Re: [PATCH v6 4/9] bgmac: simplify/optimize rx DMA error handling

["Rafał Miłecki" <zajec5@gmail.com>]

On 14 April 2015 at 11:13, Felix Fietkau <nbd@openwrt.org> wrote:
> On 2015-04-14 07:55, Rafał Miłecki wrote:
>> On 14 April 2015 at 01:42, Felix Fietkau <nbd@openwrt.org> wrote:
>>> @@ -528,14 +524,14 @@ static void bgmac_dma_rx_ring_free(struct bgmac *bgmac,
>>>
>>>         for (i = 0; i < ring->num_slots; i++) {
>>>                 slot = &ring->slots[i];
>>> -               if (!slot->buf)
>>> +               if (!slot->dma_addr)
>>>                         continue;
>>
>> I think it breaks error path of bgmac_dma_alloc. It may happen that
>> during DMA alloc we alloc skb and then we fail to map it. In such case
>> buf should be freed. Please trace how bgmac_dma_free is used in
>> bgmac_dma_alloc.
> I don't think so: bgmac_dma_rx_skb_for_slot handles both buffer
> allocation and dma mapping. If dma mapping fails, the buffer is freed
> before any part of the slot is overwritten.

Oops, I think I just spotted a memory leak then.

If bgmac_dma_rx_skb_for_slot fails to do DMA mapping it returns an
error without freeing a skb.

-- 
Rafał