[dpdk-dev] [PATCH 09/13] net/hns3: fix maximum frame size update after buffer alloc

[oulijun]

在 2021/2/26 23:25, Ferruh Yigit 写道:
> On 2/24/2021 1:28 AM, Lijun Ou wrote:
>> From: Chengchang Tang <tangchengchang at huawei.com>
>>
>> After MTU changed, the buffer used to store packets in HW should be
>> reallocated. And buffer size is allocated based on the maximum frame
>> size in the PF struct. However, the value of maximum frame size  is
>> not updated in time when MTU is changed. This would lead to a packet
>> loss for not enough buffer.
>>
>> This patch update the maximum frame size before reallocating the HW
>> buffer. And a rollback operation is added to avoid the side effects
>> of buffer reallocation failures.
>>
>> Fixes: 1f5ca0b460cd ("net/hns3: support some device operations")
>> Fixes: d51867db65c1 ("net/hns3: add initialization")
>> Cc: stable at dpdk.org
>>
>> Signed-off-by: Chengchang Tang <tangchengchang at huawei.com>
>> Signed-off-by: Lijun Ou <oulijun at huawei.com>
> 
> Isn't the patch title should say 'before', like:
> net/hns3: fix maximum frame size update _before_ buffer alloc
> 
> Or perhaps I get the patch wrong...
> .

The expression here may vary from different perspectives. From a 
hardware standpoint, the problem is that the maximum frame size update 
buffer allocation. From a software standpoint, the the buffer size that 
should be allocted depends on the maximum frame size kept in the driver, 
and the problem is caused by the late value update in the driver.
>