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

[Noa Ezra]

Hi,

> -----Original Message-----
> From: Maxime Coquelin [mailto:maxime.coquelin at redhat.com]
> Sent: Tuesday, June 25, 2019 11:24 AM
> To: Noa Ezra <noae at mellanox.com>
> Cc: Matan Azrad <matan at mellanox.com>; dev at dpdk.org; stable at dpdk.org
> Subject: Re: [Suspected-Phishing][PATCH] net/vhost: fix redundant queue
> state event
> 
> 
> 
> 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 at mellanox.com]
> >> Sent: Wednesday, June 19, 2019 9:16 AM
> >> To: maxime.coquelin at redhat.com
> >> Cc: Matan Azrad <matan at mellanox.com>; dev at dpdk.org; Noa Ezra
> >> <noae at mellanox.com>; stable at 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 at dpdk.org
> >> Reviewed-by: Matan Azrad <matan at 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?

Can you please look again? As I understand it, "enable" is the "new state" parameter (can be enable/disable).
In this fix I make sure that there was really a change in the state before calling EVENT_QUEUE_STATE (with no change in the state).

> 
> >> --
> >> 1.8.3.1
> >