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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 63A42C47082 for ; Mon, 7 Jun 2021 18:04:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4AE7860233 for ; Mon, 7 Jun 2021 18:04:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230523AbhFGSGa (ORCPT ); Mon, 7 Jun 2021 14:06:30 -0400 Received: from foss.arm.com ([217.140.110.172]:39498 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230233AbhFGSG3 (ORCPT ); Mon, 7 Jun 2021 14:06:29 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5357B12FC; Mon, 7 Jun 2021 11:04:38 -0700 (PDT) Received: from e120937-lin (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A51313F73D; Mon, 7 Jun 2021 11:04:36 -0700 (PDT) Date: Mon, 7 Jun 2021 19:04:34 +0100 From: Cristian Marussi To: Sudeep Holla Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com, f.fainelli@gmail.com, etienne.carriere@linaro.org, vincent.guittot@linaro.org, souvik.chakravarty@arm.com Subject: Re: [RFC PATCH 02/10] firmware: arm_scmi: Add missing xfer reinit_completion Message-ID: <20210607180434.GC40811@e120937-lin> References: <20210606221232.33768-1-cristian.marussi@arm.com> <20210606221232.33768-3-cristian.marussi@arm.com> <20210607174142.jdirvbasvgl7q4oj@bogus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210607174142.jdirvbasvgl7q4oj@bogus> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, Jun 07, 2021 at 06:42:57PM +0100, Sudeep Holla wrote: > On Sun, Jun 06, 2021 at 11:12:24PM +0100, Cristian Marussi wrote: > > Reusing timed out xfers in a loop can lead to issue if completion was not > > properly reinitialized. > > > > Signed-off-by: Cristian Marussi > > --- > > drivers/firmware/arm_scmi/driver.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c > > index bee33f9c2032..759ae4a23e74 100644 > > --- a/drivers/firmware/arm_scmi/driver.c > > +++ b/drivers/firmware/arm_scmi/driver.c > > @@ -448,6 +448,7 @@ static int do_xfer(const struct scmi_protocol_handle *ph, > > xfer->hdr.poll_completion); > > > > xfer->hdr.status = SCMI_SUCCESS; > > + reinit_completion(&xfer->done); > > > > What could happen after xfer_get_init->scmi_xfer_get->reinit_completion > that it needs to be re-initialised again. I don't see any reason for this ? > If there are, please state them explicitly. If this is needed, I would drop > the one in scmi_xfer_get(). > The reason, like I explained in the other reply in hdr.status, is the possibility of do_xfer loops and being more defensive. I agree that if what I blabbed in the other email is acceptable, I could drop the reinit_completion in xfer_get() and just use it before send_message(). Thanks, Cristian > -- > Regards, > Sudeep