jin@oracle.com>
CC: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/nvidia/forcedeth.c

@@ -822,7 +822,7 @@ struct fe_priv {
 	/*
 	 * tx specific fields.
 	 */
-	union ring_type get_tx, put_tx, first_tx, last_tx;
+	union ring_type get_tx, put_tx, last_tx;
 	struct nv_skb_map *get_tx_ctx, *put_tx_ctx;
 	struct nv_skb_map *first_tx_ctx, *last_tx_ctx;
 	struct nv_skb_map *tx_skb;
@@ -1932,7 +1932,8 @@ static void nv_init_tx(struct net_device *dev)
 	struct fe_priv *np = netdev_priv(dev);
 	int i;
 
-	np->get_tx = np->put_tx = np->first_tx = np->tx_ring;
+	np->get_tx = np->tx_ring;
+	np->put_tx = np->tx_ring;
 
 	if (!nv_optimized(np))
 		np->last_tx.orig = &np->tx_ring.orig[np->tx_ring_size-1];
@@ -2248,7 +2249,7 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		offset += bcnt;
 		size -= bcnt;
 		if (unlikely(put_tx++ == np->last_tx.orig))
-			put_tx = np->first_tx.orig;
+			put_tx = np->tx_ring.orig;
 		if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
 			np->put_tx_ctx = np->first_tx_ctx;
 	} while (size);
@@ -2294,13 +2295,13 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
 			offset += bcnt;
 			frag_size -= bcnt;
 			if (unlikely(put_tx++ == np->last_tx.orig))
-				put_tx = np->first_tx.orig;
+				put_tx = np->tx_ring.orig;
 			if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
 				np->put_tx_ctx = np->first_tx_ctx;
 		} while (frag_size);
 	}
 
-	if (unlikely(put_tx == np->first_tx.orig))
+	if (unlikely(put_tx == np->tx_ring.orig))
 		prev_tx = np->last_tx.orig;
 	else
 		prev_tx = put_tx - 1;
@@ -2406,7 +2407,7 @@ static netdev_tx_t nv_start_xmit_optimized(struct sk_buff *skb,
 		offset += bcnt;
 		size -= bcnt;
 		if (unlikely(put_tx++ == np->last_tx.ex))
-			put_tx = np->first_tx.ex;
+			put_tx = np->tx_ring.ex;
 		if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
 			np->put_tx_ctx = np->first_tx_ctx;
 	} while (size);
@@ -2452,13 +2453,13 @@ static netdev_tx_t nv_start_xmit_optimized(struct sk_buff *skb,
 			offset += bcnt;
 			frag_size -= bcnt;
 			if (unlikely(put_tx++ == np->last_tx.ex))
-				put_tx = np->first_tx.ex;
+				put_tx = np->tx_ring.ex;
 			if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
 				np->put_tx_ctx = np->first_tx_ctx;
 		} while (frag_size);
 	}
 
-	if (unlikely(put_tx == np->first_tx.ex))
+	if (unlikely(put_tx == np->tx_ring.ex))
 		prev_tx = np->last_tx.ex;
 	else
 		prev_tx = put_tx - 1;
@@ -2597,7 +2598,7 @@ static int nv_tx_done(struct net_device *dev, int limit)
 			}
 		}
 		if (unlikely(np->get_tx.orig++ == np->last_tx.orig))
-			np->get_tx.orig = np->first_tx.orig;
+			np->get_tx.orig = np->tx_ring.orig;
 		if (unlikely(np->get_tx_ctx++ == np->last_tx_ctx))
 			np->get_tx_ctx = np->first_tx_ctx;
 	}
@@ -2651,7 +2652,7 @@ static int nv_tx_done_optimized(struct net_device *dev, int limit)
 		}
 
 		if (unlikely(np->get_tx.ex++ == np->last_tx.ex))
-			np->get_tx.ex = np->first_tx.ex;
+			np->get_tx.ex = np->tx_ring.ex;
 		if (unlikely(np->get_tx_ctx++ == np->last_tx_ctx))
 			np->get_tx_ctx = np->first_tx_ctx;
 	}