From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84376C4708C for ; Thu, 1 Dec 2022 09:58:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230427AbiLAJ6S (ORCPT ); Thu, 1 Dec 2022 04:58:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229520AbiLAJ5v (ORCPT ); Thu, 1 Dec 2022 04:57:51 -0500 Received: from mail-wm1-x333.google.com (mail-wm1-x333.google.com [IPv6:2a00:1450:4864:20::333]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B158B9951F for ; Thu, 1 Dec 2022 01:57:22 -0800 (PST) Received: by mail-wm1-x333.google.com with SMTP id i81-20020a1c3b54000000b003d070274a61so3034174wma.3 for ; Thu, 01 Dec 2022 01:57:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=1kx0jr6iQJBdI7n19m8fhu/gw5LbN1tE/Li1THtvucI=; b=KEKMHsEb3yFB2gFZmV6K9MRknX/7TQp8PLqjSDztCIcOZmjK44ShfAtpydvOKHciza LOOZWO4k7ZESZSSOOmpyFlTekAHYODH8gkS4EB8j4Ddz3JrwUFW9Tb1KLmJNXV/j3rVL Sd1EC3kZG/mRFsIF7il3jAJ93BvMwipxG2nbW3xW9TU614kqsmkXhVswBHMLhl4cAq2T CQtcdrDx8btPeUyvtUckJvE0xhkjpZaAH96+TluFpet/yEqQbVhad39RkBOJkfX4Uv2C MbzoUBhTMvq97GMPYwOpRAdw8knSUbLbZv6vnvtWkYEOuYGJupSVgpSI4Vi2FkLRIIMw czdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=1kx0jr6iQJBdI7n19m8fhu/gw5LbN1tE/Li1THtvucI=; b=zVJSEdpjbMM9whIvWxJNrK/5zvHRafY0Jp/ncnA0BpFftiqN2ej6j8Fdaldcu2gTkh nI8MzOy5VwHc+onplPiKHoL7lkjS/MVnjIGuQ2VtJrGaingKvBvNUcaPUFg4SBCa3I3P /S8K6t3KWWyXKnSyrlCEeyx9LmyBWAfHUqu+Rbc7sbfxhCOXUBGxoAKZ6IRto/cOvwSi hxAmlKUgcv7nb5KE0BFPhH7lkllaagEkPAd32fAb6g3kfHdJgkC8rGnPSDVNVe7a+yrv /fU07tb+E90QCZfKEyQapOTIXmpzFPtnvJk6QQqlXmtKswZiW4QMtbxUValCu10iAQ1+ Zvyw== X-Gm-Message-State: ANoB5pkXFoZmTlhIIf9Usz+YIgHZ0OT473uNWTeTaadEjHaoz30WCGNt UiS8a+DzP5ozsxcoiqFt3paHbx34Tr5MB7LafJMuyg== X-Google-Smtp-Source: AA0mqf4RQuT3o5dVODYuifcFa7oAG27rTPoh0EMVG7YVp4qUfFAgO9EocfzkH2534iz0neovTigMa97nRDMKlUjfjG4= X-Received: by 2002:a05:600c:4f05:b0:3d0:3d33:a629 with SMTP id l5-20020a05600c4f0500b003d03d33a629mr24471844wmq.126.1669888641094; Thu, 01 Dec 2022 01:57:21 -0800 (PST) MIME-Version: 1.0 References: <20221124074725.74325-1-haozhe.chang@mediatek.com> In-Reply-To: <20221124074725.74325-1-haozhe.chang@mediatek.com> From: Loic Poulain Date: Thu, 1 Dec 2022 10:56:45 +0100 Message-ID: Subject: Re: [PATCH v5] wwan: core: Support slicing in port TX flow of WWAN subsystem To: haozhe.chang@mediatek.com Cc: M Chetan Kumar , Intel Corporation , Sergey Ryazanov , Johannes Berg , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Stephan Gerhold , Chandrashekar Devegowda , Chiranjeevi Rapolu , Liu Haijun , Ricardo Martinez , Greg Kroah-Hartman , Matthias Brugger , Oliver Neukum , Shang XiaoJing , "open list:INTEL WWAN IOSM DRIVER" , open list , "open list:REMOTE PROCESSOR MESSAGING (RPMSG) WWAN CONTROL..." , "open list:USB SUBSYSTEM" , "moderated list:ARM/Mediatek SoC support" , "moderated list:ARM/Mediatek SoC support" , lambert.wang@mediatek.com, xiayu.zhang@mediatek.com, hua.yang@mediatek.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org On Thu, 24 Nov 2022 at 08:47, wrote: > > From: haozhe chang > > wwan_port_fops_write inputs the SKB parameter to the TX callback of > the WWAN device driver. However, the WWAN device (e.g., t7xx) may > have an MTU less than the size of SKB, causing the TX buffer to be > sliced and copied once more in the WWAN device driver. > > This patch implements the slicing in the WWAN subsystem and gives > the WWAN devices driver the option to slice(by frag_len) or not. By > doing so, the additional memory copy is reduced. > > Meanwhile, this patch gives WWAN devices driver the option to reserve > headroom in fragments for the device-specific metadata. > > Signed-off-by: haozhe chang Reviewed-by: Loic Poulain