3 files changed, 40 insertions, 25 deletions

diff --git a/drivers/net/ethernet/micrel/ks8851.h b/drivers/net/ethernet/micrel/ks8851.h
index fecd43754cea..e5ec0a363aff 100644
--- a/drivers/net/ethernet/micrel/ks8851.h
+++ b/drivers/net/ethernet/micrel/ks8851.h
@@ -350,6 +350,8 @@ union ks8851_tx_hdr {
  * @rxd: Space for receiving SPI data, in DMA-able space.
  * @txd: Space for transmitting SPI data, in DMA-able space.
  * @msg_enable: The message flags controlling driver output (see ethtool).
+ * @tx_space: Free space in the hardware TX buffer (cached copy of KS_TXMIR).
+ * @queued_len: Space required in hardware TX buffer for queued packets in txq.
  * @fid: Incrementing frame id tag.
  * @rc_ier: Cached copy of KS_IER.
  * @rc_ccr: Cached copy of KS_CCR.
@@ -399,6 +401,7 @@ struct ks8851_net {
 	struct work_struct	rxctrl_work;
 
 	struct sk_buff_head	txq;
+	unsigned int		queued_len;
 
 	struct eeprom_93cx6	eeprom;
 	struct regulator	*vdd_reg;
diff --git a/drivers/net/ethernet/micrel/ks8851_common.c b/drivers/net/ethernet/micrel/ks8851_common.c
index cfbc900d4aeb..0bf13b38b8f5 100644
--- a/drivers/net/ethernet/micrel/ks8851_common.c
+++ b/drivers/net/ethernet/micrel/ks8851_common.c
@@ -362,16 +362,18 @@ static irqreturn_t ks8851_irq(int irq, void *_ks)
 		handled |= IRQ_RXPSI;
 
 	if (status & IRQ_TXI) {
-		handled |= IRQ_TXI;
+		unsigned short tx_space = ks8851_rdreg16(ks, KS_TXMIR);
 
-		/* no lock here, tx queue should have been stopped */
+		netif_dbg(ks, intr, ks->netdev,
+			  "%s: txspace %d\n", __func__, tx_space);
 
-		/* update our idea of how much tx space is available to the
-		 * system */
-		ks->tx_space = ks8851_rdreg16(ks, KS_TXMIR);
+		spin_lock(&ks->statelock);
+		ks->tx_space = tx_space;
+		if (netif_queue_stopped(ks->netdev))
+			netif_wake_queue(ks->netdev);
+		spin_unlock(&ks->statelock);
 
-		netif_dbg(ks, intr, ks->netdev,
-			  "%s: txspace %d\n", __func__, ks->tx_space);
+		handled |= IRQ_TXI;
 	}
 
 	if (status & IRQ_RXI)
@@ -414,9 +416,6 @@ static irqreturn_t ks8851_irq(int irq, void *_ks)
 	if (status & IRQ_LCI)
 		mii_check_link(&ks->mii);
 
-	if (status & IRQ_TXI)
-		netif_wake_queue(ks->netdev);
-
 	return IRQ_HANDLED;
 }
 
@@ -500,6 +499,7 @@ static int ks8851_net_open(struct net_device *dev)
 	ks8851_wrreg16(ks, KS_ISR, ks->rc_ier);
 	ks8851_wrreg16(ks, KS_IER, ks->rc_ier);
 
+	ks->queued_len = 0;
 	netif_start_queue(ks->netdev);
 
 	netif_dbg(ks, ifup, ks->netdev, "network device up\n");
diff --git a/drivers/net/ethernet/micrel/ks8851_spi.c b/drivers/net/ethernet/micrel/ks8851_spi.c
index 70bc7253454f..88e26c120b48 100644
--- a/drivers/net/ethernet/micrel/ks8851_spi.c
+++ b/drivers/net/ethernet/micrel/ks8851_spi.c
@@ -287,6 +287,18 @@ static void ks8851_wrfifo_spi(struct ks8851_net *ks, struct sk_buff *txp,
 }
 
 /**
+ * calc_txlen - calculate size of message to send packet
+ * @len: Length of data
+ *
+ * Returns the size of the TXFIFO message needed to send
+ * this packet.
+ */
+static unsigned int calc_txlen(unsigned int len)
+{
+	return ALIGN(len + 4, 4);
+}
+
+/**
  * ks8851_rx_skb_spi - receive skbuff
  * @ks: The device state
  * @skb: The skbuff
@@ -305,7 +317,9 @@ static void ks8851_rx_skb_spi(struct ks8851_net *ks, struct sk_buff *skb)
  */
 static void ks8851_tx_work(struct work_struct *work)
 {
+	unsigned int dequeued_len = 0;
 	struct ks8851_net_spi *kss;
+	unsigned short tx_space;
 	struct ks8851_net *ks;
 	unsigned long flags;
 	struct sk_buff *txb;
@@ -322,6 +336,8 @@ static void ks8851_tx_work(struct work_struct *work)
 		last = skb_queue_empty(&ks->txq);
 
 		if (txb) {
+			dequeued_len += calc_txlen(txb->len);
+
 			ks8851_wrreg16_spi(ks, KS_RXQCR,
 					   ks->rc_rxqcr | RXQCR_SDA);
 			ks8851_wrfifo_spi(ks, txb, last);
@@ -332,6 +348,13 @@ static void ks8851_tx_work(struct work_struct *work)
 		}
 	}
 
+	tx_space = ks8851_rdreg16_spi(ks, KS_TXMIR);
+
+	spin_lock(&ks->statelock);
+	ks->queued_len -= dequeued_len;
+	ks->tx_space = tx_space;
+	spin_unlock(&ks->statelock);
+
 	ks8851_unlock_spi(ks, &flags);
 }
 
@@ -347,18 +370,6 @@ static void ks8851_flush_tx_work_spi(struct ks8851_net *ks)
 }
 
 /**
- * calc_txlen - calculate size of message to send packet
- * @len: Length of data
- *
- * Returns the size of the TXFIFO message needed to send
- * this packet.
- */
-static unsigned int calc_txlen(unsigned int len)
-{
-	return ALIGN(len + 4, 4);
-}
-
-/**
  * ks8851_start_xmit_spi - transmit packet using SPI
  * @skb: The buffer to transmit
  * @dev: The device used to transmit the packet.
@@ -386,16 +397,17 @@ static netdev_tx_t ks8851_start_xmit_spi(struct sk_buff *skb,
 
 	spin_lock(&ks->statelock);
 
-	if (needed > ks->tx_space) {
+	if (ks->queued_len + needed > ks->tx_space) {
 		netif_stop_queue(dev);
 		ret = NETDEV_TX_BUSY;
 	} else {
-		ks->tx_space -= needed;
+		ks->queued_len += needed;
 		skb_queue_tail(&ks->txq, skb);
 	}
 
 	spin_unlock(&ks->statelock);
-	schedule_work(&kss->tx_work);
+	if (ret == NETDEV_TX_OK)
+		schedule_work(&kss->tx_work);
 
 	return ret;
 }