Re: [dpdk-dev] [PATCH] net/e1000: do not error out if rx_drop_en is set

["Zhao1, Wei" <wei.zhao1@intel.com>]

Add Qi for discussion.

> -----Original Message-----
> From: Zhao1, Wei
> Sent: Monday, October 8, 2018 4:43 PM
> To: 'Luca Boccassi' <bluca@debian.org>; dev@dpdk.org
> Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; stable@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH] net/e1000: do not error out if rx_drop_en is
> set
> 
> Hi,  Luca Boccassi
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Luca Boccassi
> > Sent: Saturday, July 28, 2018 1:26 AM
> > To: dev@dpdk.org
> > Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Luca Boccassi
> > <bluca@debian.org>; stable@dpdk.org
> > Subject: [dpdk-dev] [PATCH] net/e1000: do not error out if rx_drop_en
> > is set
> >
> > rx_drop_en is an optimization that does nothing on single-queue
> > devices like e1000. Do not force applications that do not care to
> > select per-devices
> 
> And aslo, eth_em_rx_queue_setup support set up of multiple queues for
> EM device.
> 
> > optimizations flags by returning an error, just log it and carry on.
> 
> rx_drop_en is a flag to enable receive packets drop when insufficient receive
> descriptors exist to write the packet into system memory.
> if we delete this parameter check protection, it may be misleading some
> applications for this point, why does not give some requirement for proper
> usage of this? I do not suggest for this change.
> You can also refer to function eth_igb_rx_queue_setup(), igb device support
> rx_drop_en set, so we do not have a such parameter check.
> 
> >
> > Fixes: 805803445a02 ("e1000: support EM devices (also known as
> > e1000/e1000e)")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Luca Boccassi <bluca@debian.org>
> > ---
> >  drivers/net/e1000/em_rxtx.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/e1000/em_rxtx.c b/drivers/net/e1000/em_rxtx.c
> > index a6b3e92a6..81dc41efb 100644
> > --- a/drivers/net/e1000/em_rxtx.c
> > +++ b/drivers/net/e1000/em_rxtx.c
> > @@ -1416,12 +1416,13 @@ eth_em_rx_queue_setup(struct rte_eth_dev
> *dev,
> >  	}
> >
> >  	/*
> > -	 * EM devices don't support drop_en functionality
> > +	 * EM devices don't support drop_en functionality.
> > +	 * It's an optimization that does nothing on single-queue devices,
> > +	 * so just log the issue and carry on.
> >  	 */
> >  	if (rx_conf->rx_drop_en) {
> > -		PMD_INIT_LOG(ERR, "drop_en functionality not supported
> > by "
> > +		PMD_INIT_LOG(NOTICE, "drop_en functionality not
> > supported by "
> >  			     "device");
> > -		return -EINVAL;
> >  	}
> >
> >  	/* Free memory prior to re-allocation if needed. */
> > --
> > 2.18.0