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([2620:10d:c090:500::5ae7]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2ca7c20b195sm13283913eec.16.2026.04.06.11.30.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Apr 2026 11:30:05 -0700 (PDT) Message-ID: <6796586f-18ce-49d1-99d9-c3c5df72bcf3@gmail.com> Date: Mon, 6 Apr 2026 11:30:02 -0700 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v6 7/7] net: bcmgenet: reject MTU changes incompatible with XDP To: Nicolai Buchwitz , netdev@vger.kernel.org Cc: Justin Chen , Simon Horman , Doug Berger , Florian Fainelli , Broadcom internal kernel review list , Andrew Lunn , Eric Dumazet , Paolo Abeni , "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , linux-kernel@vger.kernel.org, bpf@vger.kernel.org References: <20260406083536.839517-1-nb@tipi-net.de> <20260406083536.839517-8-nb@tipi-net.de> Content-Language: en-US From: Mohsin Bashir In-Reply-To: <20260406083536.839517-8-nb@tipi-net.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit > > +static int bcmgenet_change_mtu(struct net_device *dev, int new_mtu) > +{ > + struct bcmgenet_priv *priv = netdev_priv(dev); > + > + if (priv->xdp_prog && new_mtu > PAGE_SIZE - GENET_RX_HEADROOM - > + SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) { > + netdev_warn(dev, "MTU too large for single-page XDP buffer\n"); > + return -EINVAL; > + } > + > + WRITE_ONCE(dev->mtu, new_mtu); > + return 0; > +} > + > static const struct net_device_ops bcmgenet_netdev_ops = { > .ndo_open = bcmgenet_open, > .ndo_stop = bcmgenet_close, > @@ -4102,6 +4116,7 @@ static const struct net_device_ops bcmgenet_netdev_ops = { > .ndo_eth_ioctl = phy_do_ioctl_running, > .ndo_set_features = bcmgenet_set_features, > .ndo_get_stats64 = bcmgenet_get_stats64, > + .ndo_change_mtu = bcmgenet_change_mtu, > .ndo_change_carrier = bcmgenet_change_carrier, > .ndo_bpf = bcmgenet_xdp, > .ndo_xdp_xmit = bcmgenet_xdp_xmit, Reviewed-by: Mohsin Bashir