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SubjectRe: [PATCH v2 1/2] net: macb: Check DMA mappings for error
Hi Ben,

On Thu, 2014-02-27 at 11:57PM +0000, Ben Hutchings wrote:
> On Thu, 2014-02-27 at 13:58 -0800, Soren Brinkmann wrote:
> [...]
> > diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> > index 3190d38e16fb..a9c2ccfc1740 100644
> > --- a/drivers/net/ethernet/cadence/macb.c
> > +++ b/drivers/net/ethernet/cadence/macb.c
> > @@ -632,11 +632,16 @@ static void gem_rx_refill(struct macb *bp)
> > "Unable to allocate sk_buff\n");
> > break;
> > }
> > - bp->rx_skbuff[entry] = skb;
> >
> > /* now fill corresponding descriptor entry */
> > paddr = dma_map_single(&bp->pdev->dev, skb->data,
> > bp->rx_buffer_size, DMA_FROM_DEVICE);
> > + if (dma_mapping_error(&bp->pdev->dev, paddr)) {
> > + dev_kfree_skb(skb);
> > + break;
> > + }
> > +
> > + bp->rx_skbuff[entry] = skb;
> >
> > if (entry == RX_RING_SIZE - 1)
> > paddr |= MACB_BIT(RX_WRAP);
> > @@ -1040,6 +1045,10 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
>
> A bit more context:
>
> entry = macb_tx_ring_wrap(bp->tx_head);
> bp->tx_head++;
>
> > netdev_vdbg(bp->dev, "Allocated ring entry %u\n", entry);
> > mapping = dma_map_single(&bp->pdev->dev, skb->data,
> > len, DMA_TO_DEVICE);
> > + if (dma_mapping_error(&bp->pdev->dev, mapping)) {
> > + kfree_skb(skb);
> > + goto unlock;
> > + }
>
> You need to move the bp->tx_head increment below this error check.
> Sorry I didn't spot this the first time.

No problem. I'll wait till next week with a re-spin, in case somebody
else has comments.

Sören


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