Re: [PATCH net] atl1c: Improve driver not to do order 4 GFP_ATOMIC allocation

From: David Miller
Date: Thu Dec 03 2015 - 12:32:57 EST


From: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Date: Thu, 03 Dec 2015 09:17:28 -0800

> On Thu, 2015-12-03 at 16:59 +0100, Pavel Machek wrote:
>> atl1c driver is doing order-4 allocation with GFP_ATOMIC
>> priority. That often breaks networking after resume. Switch to
>> GFP_KERNEL. Still not ideal, but should be significantly better.
>>
>> atl1c_setup_ring_resources() is called from .open() function, and
>> already uses GFP_KERNEL, so this change is safe.
>>
>> Signed-off-by: Pavel Machek <pavel@xxxxxx>
>>
>> diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
>> index 2795d6d..afb71e0 100644
>> --- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
>> +++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
>> @@ -1016,10 +1016,10 @@ static int atl1c_setup_ring_resources(struct atl1c_adapter *adapter)
>> sizeof(struct atl1c_recv_ret_status) * rx_desc_count +
>> 8 * 4;
>>
>> - ring_header->desc = pci_alloc_consistent(pdev, ring_header->size,
>> - &ring_header->dma);
>> + ring_header->desc = dma_alloc_coherent(&pdev->dev, ring_header->size,
>> + &ring_header->dma, GFP_KERNEL);
>> if (unlikely(!ring_header->desc)) {
>> - dev_err(&pdev->dev, "pci_alloc_consistend failed\n");
>> + dev_err(&pdev->dev, "could not get memory for DMA buffer\n");
>> goto err_nomem;
>> }
>> memset(ring_header->desc, 0, ring_header->size);
>>
>>
>
> So this memset() will really require a different patch to get removed ?
>
> Sigh, not sure why I review patches.

Agreed, please use dma_zalloc_coherent() and kill that memset().

Thanks.
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