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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 6E3A1C35DFB for ; Tue, 25 Feb 2020 10:05:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A79D21744 for ; Tue, 25 Feb 2020 10:05:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729952AbgBYKFL (ORCPT ); Tue, 25 Feb 2020 05:05:11 -0500 Received: from mx.socionext.com ([202.248.49.38]:34642 "EHLO mx.socionext.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727016AbgBYKFK (ORCPT ); Tue, 25 Feb 2020 05:05:10 -0500 Received: from unknown (HELO kinkan-ex.css.socionext.com) ([172.31.9.52]) by mx.socionext.com with ESMTP; 25 Feb 2020 19:05:08 +0900 Received: from mail.mfilter.local (m-filter-2 [10.213.24.62]) by kinkan-ex.css.socionext.com (Postfix) with ESMTP id 51B8618008B; Tue, 25 Feb 2020 19:05:08 +0900 (JST) Received: from 172.31.9.51 (172.31.9.51) by m-FILTER with ESMTP; Tue, 25 Feb 2020 19:05:08 +0900 Received: from yuzu.css.socionext.com (yuzu [172.31.8.45]) by kinkan.css.socionext.com (Postfix) with ESMTP id C82F81A0006; Tue, 25 Feb 2020 19:05:07 +0900 (JST) Received: from [10.213.132.48] (unknown [10.213.132.48]) by yuzu.css.socionext.com (Postfix) with ESMTP id AFFD212013D; Tue, 25 Feb 2020 19:05:07 +0900 (JST) Date: Tue, 25 Feb 2020 19:05:07 +0900 From: Kunihiko Hayashi To: Lorenzo Pieralisi , Kishon Vijay Abraham I Subject: Re: [PATCH RESEND] PCI: endpoint: Fix clearing start entry in configfs Cc: , In-Reply-To: <20200221141553.GA15440@e121166-lin.cambridge.arm.com> References: <1576844677-24933-1-git-send-email-hayashi.kunihiko@socionext.com> <20200221141553.GA15440@e121166-lin.cambridge.arm.com> Message-Id: <20200225190506.7DFA.4A936039@socionext.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.70 [ja] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Lorenzo, On Fri, 21 Feb 2020 14:15:53 +0000 wrote: > On Fri, Dec 20, 2019 at 09:24:37PM +0900, Kunihiko Hayashi wrote: > > The value of 'start' entry is no change whenever writing 0 to configfs. > > So the endpoint that stopped once can't restart. > > > > The following command lines are an example restarting endpoint and > > reprogramming configurations after receiving bus-reset. > > > > echo 0 > controllers/66000000.pcie-ep/start > > rm controllers/66000000.pcie-ep/func1 > > ln -s functions/pci_epf_test/func1 controllers/66000000.pcie-ep/ > > echo 1 > controllers/66000000.pcie-ep/start > > > > However, the first 'echo' can't set 0 to 'start', so the last 'echo' can't > > restart endpoint. > > I think your description is not correct - pci_epc_group->start is > just used to check if an endpoint has been started or not (in > pci_epc_epf_unlink() and that's a WARN_ON) but nonetheless this > looks like a bug and ought to be fixed. When pci_epc_group->start keeps 1 after starting this controller with 'echo 1 > start', we can never unlink the func1 from the controller because of WARN_ON. I think that unlink/re-link play initialization role of configfs through 'unbind' and 'bind' functions. However, we can't re-initialize configfs. If this is the intended behavior, my patch will make no sense. > I need Kishon's ACK to proceed. I think so, too. Thank you, > > Thanks, > Lorenzo > > > Fixes: d74679911610 ("PCI: endpoint: Introduce configfs entry for configuring EP functions") > > Cc: Kishon Vijay Abraham I > > Signed-off-by: Kunihiko Hayashi > > --- > > drivers/pci/endpoint/pci-ep-cfs.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c > > index d1288a0..4fead88 100644 > > --- a/drivers/pci/endpoint/pci-ep-cfs.c > > +++ b/drivers/pci/endpoint/pci-ep-cfs.c > > @@ -58,6 +58,7 @@ static ssize_t pci_epc_start_store(struct config_item *item, const char *page, > > > > if (!start) { > > pci_epc_stop(epc); > > + epc_group->start = 0; > > return len; > > } > > > > -- > > 2.7.4 > > --- Best Regards, Kunihiko Hayashi