Re: [dpdk-dev] [Suspected-Phishing][PATCH] net/vhost: fix redundant queue state event

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 6/25/19 9:04 AM, Noa Ezra wrote:
> Hi,
> What do you think about this patch?
> 
> Thanks,
> Noa.
> 
>> -----Original Message-----
>> From: Noa Ezra [mailto:noae@mellanox.com]
>> Sent: Wednesday, June 19, 2019 9:16 AM
>> To: maxime.coquelin@redhat.com
>> Cc: Matan Azrad <matan@mellanox.com>; dev@dpdk.org; Noa Ezra
>> <noae@mellanox.com>; stable@dpdk.org
>> Subject: [Suspected-Phishing][PATCH] net/vhost: fix redundant queue state
>> event
>>
>> In some situations, when a virtual machine is starting, vring_state_changed
>> can be called while there was no change in the queue state. This fix makes
>> sure that there was really a change in the queue state before calling the
>> callback for EVENT_QUEUE_STATE.
>>
>> Fixes: ee584e9710b9 ("vhost: add driver on top of the library")
>> Cc: stable@dpdk.org
>> Reviewed-by: Matan Azrad <matan@mellanox.com>
>> ---
>>   drivers/net/vhost/rte_eth_vhost.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/net/vhost/rte_eth_vhost.c
>> b/drivers/net/vhost/rte_eth_vhost.c
>> index cad1e5c..fbe7a37 100644
>> --- a/drivers/net/vhost/rte_eth_vhost.c
>> +++ b/drivers/net/vhost/rte_eth_vhost.c
>> @@ -855,6 +855,10 @@ struct vhost_xstats_name_off {
>>   	/* won't be NULL */
>>   	state = vring_states[eth_dev->data->port_id];
>>   	rte_spinlock_lock(&state->lock);
>> +	if (state->cur[vring] == enable) {
>> +		rte_spinlock_unlock(&state->lock);
>> +		return 0;
>> +	}
>>
>>   	state->cur[vring] = enable;
>>   	state->max_vring = RTE_MAX(vring, state->max_vring);

Maybe the application would want to be notified a new queue is
available, even if it is disabled?

>> --
>> 1.8.3.1
>