From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 57D08227E95 for ; Mon, 20 Oct 2025 14:56:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760972181; cv=none; b=Y8F84YLnnD7yAIviPSSz7RXc8G0cT+aagVEHip3V5DyyQOGJ1lktyZEVDmTCMQbWoxa5Fr0AtO0ZW4GYj39fgjj5mgJ8H1RjI5xg+FRa4Mzu8XjUO7S1wpZMyHElBtUU+SpCrrWoGTlJpaR0arNaE9D/rAvC15/9PEx87GvNCDo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760972181; c=relaxed/simple; bh=/HR2FTJi1fhmbceyaoHcX88vfCwNJFFtxcpJPIU9AAU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KdtUGkEOylDvYlcbUIKRNZDH/BanbRUfbeCI+bB8D6hso2fycoj8D+hxb0M/KD5ZJV9bhZEHhPZTbaH9Y8UHwafefe0id1dkUFm8IY7rJcqkWLb5CQ0yi6lFz0owN+t8nXxv5ttxiHBRvDueOorjAp3YlXRU3Aa47+3nAcb+1qs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=h1GdVrlv; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="h1GdVrlv" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760972178; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1k4CgXl3sl9wN3j76v6ryt7WSQ6sNGhilXai3IXkOjA=; b=h1GdVrlvbXm4Ksa47MGapoAtlmZZYIQtZuRasgOOpXJjzEiOvebp45fSXYcaNH7WDC1dep MIpZ3GG6twYlcl3rCi8iODYzw3/3wsSsESfsBrjGTzaoA+vCZPhqQ0kgp8iy++2ZuT9CFO Qarqd6kQTMFcEwxuwlsMmLokVPkRjpY= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-408-WNZPkFVIOvSZB0XEu8-79g-1; Mon, 20 Oct 2025 10:56:17 -0400 X-MC-Unique: WNZPkFVIOvSZB0XEu8-79g-1 X-Mimecast-MFC-AGG-ID: WNZPkFVIOvSZB0XEu8-79g_1760972176 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-426ff59a320so6120366f8f.3 for ; Mon, 20 Oct 2025 07:56:17 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760972176; x=1761576976; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=1k4CgXl3sl9wN3j76v6ryt7WSQ6sNGhilXai3IXkOjA=; b=ZomlCwtiKHxMnRdh/WshGvQqiKV/tBlFNIn9uRvYUFrH6sgK8hy0uTjIMVqmHlxrGL JKPzXHPUgkz2lnk90jlKLlWAKh9fGlKFPqoxUYFkwzRNfN7JEFQCt/V7QzbskdWFMae6 AHvgKJF4GX0BPT0UqWABdrCRX4lghBMfGUWhD2EsYcpYd/PxX7FtVzo8LtzJQ8zvCOpq L3Ncv/+r4IhzYQ+mIHOHLXSG963Q4DF2v17P8Cp8DZdDY86wq0od3Okdmzzf1GsnDiUY 5mQIFC8XI8YR8GEjGbSDT/CMNKELU3ExJHzIegI5/EszFsfyyH1veuB31r4g8ptHA0ZI Gwig== X-Forwarded-Encrypted: i=1; AJvYcCULIGfDrcpREthbHPjLss0JPrrs/sspEq0hywqcA7yXxUJjaGDuw0ILRrw9K+nLQYLbBDA+RGj8Di8=@vger.kernel.org X-Gm-Message-State: AOJu0YyROF/vucstva+bvchucMFDoScoKLlEVFX4RP+W1BHEyktlP8cj i2P8LHAYsS47fCD8ltw5jnNDCq10pECtm4JwW1tB1gvr6johFPe3+xw9DPAU3Od4cYitJoKuujW eM+18G9RK34m5/oHt48wfZ+M2z+3T8E9EOopHQMQx3Zm4jquJjnULPu2tQxH2Bw== X-Gm-Gg: ASbGncubsqqlK7SMUGH2tNfbiP1lnSqMSq8pKs1hQbHYhl3/I+vWHbdZafFQOkAqSzf 7XPmhwqyx7iYRPr0KBFZIXfBRfcX0npIZwx9usGsTRz1Y9NoK7MZ911BLwsbmekcU4/+cnCOI1U q0anJjOkBIAJ9w0JgW9Zq9axXSQIEQbS4e086b5uepax4movnsncJPJaE8pjhjvrkV/hFyr5Mfw 1AMd1Iji78j7VDhqNg61OciJrkXPhiHYCl9+3Pdnu383ocrCOJiAKlGxJFJ9GTrYoS92AY74H5h BD2GnvMzPeWIDMOIASyW6+PEleUPwbpRdlgXilA8kFRNNvURQJT4J96R46GWbfIXVA== X-Received: by 2002:a05:6000:4021:b0:426:d836:f323 with SMTP id ffacd0b85a97d-42704d7e928mr9224479f8f.13.1760972175820; Mon, 20 Oct 2025 07:56:15 -0700 (PDT) X-Google-Smtp-Source: AGHT+IG5sg+KduAEaSO0d/WTabEkdjCGGskJwx7DMn5BIab28WZa40Ixe7cQ3ithEZxOA44qPb92Gw== X-Received: by 2002:a05:6000:4021:b0:426:d836:f323 with SMTP id ffacd0b85a97d-42704d7e928mr9224439f8f.13.1760972175185; Mon, 20 Oct 2025 07:56:15 -0700 (PDT) Received: from fedora ([212.133.41.37]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-427f00ba070sm15840369f8f.42.2025.10.20.07.56.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Oct 2025 07:56:14 -0700 (PDT) Date: Mon, 20 Oct 2025 16:56:08 +0200 From: Matias Ezequiel Vara Larsen To: Francesco Valla Cc: Marc Kleine-Budde , Paolo Abeni , Harald Mommer , Mikhail Golubev-Ciuchea , Wolfgang Grandegger , Eric Dumazet , Jakub Kicinski , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Damir Shaikhutdinov , linux-kernel@vger.kernel.org, linux-can@vger.kernel.org, netdev@vger.kernel.org, virtualization@lists.linux.dev, development@redaril.me Subject: Re: [PATCH v5] can: virtio: Initial virtio CAN driver. Message-ID: References: <20240108131039.2234044-1-Mikhail.Golubev-Ciuchea@opensynergy.com> <2243144.yiUUSuA9gR@fedora.fritz.box> <1997333.7Z3S40VBb9@fedora.fritz.box> Precedence: bulk X-Mailing-List: linux-can@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1997333.7Z3S40VBb9@fedora.fritz.box> On Tue, Oct 14, 2025 at 06:01:07PM +0200, Francesco Valla wrote: > On Tuesday, 14 October 2025 at 12:15:12 Matias Ezequiel Vara Larsen wrote: > > On Thu, Sep 11, 2025 at 10:59:40PM +0200, Francesco Valla wrote: > > > Hello Mikhail, Harald, > > > > > > hoping there will be a v6 of this patch soon, a few comments: > > > > > > On Monday, 8 January 2024 at 14:10:35 Mikhail Golubev-Ciuchea wrote: > > > > > > [...] > > > > + > > > > +/* Compare with m_can.c/m_can_echo_tx_event() */ > > > > +static int virtio_can_read_tx_queue(struct virtqueue *vq) > > > > +{ > > > > + struct virtio_can_priv *can_priv = vq->vdev->priv; > > > > + struct net_device *dev = can_priv->dev; > > > > + struct virtio_can_tx *can_tx_msg; > > > > + struct net_device_stats *stats; > > > > + unsigned long flags; > > > > + unsigned int len; > > > > + u8 result; > > > > + > > > > + stats = &dev->stats; > > > > + > > > > + /* Protect list and virtio queue operations */ > > > > + spin_lock_irqsave(&can_priv->tx_lock, flags); > > > > + > > > > + can_tx_msg = virtqueue_get_buf(vq, &len); > > > > + if (!can_tx_msg) { > > > > + spin_unlock_irqrestore(&can_priv->tx_lock, flags); > > > > + return 0; /* No more data */ > > > > + } > > > > + > > > > + if (unlikely(len < sizeof(struct virtio_can_tx_in))) { > > > > + netdev_err(dev, "TX ACK: Device sent no result code\n"); > > > > + result = VIRTIO_CAN_RESULT_NOT_OK; /* Keep things going */ > > > > + } else { > > > > + result = can_tx_msg->tx_in.result; > > > > + } > > > > + > > > > + if (can_priv->can.state < CAN_STATE_BUS_OFF) { > > > > + /* Here also frames with result != VIRTIO_CAN_RESULT_OK are > > > > + * echoed. Intentional to bring a waiting process in an upper > > > > + * layer to an end. > > > > + * TODO: Any better means to indicate a problem here? > > > > + */ > > > > + if (result != VIRTIO_CAN_RESULT_OK) > > > > + netdev_warn(dev, "TX ACK: Result = %u\n", result); > > > > > > Maybe an error frame reporting CAN_ERR_CRTL_UNSPEC would be better? > > > > > I am not sure. In xilinx_can.c, CAN_ERR_CRTL_UNSPEC is indicated during > > a problem in the rx path and this is the tx path. I think the comment > > refers to improving the way the driver informs this error to the user > > but I may be wrong. > > > > Since we have no detail of what went wrong here, I suggested > CAN_ERR_CRTL_UNSPEC as it is "unspecified error", to be coupled with a > controller error with id CAN_ERR_CRTL; however, a different error might be > more appropriate. > > For sure, at least in my experience, having a warn printed to kmsg is *not* > enough, as the application sending the message(s) would not be able to detect > the error. > > > > > For sure, counting the known errors as valid tx_packets and tx_bytes > > > is misleading. > > > > > > > I'll remove the counters below. > > > > We don't really know what's wrong here - the packet might have been sent and > and then not ACK'ed, as well as any other error condition (as it happens in the > reference implementation from the original authors [1]). Echoing the packet > only "to bring a waiting process in an upper layer to an end" and incrementing > counters feels wrong, but maybe someone more expert than me can advise better > here. > > I agree. IIUC, in case there has been a problem during transmission, I should 1) indicate this by injecting a CAN_ERR_CRTL_UNSPEC package with netif_rx() and 2) use can_free_echo_skb() and increment the tx_error stats. Is this correct? Matias