[dpdk-dev] [PATCH] net: virtio: clear reserved vring properly at setup time

Maxime Coquelin maxime.coquelin at redhat.com
Tue Jul 19 07:31:35 CEST 2016



On 07/19/2016 03:39 AM, Yuanhan Liu wrote:
> On Mon, Jul 18, 2016 at 07:09:24PM +0200, Maxime Coquelin wrote:
>> After vring reservation, only the first bytes of the vring were
>> cleared.
>>
>> This patch fixes this to clear the real size fo the vring.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>> ---
>>
>> Note: I found this bug while doing some code review,
>
> Nice catch!
>
>> it is not a fix for
>> a problem I encountered.
>
> Yes, there should be no problem: vring memory is completely zero-ed
> at port start stage by virtio_dev_vring_start().

Ok, thanks for the pointer.

>
>> ---
>>  drivers/net/virtio/virtio_ethdev.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
>> index 850e3ba..336b3fc 100644
>> --- a/drivers/net/virtio/virtio_ethdev.c
>> +++ b/drivers/net/virtio/virtio_ethdev.c
>> @@ -387,7 +387,7 @@ int virtio_dev_queue_setup(struct rte_eth_dev *dev,
>>  		}
>>  	}
>>
>> -	memset(mz->addr, 0, sizeof(mz->len));
>> +	memset(mz->addr, 0, mz->len);
>
> Actually, I think we could simply drop the memset here. It's redundant,
> as stated.
We can skip this patch then.

>
> And to Thomas, I don't find a good reason to have this in 16.07. Let's
> delay the apply to v16.11.
Yes, that's why I mentioned it didn't fixed any problem on my side.

So I propose we skip this patch, I'll resend one removing the memset for 
v16.11.

Thanks,
Maxime

>
> 	--yliu
>
>>  	vq->vq_ring_mem = mz->phys_addr;
>>  	vq->vq_ring_virt_mem = mz->addr;
>> --
>> 2.7.4


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