Linux-libre 4.3.2-gnu

1 files changed, 34 insertions, 19 deletions

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index de63266de..dd4ca39d5 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -364,7 +364,7 @@ fec_enet_clear_csum(struct sk_buff *skb, struct net_device *ndev)
 	return 0;
 }
 
-static int
+static struct bufdesc *
 fec_enet_txq_submit_frag_skb(struct fec_enet_priv_tx_q *txq,
 			     struct sk_buff *skb,
 			     struct net_device *ndev)
@@ -439,10 +439,7 @@ fec_enet_txq_submit_frag_skb(struct fec_enet_priv_tx_q *txq,
 		bdp->cbd_sc = status;
 	}
 
-	txq->cur_tx = bdp;
-
-	return 0;
-
+	return bdp;
 dma_mapping_error:
 	bdp = txq->cur_tx;
 	for (i = 0; i < frag; i++) {
@@ -450,7 +447,7 @@ dma_mapping_error:
 		dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
 				bdp->cbd_datlen, DMA_TO_DEVICE);
 	}
-	return NETDEV_TX_OK;
+	return ERR_PTR(-ENOMEM);
 }
 
 static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq,
@@ -467,7 +464,6 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq,
 	unsigned int estatus = 0;
 	unsigned int index;
 	int entries_free;
-	int ret;
 
 	entries_free = fec_enet_get_free_txdesc_num(fep, txq);
 	if (entries_free < MAX_SKB_FRAGS + 1) {
@@ -485,6 +481,7 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq,
 
 	/* Fill in a Tx ring entry */
 	bdp = txq->cur_tx;
+	last_bdp = bdp;
 	status = bdp->cbd_sc;
 	status &= ~BD_ENET_TX_STATS;
 
@@ -513,9 +510,9 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq,
 	}
 
 	if (nr_frags) {
-		ret = fec_enet_txq_submit_frag_skb(txq, skb, ndev);
-		if (ret)
-			return ret;
+		last_bdp = fec_enet_txq_submit_frag_skb(txq, skb, ndev);
+		if (IS_ERR(last_bdp))
+			return NETDEV_TX_OK;
 	} else {
 		status |= (BD_ENET_TX_INTR | BD_ENET_TX_LAST);
 		if (fep->bufdesc_ex) {
@@ -544,7 +541,6 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq,
 		ebdp->cbd_esc = estatus;
 	}
 
-	last_bdp = txq->cur_tx;
 	index = fec_enet_get_bd_index(txq->tx_bd_base, last_bdp, fep);
 	/* Save skb pointer */
 	txq->tx_skbuff[index] = skb;
@@ -563,6 +559,10 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq,
 
 	skb_tx_timestamp(skb);
 
+	/* Make sure the update to bdp and tx_skbuff are performed before
+	 * cur_tx.
+	 */
+	wmb();
 	txq->cur_tx = bdp;
 
 	/* Trigger transmission start */
@@ -1218,10 +1218,11 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id)
 	/* get next bdp of dirty_tx */
 	bdp = fec_enet_get_nextdesc(bdp, fep, queue_id);
 
-	while (((status = bdp->cbd_sc) & BD_ENET_TX_READY) == 0) {
-
-		/* current queue is empty */
-		if (bdp == txq->cur_tx)
+	while (bdp != READ_ONCE(txq->cur_tx)) {
+		/* Order the load of cur_tx and cbd_sc */
+		rmb();
+		status = READ_ONCE(bdp->cbd_sc);
+		if (status & BD_ENET_TX_READY)
 			break;
 
 		index = fec_enet_get_bd_index(txq->tx_bd_base, bdp, fep);
@@ -1275,6 +1276,10 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id)
 		/* Free the sk buffer associated with this last transmit */
 		dev_kfree_skb_any(skb);
 
+		/* Make sure the update to bdp and tx_skbuff are performed
+		 * before dirty_tx
+		 */
+		wmb();
 		txq->dirty_tx = bdp;
 
 		/* Update pointer to next buffer descriptor to be transmitted */
@@ -1775,7 +1780,7 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 	int ret = 0;
 
 	ret = pm_runtime_get_sync(dev);
-	if (IS_ERR_VALUE(ret))
+	if (ret < 0)
 		return ret;
 
 	fep->mii_timeout = 0;
@@ -1811,11 +1816,13 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 	struct fec_enet_private *fep = bus->priv;
 	struct device *dev = &fep->pdev->dev;
 	unsigned long time_left;
-	int ret = 0;
+	int ret;
 
 	ret = pm_runtime_get_sync(dev);
-	if (IS_ERR_VALUE(ret))
+	if (ret < 0)
 		return ret;
+	else
+		ret = 0;
 
 	fep->mii_timeout = 0;
 	reinit_completion(&fep->mdio_done);
@@ -2866,7 +2873,7 @@ fec_enet_open(struct net_device *ndev)
 	int ret;
 
 	ret = pm_runtime_get_sync(&fep->pdev->dev);
-	if (IS_ERR_VALUE(ret))
+	if (ret < 0)
 		return ret;
 
 	pinctrl_pm_select_default_state(&fep->pdev->dev);
@@ -3024,6 +3031,14 @@ fec_set_mac_address(struct net_device *ndev, void *p)
 		memcpy(ndev->dev_addr, addr->sa_data, ndev->addr_len);
 	}
 
+	/* Add netif status check here to avoid system hang in below case:
+	 * ifconfig ethx down; ifconfig ethx hw ether xx:xx:xx:xx:xx:xx;
+	 * After ethx down, fec all clocks are gated off and then register
+	 * access causes system hang.
+	 */
+	if (!netif_running(ndev))
+		return 0;
+
 	writel(ndev->dev_addr[3] | (ndev->dev_addr[2] << 8) |
 		(ndev->dev_addr[1] << 16) | (ndev->dev_addr[0] << 24),
 		fep->hwp + FEC_ADDR_LOW);