Re: [PATCH 3/4] Add error check for pci_map_single return value in rtl8180 TX path

[Larry Finger <Larry.Finger@lwfinger.net>]

On 02/05/2014 03:38 PM, andrea merello wrote:
> From: "andrea.merello" <andrea.merello@gmail.com>
>
> Orignal code will not detect a DMA mapping failure, causing the HW
> to attempt a DMA from an invalid address.
>
> This patch add the error check and eventually simply drops the TX
> packet if we can't map it for DMA.
>
> Signed-off-by: andrea.merello <andrea.merello@gmail.com>
> Signed-off-by: andrea merello <andrea.merello@gmail.com>

This code is standard for recovery from an error in pci_map_single().

Acked-by: Larry Finger <Larry.Finger@lwfinger.net>

Larry

> ---
>   drivers/net/wireless/rtl818x/rtl8180/dev.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/wireless/rtl818x/rtl8180/dev.c b/drivers/net/wireless/rtl818x/rtl8180/dev.c
> index 1c6ac25..9645ed2 100644
> --- a/drivers/net/wireless/rtl818x/rtl8180/dev.c
> +++ b/drivers/net/wireless/rtl818x/rtl8180/dev.c
> @@ -276,6 +276,13 @@ static void rtl8180_tx(struct ieee80211_hw *dev,
>   	mapping = pci_map_single(priv->pdev, skb->data,
>   				 skb->len, PCI_DMA_TODEVICE);
>
> +	if (pci_dma_mapping_error(priv->pdev, mapping)) {
> +		kfree_skb(skb);
> +		dev_err(&priv->pdev->dev, "TX DMA mapping error\n");
> +		return;
> +
> +	}
> +
>   	tx_flags = RTL818X_TX_DESC_FLAG_OWN | RTL818X_TX_DESC_FLAG_FS |
>   		   RTL818X_TX_DESC_FLAG_LS |
>   		   (ieee80211_get_tx_rate(dev, info)->hw_value << 24) |
>