[ 25/25] 8139cp: Add dma_mapping_error checking

Greg Kroah-Hartman
2013-08-09T01:50:21Z

From: Neil Horman <nhorman@tuxdriver.com>

[ Upstream commit cf3c4c03060b688cbc389ebc5065ebcce5653e96 ]

Self explanitory dma_mapping_error addition to the 8139 driver, based on this:
https://bugzilla.redhat.com/show_bug.cgi?id=947250

It showed several backtraces arising for dma_map_* usage without checking the
return code on the mapping. Add the check and abort the rx/tx operation if its
failed. Untested as I have no hardware and the reporter has wandered off, but
seems pretty straightforward.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/realtek/8139cp.c | 48 +++++++++++++++++++++++++++++++---
1 file changed, 45 insertions(+), 3 deletions(-)

--- a/drivers/net/ethernet/realtek/8139cp.c
+++ b/drivers/net/ethernet/realtek/8139cp.c
@@ -478,7 +478,7 @@ rx_status_loop:

while (1) {
u32 status, len;
- dma_addr_t mapping;
+ dma_addr_t mapping, new_mapping;
struct sk_buff *skb, *new_skb;
struct cp_desc *desc;
const unsigned buflen = cp->rx_buf_sz;
@@ -520,6 +520,13 @@ rx_status_loop:
goto rx_next;
}

+ new_mapping = dma_map_single(&cp->pdev->dev, new_skb->data, buflen,
+ PCI_DMA_FROMDEVICE);
+ if (dma_mapping_error(&cp->pdev->dev, new_mapping)) {
+ dev->stats.rx_dropped++;
+ goto rx_next;
+ }
+
dma_unmap_single(&cp->pdev->dev, mapping,
buflen, PCI_DMA_FROMDEVICE);

@@ -531,12 +538,11 @@ rx_status_loop:

skb_put(skb, len);

- mapping = dma_map_single(&cp->pdev->dev, new_skb->data, buflen,
- PCI_DMA_FROMDEVICE);
cp->rx_skb[rx_tail] = new_skb;

cp_rx_skb(cp, skb, desc);
rx++;
+ mapping = new_mapping;

rx_next:
cp->rx_ring[rx_tail].opts2 = 0;
@@ -704,6 +710,22 @@ static inline u32 cp_tx_vlan_tag(struct
TxVlanTag | swab16(vlan_tx_tag_get(skb)) : 0x00;
}

+static void unwind_tx_frag_mapping(struct cp_private *cp, struct sk_buff *skb,
+ int first, int entry_last)
+{
+ int frag, index;
+ struct cp_desc *txd;
+ skb_frag_t *this_frag;
+ for (frag = 0; frag+first < entry_last; frag++) {
+ index = first+frag;
+ cp->tx_skb[index] = NULL;
+ txd = &cp->tx_ring[index];
+ this_frag = &skb_shinfo(skb)->frags[frag];
+ dma_unmap_single(&cp->pdev->dev, le64_to_cpu(txd->addr),
+ skb_frag_size(this_frag), PCI_DMA_TODEVICE);
+ }
+}
+
static netdev_tx_t cp_start_xmit (struct sk_buff *skb,
struct net_device *dev)
{
@@ -737,6 +759,9 @@ static netdev_tx_t cp_start_xmit (struct

len = skb->len;
mapping = dma_map_single(&cp->pdev->dev, skb->data, len, PCI_DMA_TODEVICE);
+ if (dma_mapping_error(&cp->pdev->dev, mapping))
+ goto out_dma_error;
+
txd->opts2 = opts2;
txd->addr = cpu_to_le64(mapping);
wmb();
@@ -774,6 +799,9 @@ static netdev_tx_t cp_start_xmit (struct
first_len = skb_headlen(skb);
first_mapping = dma_map_single(&cp->pdev->dev, skb->data,
first_len, PCI_DMA_TODEVICE);
+ if (dma_mapping_error(&cp->pdev->dev, first_mapping))
+ goto out_dma_error;
+
cp->tx_skb[entry] = skb;
entry = NEXT_TX(entry);

@@ -787,6 +815,11 @@ static netdev_tx_t cp_start_xmit (struct
mapping = dma_map_single(&cp->pdev->dev,
skb_frag_address(this_frag),
len, PCI_DMA_TODEVICE);
+ if (dma_mapping_error(&cp->pdev->dev, mapping)) {
+ unwind_tx_frag_mapping(cp, skb, first_entry, entry);
+ goto out_dma_error;
+ }
+
eor = (entry == (CP_TX_RING_SIZE - 1)) ? RingEnd : 0;

ctrl = eor | len | DescOwn;
@@ -845,11 +878,16 @@ static netdev_tx_t cp_start_xmit (struct
if (TX_BUFFS_AVAIL(cp) <= (MAX_SKB_FRAGS + 1))
netif_stop_queue(dev);

+out_unlock:
spin_unlock_irqrestore(&cp->lock, intr_flags);

cpw8(TxPoll, NormalTxPoll);

return NETDEV_TX_OK;
+out_dma_error:
+ kfree_skb(skb);
+ cp->dev->stats.tx_dropped++;
+ goto out_unlock;
}

/* Set or clear the multicast filter for this adaptor.
@@ -1020,6 +1058,10 @@ static int cp_refill_rx(struct cp_privat

mapping = dma_map_single(&cp->pdev->dev, skb->data,
cp->rx_buf_sz, PCI_DMA_FROMDEVICE);
+ if (dma_mapping_error(&cp->pdev->dev, mapping)) {
+ kfree_skb(skb);
+ goto err_out;
+ }
cp->rx_skb[i] = skb;

cp->rx_ring[i].opts2 = 0;