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Date: Wed, 27 Mar 2024 06:51:25 -0700
From: Breno Leitao <leitao@debian.org>
To: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: rbc@meta.com, riel@surriel.com,
	"open list:VIRTIO CORE AND NET DRIVERS" <virtualization@lists.linux.dev>,
	"open list:NETWORKING DRIVERS" <netdev@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>, hengqi@linux.alibaba.com,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH net v2 1/2] virtio_net: Do not set rss_indir if RSS is
 not supported
Message-ID: <ZgQkXfMd6GIEndXm@gmail.com>
References: <20240326151911.2155689-1-leitao@debian.org>
 <1711503463.632461-1-xuanzhuo@linux.alibaba.com>
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In-Reply-To: <1711503463.632461-1-xuanzhuo@linux.alibaba.com>

Hello Xuan,

On Wed, Mar 27, 2024 at 09:37:43AM +0800, Xuan Zhuo wrote:
> On Tue, 26 Mar 2024 08:19:08 -0700, Breno Leitao <leitao@debian.org> wrote:
> > Do not set virtnet_info->rss_indir_table_size if RSS is not available
> > for the device.
> >
> > Currently, rss_indir_table_size is set if either has_rss or
> > has_rss_hash_report is available, but, it should only be set if has_rss
> > is set.
> >
> > On the virtnet_set_rxfh(), return an invalid command if the request has
> > indirection table set, but virtnet does not support RSS.
> >
> > Suggested-by: Heng Qi <hengqi@linux.alibaba.com>
> > Signed-off-by: Breno Leitao <leitao@debian.org>
> > ---
> >  drivers/net/virtio_net.c | 9 +++++++--
> >  1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index c22d1118a133..c640fdf28fc5 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -3813,6 +3813,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
> >  	    rxfh->hfunc != ETH_RSS_HASH_TOP)
> >  		return -EOPNOTSUPP;
> >
> > +	if (rxfh->indir && !vi->has_rss)
> > +		return -EINVAL;
> > +
> >  	if (rxfh->indir) {
> 
> Put !vi->has_rss here?

I am not sure I understand the suggestion. Where do you suggest we have
!vi->has_rss?

If we got this far, we either have:

a) rxfh->indir set and vi->has_rss is also set
b) rxfh->indir not set. (vi->has_rss could be set or not).

Thanks for the review,
Breno