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SubjectRe: [PATCH] wan: dscc4: add checks for dma mapping errors
Alexey Khoroshilov <khoroshilov@ispras.ru> :
> The driver does not check if mapping dma memory succeed.
> The patch adds the checks and failure handling.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>

Please amend your subject line as:

Subject: [PATCH net-next v2 1/1] dscc4: add checks for dma mapping errors.

Rationale: davem is not supposed to guess the branch the patch should be
applied to.

[...]
> diff --git a/drivers/net/wan/dscc4.c b/drivers/net/wan/dscc4.c
> index 799830ffcae2..1a94f0a95b2c 100644
> --- a/drivers/net/wan/dscc4.c
> +++ b/drivers/net/wan/dscc4.c
> @@ -522,19 +522,27 @@ static inline int try_get_rx_skb(struct dscc4_dev_priv *dpriv,
> struct RxFD *rx_fd = dpriv->rx_fd + dirty;
> const int len = RX_MAX(HDLC_MAX_MRU);
> struct sk_buff *skb;
> - int ret = 0;
> + dma_addr_t addr;
>
> skb = dev_alloc_skb(len);
> dpriv->rx_skbuff[dirty] = skb;
> - if (skb) {
> - skb->protocol = hdlc_type_trans(skb, dev);
> - rx_fd->data = cpu_to_le32(pci_map_single(dpriv->pci_priv->pdev,
> - skb->data, len, PCI_DMA_FROMDEVICE));
> - } else {
> - rx_fd->data = 0;
> - ret = -1;
> - }
> - return ret;
> + if (!skb)
> + goto err_out;
> +
> + skb->protocol = hdlc_type_trans(skb, dev);
> + addr = pci_map_single(dpriv->pci_priv->pdev,
> + skb->data, len, PCI_DMA_FROMDEVICE);
> + if (pci_dma_mapping_error(dpriv->pci_priv->pdev, addr))
> + goto err_free_skb;

Nit: please use a local 'struct pci_dev *pdev = dpriv->pci_priv->pdev;'

[...]
> @@ -1147,14 +1155,22 @@ static netdev_tx_t dscc4_start_xmit(struct sk_buff *skb,
> struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
> struct dscc4_pci_priv *ppriv = dpriv->pci_priv;
> struct TxFD *tx_fd;
> + dma_addr_t addr;
> int next;
>
> + addr = pci_map_single(ppriv->pdev, skb->data, skb->len,
> + PCI_DMA_TODEVICE);
> + if (pci_dma_mapping_error(ppriv->pdev, addr)) {
> + dev_kfree_skb_any(skb);
> + dev->stats.tx_errors++;

It should read 'dev->stats.tx_dropped++'.

--
Ueimor

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