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[144.49.247.15]) by smtp-relay.gmail.com with ESMTPS id 00721157ae682-79cb7f07e45sm7083477b3.11.2026.03.30.15.06.09 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Mar 2026 15:06:10 -0700 (PDT) X-Relaying-Domain: broadcom.com X-CFilter-Loop: Reflected Received: by mail-dy1-f198.google.com with SMTP id 5a478bee46e88-2ba9a744f7dso5266373eec.0 for ; Mon, 30 Mar 2026 15:06:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; t=1774908369; x=1775513169; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=wazMMCQ25eiP79G9aIROHWVXvvxGSf4JuL+1u5LyYKw=; b=P4X5DeVZU6t2nP/KyI6c8nBmLY2DXHH8ZYx9YoqLFMp2vaDEWjvWbc40Fqn+gx/qlp GfPaB7vmWeGLEaUUEM8I+zeqZjD+XNFg7CCT95nP4YRqEXDbnmZiSCQ5YNXtPqm/qXbT dxHaGwl0UDm0n/5KmozkwOyCtQZEs0HzOE7RY= X-Forwarded-Encrypted: i=1; AJvYcCWVc90iRA6ip1DJM96zr2q6hytP+acX9E5QU1XUMvdBVkybd7Y2wIt/MIJ0Pxv85X+ztTFwm8f2Pi+2Ejo=@vger.kernel.org X-Received: by 2002:a05:693c:310c:b0:2c6:cdb3:bd67 with SMTP id 5a478bee46e88-2c6cdc30cd2mr2625850eec.22.1774908368708; Mon, 30 Mar 2026 15:06:08 -0700 (PDT) X-Received: by 2002:a05:693c:310c:b0:2c6:cdb3:bd67 with SMTP id 5a478bee46e88-2c6cdc30cd2mr2625818eec.22.1774908368152; Mon, 30 Mar 2026 15:06:08 -0700 (PDT) Received: from [10.67.48.245] ([192.19.223.252]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2c3c68b249fsm8196653eec.19.2026.03.30.15.06.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 30 Mar 2026 15:06:07 -0700 (PDT) Message-ID: <99062602-05a3-418f-9182-f60a83fdbe3b@broadcom.com> Date: Mon, 30 Mar 2026 15:06:05 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v3 3/6] net: bcmgenet: add basic XDP support (PASS/DROP) To: Nicolai Buchwitz , Mohsin Bashir Cc: netdev@vger.kernel.org, Doug Berger , Broadcom internal kernel review list , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , linux-kernel@vger.kernel.org, bpf@vger.kernel.org References: <20260319115402.353509-1-nb@tipi-net.de> <20260319115402.353509-4-nb@tipi-net.de> <1d551008-3c42-4b7b-9507-03072740a54a@gmail.com> <56270d59e5e5e79fcd3d104817679d70@tipi-net.de> Content-Language: en-US, fr-FR From: Florian Fainelli Autocrypt: addr=florian.fainelli@broadcom.com; keydata= xsBNBFPAG8ABCAC3EO02urEwipgbUNJ1r6oI2Vr/+uE389lSEShN2PmL3MVnzhViSAtrYxeT M0Txqn1tOWoIc4QUl6Ggqf5KP6FoRkCrgMMTnUAINsINYXK+3OLe7HjP10h2jDRX4Ajs4Ghs JrZOBru6rH0YrgAhr6O5gG7NE1jhly+EsOa2MpwOiXO4DE/YKZGuVe6Bh87WqmILs9KvnNrQ PcycQnYKTVpqE95d4M824M5cuRB6D1GrYovCsjA9uxo22kPdOoQRAu5gBBn3AdtALFyQj9DQ KQuc39/i/Kt6XLZ/RsBc6qLs+p+JnEuPJngTSfWvzGjpx0nkwCMi4yBb+xk7Hki4kEslABEB AAHNMEZsb3JpYW4gRmFpbmVsbGkgPGZsb3JpYW4uZmFpbmVsbGlAYnJvYWRjb20uY29tPsLB IQQQAQgAywUCZWl41AUJI+Jo+hcKAAG/SMv+fS3xUQWa0NryPuoRGjsA3SAUAAAAAAAWAAFr ZXktdXNhZ2UtbWFza0BwZ3AuY29tjDAUgAAAAAAgAAdwcmVmZXJyZWQtZW1haWwtZW5jb2Rp bmdAcGdwLmNvbXBncG1pbWUICwkIBwMCAQoFF4AAAAAZGGxkYXA6Ly9rZXlzLmJyb2FkY29t Lm5ldAUbAwAAAAMWAgEFHgEAAAAEFQgJChYhBNXZKpfnkVze1+R8aIExtcQpvGagAAoJEIEx tcQpvGagWPEH/2l0DNr9QkTwJUxOoP9wgHfmVhqc0ZlDsBFv91I3BbhGKI5UATbipKNqG13Z TsBrJHcrnCqnTRS+8n9/myOF0ng2A4YT0EJnayzHugXm+hrkO5O9UEPJ8a+0553VqyoFhHqA zjxj8fUu1px5cbb4R9G4UAySqyeLLeqnYLCKb4+GklGSBGsLMYvLmIDNYlkhMdnnzsSUAS61 WJYW6jjnzMwuKJ0ZHv7xZvSHyhIsFRiYiEs44kiYjbUUMcXor/uLEuTIazGrE3MahuGdjpT2 IOjoMiTsbMc0yfhHp6G/2E769oDXMVxCCbMVpA+LUtVIQEA+8Zr6mX0Yk4nDS7OiBlvOwE0E U8AbwQEIAKxr71oqe+0+MYCc7WafWEcpQHFUwvYLcdBoOnmJPxDwDRpvU5LhqSPvk/yJdh9k 4xUDQu3rm1qIW2I9Puk5n/Jz/lZsqGw8T13DKyu8eMcvaA/irm9lX9El27DPHy/0qsxmxVmU pu9y9S+BmaMb2CM9IuyxMWEl9ruWFS2jAWh/R8CrdnL6+zLk60R7XGzmSJqF09vYNlJ6Bdbs MWDXkYWWP5Ub1ZJGNJQ4qT7g8IN0qXxzLQsmz6tbgLMEHYBGx80bBF8AkdThd6SLhreCN7Uh IR/5NXGqotAZao2xlDpJLuOMQtoH9WVNuuxQQZHVd8if+yp6yRJ5DAmIUt5CCPcAEQEAAcLB gQQYAQIBKwUCU8AbwgUbDAAAAMBdIAQZAQgABgUCU8AbwQAKCRCTYAaomC8PVQ0VCACWk3n+ obFABEp5Rg6Qvspi9kWXcwCcfZV41OIYWhXMoc57ssjCand5noZi8bKg0bxw4qsg+9cNgZ3P N/DFWcNKcAT3Z2/4fTnJqdJS//YcEhlr8uGs+ZWFcqAPbteFCM4dGDRruo69IrHfyyQGx16s CcFlrN8vD066RKevFepb/ml7eYEdN5SRALyEdQMKeCSf3mectdoECEqdF/MWpfWIYQ1hEfdm C2Kztm+h3Nkt9ZQLqc3wsPJZmbD9T0c9Rphfypgw/SfTf2/CHoYVkKqwUIzI59itl5Lze+R5 wDByhWHx2Ud2R7SudmT9XK1e0x7W7a5z11Q6vrzuED5nQvkhAAoJEIExtcQpvGagugcIAJd5 EYe6KM6Y6RvI6TvHp+QgbU5dxvjqSiSvam0Ms3QrLidCtantcGT2Wz/2PlbZqkoJxMQc40rb fXa4xQSvJYj0GWpadrDJUvUu3LEsunDCxdWrmbmwGRKqZraV2oG7YEddmDqOe0Xm/NxeSobc MIlnaE6V0U8f5zNHB7Y46yJjjYT/Ds1TJo3pvwevDWPvv6rdBeV07D9s43frUS6xYd1uFxHC 7dZYWJjZmyUf5evr1W1gCgwLXG0PEi9n3qmz1lelQ8lSocmvxBKtMbX/OKhAfuP/iIwnTsww 95A2SaPiQZA51NywV8OFgsN0ITl2PlZ4Tp9hHERDe6nQCsNI/Us= In-Reply-To: <56270d59e5e5e79fcd3d104817679d70@tipi-net.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e On 3/30/26 15:01, Nicolai Buchwitz wrote: > On 30.3.2026 20:15, Mohsin Bashir wrote: >>> +static int bcmgenet_xdp_setup(struct net_device *dev, >>> +                  struct netdev_bpf *xdp) >>> +{ >>> +    struct bcmgenet_priv *priv = netdev_priv(dev); >>> +    struct bpf_prog *old_prog; >>> +    struct bpf_prog *prog = xdp->prog; >>> + >>> +    if (prog && dev->mtu > PAGE_SIZE - GENET_RX_HEADROOM - >>> +        SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) { >>> +        NL_SET_ERR_MSG_MOD(xdp->extack, >>> +                   "MTU too large for single-page XDP buffer"); >>> +        return -EOPNOTSUPP; >>> +    } >> >> The MTU check here is great. But I do not see support >> for .ndo_change_mtu. This would allow users to change MTU size AFTER >> the program is attached. > > Good point. I had planned to add ndo_change_mtu in a follow-up series, > but this leaves a gap where MTU can be changed while XDP is attached. > > Options: > 1. Add a minimal ndo_change_mtu to this series that only rejects MTU > changes incompatible with XDP, default behavior otherwise Option 1 seems to be the simplest yet getting you a path through merging XDP support. > 2. Reject any MTU change while XDP is attached > 3. Defer to the ndo_change_mtu follow-up series > > Thoughts? > > Thanks > Nicolai -- Florian