From b853f31940c84cce6a3f5cb4f529b029906ee69c Mon Sep 17 00:00:00 2001
From: Jonas Jensen <jonas.jensen@gmail.com>
Date: Mon, 25 Aug 2014 16:22:11 +0200
Subject: net: moxa: clear DESC1 on ndo_start_xmit()

TX buffer length is not cleared on ndo_start_xmit().
Failing to do so can bug/hang the controller and
cause TX interrupts to stop altogether.

Remove the readl() and compute a new value for DESC1.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69031

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/moxa/moxart_ether.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

(limited to 'drivers/net/ethernet/moxa/moxart_ether.c')

diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index 5020fd47825..eed70d9f0d9 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -346,10 +346,9 @@ static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 		len = ETH_ZLEN;
 	}
 
-	txdes1 = readl(desc + TX_REG_OFFSET_DESC1);
-	txdes1 |= TX_DESC1_LTS | TX_DESC1_FTS;
-	txdes1 &= ~(TX_DESC1_FIFO_COMPLETE | TX_DESC1_INTR_COMPLETE);
-	txdes1 |= (len & TX_DESC1_BUF_SIZE_MASK);
+	txdes1 = TX_DESC1_LTS | TX_DESC1_FTS | (len & TX_DESC1_BUF_SIZE_MASK);
+	if (tx_head == TX_DESC_NUM_MASK)
+		txdes1 |= TX_DESC1_END;
 	writel(txdes1, desc + TX_REG_OFFSET_DESC1);
 	writel(TX_DESC0_DMA_OWN, desc + TX_REG_OFFSET_DESC0);
 
-- 
cgit v1.2.3-70-g09d2


From 9fe1b3bc8d9182e950a744e4a47187420efa67f3 Mon Sep 17 00:00:00 2001
From: Jonas Jensen <jonas.jensen@gmail.com>
Date: Mon, 25 Aug 2014 16:22:22 +0200
Subject: net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() /
 memcpy()

build_skb() is used to make skbs out of existing RX ring memory
which is bad because the RX ring is allocated only once, on probe.
Memory corruption occur because said memory is reclaimed, i.e.
__kfree_skb() (and eventually put_page()).

Replace build_skb() with netdev_alloc_skb_ip_align() and use memcpy().

Remove SKB_DATA_ALIGN() from RX buffer size while we're at it.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69041

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/moxa/moxart_ether.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

(limited to 'drivers/net/ethernet/moxa/moxart_ether.c')

diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index eed70d9f0d9..d66058d5c42 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -226,13 +226,15 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget)
 		if (len > RX_BUF_SIZE)
 			len = RX_BUF_SIZE;
 
-		skb = build_skb(priv->rx_buf[rx_head], priv->rx_buf_size);
+		skb = netdev_alloc_skb_ip_align(ndev, len);
+
 		if (unlikely(!skb)) {
-			net_dbg_ratelimited("build_skb failed\n");
+			net_dbg_ratelimited("netdev_alloc_skb_ip_align failed\n");
 			priv->stats.rx_dropped++;
 			priv->stats.rx_errors++;
 		}
 
+		memcpy(skb->data, priv->rx_buf[rx_head], len);
 		skb_put(skb, len);
 		skb->protocol = eth_type_trans(skb, ndev);
 		napi_gro_receive(&priv->napi, skb);
@@ -464,8 +466,7 @@ static int moxart_mac_probe(struct platform_device *pdev)
 	spin_lock_init(&priv->txlock);
 
 	priv->tx_buf_size = TX_BUF_SIZE;
-	priv->rx_buf_size = RX_BUF_SIZE +
-			    SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	priv->rx_buf_size = RX_BUF_SIZE;
 
 	priv->tx_desc_base = dma_alloc_coherent(NULL, TX_REG_DESC_SIZE *
 						TX_DESC_NUM, &priv->tx_base,
-- 
cgit v1.2.3-70-g09d2


From 777fbc31447f111a1492c90fae2bc616f836d407 Mon Sep 17 00:00:00 2001
From: Jonas Jensen <jonas.jensen@gmail.com>
Date: Mon, 25 Aug 2014 16:22:32 +0200
Subject: net: moxa: synchronize DMA memory

DMA memory should be synchronized before data is passed
to/from controller.

Add dma_sync_single_for_cpu(.., DMA_FROM_DEVICE) to RX path
and dma_sync_single_for_device(.., DMA_TO_DEVICE) to TX path.

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/moxa/moxart_ether.c | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'drivers/net/ethernet/moxa/moxart_ether.c')

diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index d66058d5c42..983d0194979 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -226,6 +226,9 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget)
 		if (len > RX_BUF_SIZE)
 			len = RX_BUF_SIZE;
 
+		dma_sync_single_for_cpu(&ndev->dev,
+					priv->rx_mapping[rx_head],
+					priv->rx_buf_size, DMA_FROM_DEVICE);
 		skb = netdev_alloc_skb_ip_align(ndev, len);
 
 		if (unlikely(!skb)) {
@@ -348,6 +351,9 @@ static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 		len = ETH_ZLEN;
 	}
 
+	dma_sync_single_for_device(&ndev->dev, priv->tx_mapping[tx_head],
+				   priv->tx_buf_size, DMA_TO_DEVICE);
+
 	txdes1 = TX_DESC1_LTS | TX_DESC1_FTS | (len & TX_DESC1_BUF_SIZE_MASK);
 	if (tx_head == TX_DESC_NUM_MASK)
 		txdes1 |= TX_DESC1_END;
-- 
cgit v1.2.3-70-g09d2


From 2b7890e757bc42f963c835521c2657bd16d7b7d6 Mon Sep 17 00:00:00 2001
From: Jonas Jensen <jonas.jensen@gmail.com>
Date: Mon, 25 Aug 2014 16:22:40 +0200
Subject: net: moxa: continue loop on skb allocation failure

If netdev_alloc_skb_ip_align() fails, subsequent code will
try to dereference an invalid pointer.

Continue to next descriptor on error.

While we're at it,

1. eliminate the chance of an endless loop, replace the main
   loop with while(rx < budget)

2. use napi_complete() and remove the explicit napi_gro_flush()

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/moxa/moxart_ether.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

(limited to 'drivers/net/ethernet/moxa/moxart_ether.c')

diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index 983d0194979..2f12c88c66a 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -206,7 +206,7 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget)
 	int rx_head = priv->rx_head;
 	int rx = 0;
 
-	while (1) {
+	while (rx < budget) {
 		desc = priv->rx_desc_base + (RX_REG_DESC_SIZE * rx_head);
 		desc0 = readl(desc + RX_REG_OFFSET_DESC0);
 
@@ -218,7 +218,7 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget)
 			net_dbg_ratelimited("packet error\n");
 			priv->stats.rx_dropped++;
 			priv->stats.rx_errors++;
-			continue;
+			goto rx_next;
 		}
 
 		len = desc0 & RX_DESC0_FRAME_LEN_MASK;
@@ -235,6 +235,7 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget)
 			net_dbg_ratelimited("netdev_alloc_skb_ip_align failed\n");
 			priv->stats.rx_dropped++;
 			priv->stats.rx_errors++;
+			goto rx_next;
 		}
 
 		memcpy(skb->data, priv->rx_buf[rx_head], len);
@@ -249,18 +250,15 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget)
 		if (desc0 & RX_DESC0_MULTICAST)
 			priv->stats.multicast++;
 
+rx_next:
 		writel(RX_DESC0_DMA_OWN, desc + RX_REG_OFFSET_DESC0);
 
 		rx_head = RX_NEXT(rx_head);
 		priv->rx_head = rx_head;
-
-		if (rx >= budget)
-			break;
 	}
 
 	if (rx < budget) {
-		napi_gro_flush(napi, false);
-		__napi_complete(napi);
+		napi_complete(napi);
 	}
 
 	priv->reg_imr |= RPKT_FINISH_M;
-- 
cgit v1.2.3-70-g09d2