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Tue, 03 Feb 2026 08:33:28 -0800 (PST) Message-ID: Date: Tue, 3 Feb 2026 17:33:24 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v4] ppp: enable TX scatter-gather To: Qingfang Deng Cc: Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , linux-ppp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= References: <20260129012902.941-1-dqfext@gmail.com> <03c714f3-edd5-43fb-a0be-8c4a43bf6101@redhat.com> Content-Language: en-US From: Paolo Abeni In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 2/3/26 4:08 PM, Qingfang Deng wrote: > On Tue, Feb 3, 2026 at 6:55 PM Paolo Abeni wrote: >> I'm sorry for missing this point before, but AFAICS channels with >> chan->direct_xmit == 0 do not support GSO packets at all, and here such >> packets will be transmitted after linearization (but still as GSO). >> >> I think that while transmitting over !chan->direct_xmit you additionally >> need to check for GSO packet. If ppp features are recomputed depending >> on the channels configuration, you could chose to drop such packets. >> Otherwise you will need to segment them before transmission, and that >> looks error prone in case of multilink. > > I don't think that's true. Using the current features set (NETIF_F_SG > | NETIF_F_FRAGLIST), the network core will only enable the generic > software GSO (NETIF_F_GSO), and a GSO skb will be segmented in > validate_xmit_skb before being passed to the PPP driver. Right you are! I thought TSO was enabled here at some point but it's not the case. No need to resubmit, let me resurrect this patch in PW. Thanks, Paolo