Re: [net PATCH] atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring

Luis Henriques
2013-07-26T16:56:16Z

Neil Horman <nhorman@tuxdriver.com> writes:

> atl1c uses netdev_alloc_skb to refill its rx dma ring, but that call makes no
> guarantees about the suitability of the memory for use in DMA. As a result
> we've gotten reports of atl1c drivers occasionally hanging and needing to be
> reset:
> https://bugzilla.kernel.org/show_bug.cgi?id=54021
>
> Fix this by modifying the call to use the internal version __netdev_alloc_skb,
> where you can set the gfp_mask explicitly to include GFP_DMA.
>
> Tested by two reporters in the above bug, who have the hardware to validate it.
> Both report immediate cessation of the problem with this patch
>
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> CC: Jay Cliburn <jcliburn@gmail.com>
> CC: "David S. Miller" <davem@davemloft.net>
> CC: stable@vger.kernel.org
> Tested-by: Luis Henrix <luis.henrix@gmail.com>

Thanks Neil!

Would it be possible for you to update my name and email? (I've just
updated my bz account to remove my gmail account address -- I thought
I had done this ages ago.)

Tested-by: Luis Henriques <luis.henriques@canonical.com>

Cheers,
--
Luis

> Tested-by: Vincent Alquier <vincent.alquier@gmail.com> ---
> drivers/net/ethernet/atheros/atl1c/atl1c_main.c | 2 +- 1 file
> changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> index 786a874..d5e38d1 100644
> --- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> +++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> @@ -1660,7 +1660,7 @@ static int atl1c_alloc_rx_buffer(struct atl1c_adapter *adapter)
> while (next_info->flags & ATL1C_BUFFER_FREE) {
> rfd_desc = ATL1C_RFD_DESC(rfd_ring, rfd_next_to_use);
>
> - skb = netdev_alloc_skb(adapter->netdev, adapter->rx_buffer_len);
> + skb = __netdev_alloc_skb(adapter->netdev, adapter->rx_buffer_len, GFP_ATOMIC|GFP_DMA);
> if (unlikely(!skb)) {
> if (netif_msg_rx_err(adapter))
> dev_warn(&pdev->dev, "alloc rx buffer failed\n");