r8169: remove unneeded dirty_rx index

After commit 6f0333b ("r8169: use 50% less ram for RX ring") the rx
ring buffers are always copied making dirty_rx useless.

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Acked-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -83,7 +83,7 @@ static const int multicast_filter_limit = 32;
 #define R8169_REGS_SIZE		256
 #define R8169_NAPI_WEIGHT	64
 #define NUM_TX_DESC	64	/* Number of Tx descriptor registers */
-#define NUM_RX_DESC	256	/* Number of Rx descriptor registers */
+#define NUM_RX_DESC	256U	/* Number of Rx descriptor registers */
 #define R8169_TX_RING_BYTES	(NUM_TX_DESC * sizeof(struct TxDesc))
 #define R8169_RX_RING_BYTES	(NUM_RX_DESC * sizeof(struct RxDesc))
 
@@ -727,7 +727,6 @@ struct rtl8169_private {
 	u16 mac_version;
 	u32 cur_rx; /* Index into the Rx descriptor buffer of next Rx pkt. */
 	u32 cur_tx; /* Index into the Tx descriptor buffer of next Rx pkt. */
-	u32 dirty_rx;
 	u32 dirty_tx;
 	struct rtl8169_stats rx_stats;
 	struct rtl8169_stats tx_stats;
@@ -4177,7 +4176,7 @@ static void rtl_init_rxcfg(struct rtl8169_private *tp)
 
 static void rtl8169_init_ring_indexes(struct rtl8169_private *tp)
 {
-	tp->dirty_tx = tp->dirty_rx = tp->cur_tx = tp->cur_rx = 0;
+	tp->dirty_tx = tp->cur_tx = tp->cur_rx = 0;
 }
 
 static void rtl_hw_jumbo_enable(struct rtl8169_private *tp)
@@ -5920,7 +5919,7 @@ static void rtl8169_pcierr_interrupt(struct net_device *dev)
 		PCI_STATUS_REC_TARGET_ABORT | PCI_STATUS_SIG_TARGET_ABORT));
 
 	/* The infamous DAC f*ckup only happens at boot time */
-	if ((tp->cp_cmd & PCIDAC) && !tp->dirty_rx && !tp->cur_rx) {
+	if ((tp->cp_cmd & PCIDAC) && !tp->cur_rx) {
 		void __iomem *ioaddr = tp->mmio_addr;
 
 		netif_info(tp, intr, dev, "disabling PCI DAC\n");
@@ -6035,10 +6034,8 @@ static int rtl_rx(struct net_device *dev, struct rtl8169_private *tp, u32 budget
 	unsigned int count;
 
 	cur_rx = tp->cur_rx;
-	rx_left = NUM_RX_DESC + tp->dirty_rx - cur_rx;
-	rx_left = min(rx_left, budget);
 
-	for (; rx_left > 0; rx_left--, cur_rx++) {
+	for (rx_left = min(budget, NUM_RX_DESC); rx_left > 0; rx_left--, cur_rx++) {
 		unsigned int entry = cur_rx % NUM_RX_DESC;
 		struct RxDesc *desc = tp->RxDescArray + entry;
 		u32 status;
@@ -6123,8 +6120,6 @@ process_pkt:
 	count = cur_rx - tp->cur_rx;
 	tp->cur_rx = cur_rx;
 
-	tp->dirty_rx += count;
-
 	return count;
 }