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=-5.7 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,URIBL_BLOCKED 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 18185C433FE for ; Fri, 11 Dec 2020 07:46:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B553123E21 for ; Fri, 11 Dec 2020 07:46:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405422AbgLKHpb (ORCPT ); Fri, 11 Dec 2020 02:45:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:43572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388543AbgLKHpO (ORCPT ); Fri, 11 Dec 2020 02:45:14 -0500 Date: Fri, 11 Dec 2020 08:44:29 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1607672673; bh=PZae96WnzP1vFvimEKQ4F1bK4K9OLoigPkcKSSQwLH4=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=kq6RNr9KfH8w+TGmzkcsVjLHeySDeronzNAmnz9KZS70WZK4wfwZGOs1JfC61Ad/8 ImdBkVj15V08R3zgPk0LoCpvA5Q3nLMg3/lUMKZ4pnYh7QkhqFvw1nszhqscE8aiyJ gq4VRhmB0iBvuGzk7SF9AdsrNFM8anu9KPmjIOes= From: Greg KH To: Hemant Kumar Cc: manivannan.sadhasivam@linaro.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, jhugo@codeaurora.org, bbhatt@codeaurora.org, loic.poulain@linaro.org, netdev@vger.kernel.org Subject: Re: [PATCH v17 3/3] bus: mhi: Add userspace client interface driver Message-ID: References: <1607670251-31733-1-git-send-email-hemantk@codeaurora.org> <1607670251-31733-4-git-send-email-hemantk@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1607670251-31733-4-git-send-email-hemantk@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Thu, Dec 10, 2020 at 11:04:11PM -0800, Hemant Kumar wrote: > This MHI client driver allows userspace clients to transfer > raw data between MHI device and host using standard file operations. > Driver instantiates UCI device object which is associated to device > file node. UCI device object instantiates UCI channel object when device > file node is opened. UCI channel object is used to manage MHI channels > by calling MHI core APIs for read and write operations. MHI channels > are started as part of device open(). MHI channels remain in start > state until last release() is called on UCI device file node. Device > file node is created with format > > /dev/ > > Currently it supports QMI channel. libqmi is userspace MHI client which > communicates to a QMI service using QMI channel. libqmi is a glib-based > library for talking to WWAN modems and devices which speaks QMI protocol. > For more information about libqmi please refer > https://www.freedesktop.org/wiki/Software/libqmi/ This says _what_ this is doing, but not _why_. Why do you want to circumvent the normal user/kernel apis for this type of device and move the normal network handling logic out to userspace? What does that help with? What does the current in-kernel api lack that this userspace interface is going to solve, and why can't the in-kernel api solve it instead? You are pushing a common user/kernel api out of the kernel here, to become very device-specific, with no apparent justification as to why this is happening. Also, because you are going around the existing network api, I will need the networking maintainers to ack this type of patch. thanks, greg k-h