[ovs-dev] [PATCH 1/2] netdev-dpdk: Restore txq/rxq number if initialization fails.

[Ethan Jackson]

Would you please summarize the errors on list?  Daniele should
probably have a look at it since he wrote the patch originally.

Ethan

On Thu, Jul 23, 2015 at 4:27 PM, Luis E Pena <lpena at vmware.com> wrote:
> I ran into errors when using master when adding a dpdk port. I worked with Pravin yesterday and we think that the cause is this patch.
> When we tried branch-2.4, we ran into no errors.
>  Today I am working on confirming that this is the patch.
>
> Luis E. P.
>
> Sent from my iPhone
>
>> On Jul 23, 2015, at 15:38, Ethan Jackson <ethan at nicira.com> wrote:
>>
>> Ben, Justin, should this be backported?  I'm not up on the policy at the moment.
>>
>> Etha
>>
>>> On Thu, Jul 23, 2015 at 3:42 AM, Traynor, Kevin <kevin.traynor at intel.com> wrote:
>>>
>>>> -----Original Message-----
>>>> From: dev [mailto:dev-bounces at openvswitch.org] On Behalf Of Daniele Di
>>>> Proietto
>>>> Sent: Thursday, July 16, 2015 7:48 PM
>>>> To: dev at openvswitch.org
>>>> Subject: [ovs-dev] [PATCH 1/2] netdev-dpdk: Restore txq/rxq number if
>>>> initialization fails.
>>>>
>>>> netdev_dpdk_set_multiq() should not set the number of configured rxq
>>>> and txq if the driver initialization fails (meaning that the driver
>>>> failed to setup the queues).  Otherwise, on a subsequent call to
>>>> netdev_dpdk_set_multiq(), the code may believe that the queues have
>>>> already been setup and there's no work to be done.
>>>>
>>>> This commit fixes the problem by restoring the old values if
>>>> dpdk_eth_dev_init() fails.
>>>>
>>>> Reported-by: Ian Stokes <ian.stokes at intel.com>
>>>> Signed-off-by: Daniele Di Proietto <diproiettod at vmware.com>
>>>> ---
>>>> lib/netdev-dpdk.c | 9 +++++++++
>>>> 1 file changed, 9 insertions(+)
>>>>
>>>> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
>>>> index 8b843db..5ae805e 100644
>>>> --- a/lib/netdev-dpdk.c
>>>> +++ b/lib/netdev-dpdk.c
>>>> @@ -743,6 +743,7 @@ netdev_dpdk_set_multiq(struct netdev *netdev_, unsigned
>>>> int n_txq,
>>>> {
>>>>     struct netdev_dpdk *netdev = netdev_dpdk_cast(netdev_);
>>>>     int err = 0;
>>>> +    int old_rxq, old_txq;
>>>>
>>>>     if (netdev->up.n_txq == n_txq && netdev->up.n_rxq == n_rxq) {
>>>>         return err;
>>>> @@ -753,12 +754,20 @@ netdev_dpdk_set_multiq(struct netdev *netdev_, unsigned
>>>> int n_txq,
>>>>
>>>>     rte_eth_dev_stop(netdev->port_id);
>>>>
>>>> +    old_txq = netdev->up.n_txq;
>>>> +    old_rxq = netdev->up.n_rxq;
>>>>     netdev->up.n_txq = n_txq;
>>>>     netdev->up.n_rxq = n_rxq;
>>>>
>>>>     rte_free(netdev->tx_q);
>>>>     err = dpdk_eth_dev_init(netdev);
>>>>     netdev_dpdk_alloc_txq(netdev, netdev->real_n_txq);
>>>> +    if (err) {
>>>> +        /* If there has been an error, it means that the requested queues
>>>> +         * have not been created.  Restore the old numbers. */
>>>> +        netdev->up.n_txq = old_txq;
>>>> +        netdev->up.n_rxq = old_rxq;
>>>
>>> I had thought that we should restore the previous netdev->tx_q but at present
>>> txq's are fixed, so I think it is fine. If txq's become configurable we can change.
>>>
>>> It would be good to get these patches into OVS2.4 branch if there is still time?
>>>
>>> Acked-by: Kevin Traynor <kevin.traynor at intel.com>
>>>
>>>> +    }
>>>>
>>>>     netdev->txq_needs_locking = netdev->real_n_txq != netdev->up.n_txq;
>>>>
>>>> --
>>>> 2.1.4
>>>>
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