Re: [PATCH net-next] drivers: net: xgene: Fix dma_unmap_single() size

[Thomas Fourier <fourier.thomas@gmail.com>]

Hi Daniel,
> Hi Thomas,
> 
>> In xgene_enet_refill_pagepool(), the skb->data is dma-mapped with length
> 
> To me, it looks like the mapping happens in xgene_enet_refill_bufpool() and not
> xgene_enet_refill_pagepool().>
>> len which is set to XGENE_ENET_STD_MTU which equals 1536. However, in
>> xgene_enet_delete_bufpool(), the same buffer is unmapped with length
>> XGENE_ENET_MAX_MTU which is 9600. This may erroneously unmap other
>> DMA buffers or cause other issues.
>>
>> Change unmap length to XGENE_ENET_STD_MTU.
>>
>> Fixes: 6e434627bce2 ("drivers: net: xgene: fix: Add dma_unmap_single")
> 
> That commit mapped and unmapped with XGENE_ENET_MAX_MTU. At that point, there
> was no mismatch. I think the mismatch came with:
> 
> Fixes: a9380b0f7be8 ("drivers: net: xgene: Add support for Jumbo frame")
> 
>> Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
>> ---
>>   drivers/net/ethernet/apm/xgene/xgene_enet_main.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
>> index 507db46daf2b..2ddcbf27014e 100644
>> --- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
>> +++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
>> @@ -185,7 +185,7 @@ static void xgene_enet_delete_bufpool(struct xgene_enet_desc_ring *buf_pool)
>>   
>>   			raw_desc = &buf_pool->raw_desc16[i];
>>   			dma_addr = GET_VAL(DATAADDR, le64_to_cpu(raw_desc->m1));
>> -			dma_unmap_single(dev, dma_addr, XGENE_ENET_MAX_MTU,
>> +			dma_unmap_single(dev, dma_addr, XGENE_ENET_STD_MTU,
>>   					 DMA_FROM_DEVICE);
>>   		}
>>   	}
>> -- 
>> 2.53.0
>>
> 
> /Daniel

Thank you for your comments, I agree with both, I am submitting a v2.
Best,
Thomas