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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51FCAC433DF for ; Thu, 15 Oct 2020 10:20:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CAEF02224A for ; Thu, 15 Oct 2020 10:20:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="OUinwxwm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727973AbgJOKUR (ORCPT ); Thu, 15 Oct 2020 06:20:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726709AbgJOKUQ (ORCPT ); Thu, 15 Oct 2020 06:20:16 -0400 Received: from mail-ej1-x643.google.com (mail-ej1-x643.google.com [IPv6:2a00:1450:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 362A6C061755 for ; Thu, 15 Oct 2020 03:20:16 -0700 (PDT) Received: by mail-ej1-x643.google.com with SMTP id ce10so2821102ejc.5 for ; Thu, 15 Oct 2020 03:20:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=h8VwUpwBBTh1Rt5wZETtbVn2OaoNXb3XoyRsN7+Y0Go=; b=OUinwxwmMVvHZNml5LaB5PTPpU9i/RuDDwuzA61t8sa5dwIEidyVF5r0y+c92yC7XG cdj7xvaeqCjhVzsrsZAGUceg/sZZyyWdN4vIs7bzOES1xH3d3GZb9JuqitYgrXvM7m/p RJIAvbnfWIAAzo4wGGeS6qeOK8wiM8+j365oxnSJQXbH7WBJJ0eAcTeEtyOMLyEA/sAw /wy/wDs6ueLWwtk9GdlXcG2VT2rYUzdYcLs9Tw4Bi1rsfaBMcdcRq0QJfmqB4eu/z5qz oABNBu8ZvkApKzH/coefXH/ngxzc8opNH3YE6bRdy03/3ZFaguRutlbZ1W1nBdyhQvi+ 8UEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=h8VwUpwBBTh1Rt5wZETtbVn2OaoNXb3XoyRsN7+Y0Go=; b=W03i/FTVnxX9JQK/2j9eJoFzwr1Km47bIpPgzIfGr7YBGifJeXTumTALcd0xk+iHMh EcqBdag1hHnms66TXdrd2rtYuvNeiKfGH+riTw8plnnywdF9ieyZ+XYnmhQTvRr5LUSp F46coLR+EgKSyhIh69mN3ZwpGrFKjJaPc6YyyYTZBvb47OCaZ2FSzxcjBHT2EpKQ9HYU Uiyasm143bCFd+jCl2ZxMP5uUUeB9YxUO3RfZTGgalg3/1dLXh6gXyqDLDC6aQwQn1Tz N+uDFxr69V2J7WfY+nDTOhAUKjhVd4NZd5zhCxULy+9RM3r1sf0YMf2MjWp6tCQPnb38 GHzw== X-Gm-Message-State: AOAM531Dm4sVMET9L2byRbc+evncwYs348DxA1KHvnhWaT6SifRtTqUI jZsFFFDdp7dFKlcHfXBZFwyxk0XBMo/clgsY/RES7A== X-Google-Smtp-Source: ABdhPJx5+mUYrRfq/cJ5vkeB4PPpgw3U7SUSOp+iKzMy158tSj/eykJP7DB8v/ac6bkyUbqxNvjJYamh4Wd/GTvEJUA= X-Received: by 2002:a17:906:1f53:: with SMTP id d19mr3537700ejk.255.1602757214763; Thu, 15 Oct 2020 03:20:14 -0700 (PDT) MIME-Version: 1.0 References: <1602676437-9829-1-git-send-email-loic.poulain@linaro.org> In-Reply-To: From: Loic Poulain Date: Thu, 15 Oct 2020 12:25:44 +0200 Message-ID: Subject: Re: [PATCH v3] net: Add mhi-net driver To: Eric Dumazet Cc: davem@davemloft.net, Jakub Kicinski , netdev@vger.kernel.org, Hemant Kumar , Manivannan Sadhasivam Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 15 Oct 2020 at 09:25, Eric Dumazet wrote: > > > > On 10/14/20 1:53 PM, Loic Poulain wrote: > > This patch adds a new network driver implementing MHI transport for > > network packets. Packets can be in any format, though QMAP (rmnet) > > is the usual protocol (flow control + PDN mux). > > > > ... > > > +static void mhi_net_rx_refill_work(struct work_struct *work) > > +{ > > + struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev, > > + rx_refill.work); > > + struct net_device *ndev = mhi_netdev->ndev; > > + struct mhi_device *mdev = mhi_netdev->mdev; > > + struct sk_buff *skb; > > + int err; > > + > > + do { > > + skb = netdev_alloc_skb(ndev, READ_ONCE(ndev->mtu)); > > + if (unlikely(!skb)) > > + break; > > It is a bit strange you use READ_ONCE(ndev->mtu) here, but later > re-read ndev->mtu > > It seems you need to store the READ_ONCE() in a temporary variable, > > unsigned int mtu = READ_ONCE(ndev->mtu); > Indeed, thanks. > > + > > + err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, ndev->mtu, > > + MHI_EOT); > > s/ndev->mtu/mtu/ > > > > + if (err) { > > + if (unlikely(err != -ENOMEM)) > > + net_err_ratelimited("%s: Failed to queue RX buf (%d)\n", > > + ndev->name, err); > > + kfree_skb(skb); > > + break; > > + } > > + > > + atomic_inc(&mhi_netdev->stats.rx_queued); > > This is an unbound loop in the kernel ? > > Please add a : > > cond_resched(); > > Before anyone gets hurt. Will do, thanks. > > > > + } while (1); > > + > > + /* If we're still starved of rx buffers, reschedule latter */ > > + if (unlikely(!atomic_read(&mhi_netdev->stats.rx_queued))) > > + schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2); > > +} > > + > > > >