netdev - Re: [PATCH net-next v2] bnxt_en: Allow ntuple filters for drops

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Message-ID: <aX1N8UfZ4I+8ZTii@devvm20253.cco0.facebook.com>
Date: Fri, 30 Jan 2026 16:33:53 -0800
From: Joe Damato <joe@...a.to>
To: Michael Chan <michael.chan@...adcom.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	Pavan Chebbi <pavan.chebbi@...adcom.com>,
	Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	shruti.parab@...adcom.com
Subject: Re: [PATCH net-next v2] bnxt_en: Allow ntuple filters for drops

On Thu, Jan 29, 2026 at 06:28:38PM -0800, Michael Chan wrote:
> On Thu, Jan 29, 2026 at 4:23 PM Joe Damato <joe@...a.to> wrote:
> >
> > It appears that in commit 7efd79c0e689 ("bnxt_en: Add drop action
> > support for ntuple"), bnxt gained support for ntuple filters for packet
> > drops.
> >
> > However, support for this does not seem to work in recent kernels or
> > against net-next:
> >
> >   % sudo ethtool -U eth0 flow-type udp4 src-ip 1.1.1.1 action -1
> >     rmgr: Cannot insert RX class rule: Operation not supported
> >     Cannot insert classification rule
> >
> > The issue is that the existing code uses ethtool_get_flow_spec_ring_vf,
> > which will return a non-zero value if the ring_cookie is set to
> > RX_CLS_FLOW_DISC, which then causes bnxt_add_ntuple_cls_rule to return
> > -EOPNOTSUPP because it thinks the user is trying to set an ntuple filter
> > for a vf.
> >
> > Fix this by first checking that the ring_cookie is not RX_CLS_FLOW_DISC.
> >
> > After this patch, ntuple filters for drops can be added:
> >
> >   % sudo ethtool -U eth0 flow-type udp4 src-ip 1.1.1.1 action -1
> >   Added rule with ID 0
> >
> >   % ethtool -n eth0
> >   44 RX rings available
> >   Total 1 rules
> >
> >   Filter: 0
> >       Rule Type: UDP over IPv4
> >       Src IP addr: 1.1.1.1 mask: 0.0.0.0
> >       Dest IP addr: 0.0.0.0 mask: 255.255.255.255
> >       TOS: 0x0 mask: 0xff
> >       Src port: 0 mask: 0xffff
> >       Dest port: 0 mask: 0xffff
> >       Action: Drop
> >
> > Signed-off-by: Joe Damato <joe@...a.to>
> > ---
> > v2:
> >   - Extract the FLOW_MAC_EXT and FLOW_EXT check so it happens unconditionally.
> >   - Eliminate the local variable ring, which was used in only one place and
> >     call ethtool_get_flow_spec_ring instead.
> >
> > v1: https://lore.kernel.org/netdev/20260128222718.1679581-1-joe@dama.to/
> 
> One minor improvement is to eliminate the vf variable since it is also
> used only once.  But I'm fine with this patch.  Thanks.
> 
> Reviewed-by: Michael Chan <michael.chan@...adcom.com>

I made the improvement you suggested in the v3 I just sent. I retained your
tag because the suggestion was cosmetic; I hope that's OK.