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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 57C2CC35242 for ; Tue, 11 Feb 2020 19:22:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2C26D2086A for ; Tue, 11 Feb 2020 19:22:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581448958; bh=6QUFO4XLIl152E/aHV9pWHYp1OSMRQfAtAj8YjYbj2o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=YQa7bP9ymaF+x+1XLD913dHvafy4r5rxcyauQorpmy11DVm7r5D+tmFkh2hglh2u6 uGU1InUa+n1BioV8bO2JF9qfnBifcAsXp94u64WcRzC9x2dZg8MFhp786Btm3oPL35 JtDggGJiu0GIoi6wp6KagZHctNMdQye9OAt/W27Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729800AbgBKTWh (ORCPT ); Tue, 11 Feb 2020 14:22:37 -0500 Received: from mail.kernel.org ([198.145.29.99]:37662 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730822AbgBKTWh (ORCPT ); Tue, 11 Feb 2020 14:22:37 -0500 Received: from localhost (unknown [104.133.9.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B924120842; Tue, 11 Feb 2020 19:22:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581448956; bh=6QUFO4XLIl152E/aHV9pWHYp1OSMRQfAtAj8YjYbj2o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=idbo4s+/FPE3E/07cj+a1jbxOwhs5O3G+6H/GRfnEOt/KiMoy5jI4Eha8wrYRw6qB LCha0a3iz+Xy66b0zWDBmBhFjUs72qIO+SYea/TBEwaJtGbjDrlXpZMNxOu25uSo1+ E+25XjTOGNz82OFPoDm5FG8tdA5ywuxz5uPGa7T8= Date: Tue, 11 Feb 2020 11:22:36 -0800 From: Greg KH To: Manivannan Sadhasivam Cc: arnd@arndb.de, smohanad@codeaurora.org, jhugo@codeaurora.org, kvalo@codeaurora.org, bjorn.andersson@linaro.org, hemantk@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 02/16] bus: mhi: core: Add support for registering MHI controllers Message-ID: <20200211192236.GB1962867@kroah.com> References: <20200131135009.31477-1-manivannan.sadhasivam@linaro.org> <20200131135009.31477-3-manivannan.sadhasivam@linaro.org> <20200206165606.GA3894455@kroah.com> <20200211191147.GB11908@Mani-XPS-13-9360> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200211191147.GB11908@Mani-XPS-13-9360> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed, Feb 12, 2020 at 12:41:47AM +0530, Manivannan Sadhasivam wrote: > Hi Greg, > > On Thu, Feb 06, 2020 at 05:56:06PM +0100, Greg KH wrote: > > On Fri, Jan 31, 2020 at 07:19:55PM +0530, Manivannan Sadhasivam wrote: > > > +static void mhi_release_device(struct device *dev) > > > +{ > > > + struct mhi_device *mhi_dev = to_mhi_device(dev); > > > + > > > + if (mhi_dev->ul_chan) > > > + mhi_dev->ul_chan->mhi_dev = NULL; > > > > That looks really odd. Why didn't you just drop the reference you > > should have grabbed here for this pointer? You did properly increment > > it when you saved it, right? :) > > > > Well, there is no reference count (kref) exist for mhi_dev. Then something is wrong with your model :( You can't save pointers off to things without reference counting, that is going to cause you real problems. See the coding style document for all the details. > And we really needed to NULL the mhi_dev to avoid any dangling > reference to it. Again, that's not how to do this correctly. > The reason for not having kref is that, each mhi_dev will be used by > maximum of 2 channels only. So thought that refcounting is not needed. > Please correct me if I'm wrong. Please read section 11 of Documentation/process/coding-style.rst thanks, greg k-h