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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 72AA9C282DE for ; Wed, 5 Jun 2019 08:37:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4CBBF206B8 for ; Wed, 5 Jun 2019 08:37:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726851AbfFEIhQ (ORCPT ); Wed, 5 Jun 2019 04:37:16 -0400 Received: from mailgw02.mediatek.com ([1.203.163.81]:8564 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726777AbfFEIhQ (ORCPT ); Wed, 5 Jun 2019 04:37:16 -0400 X-UUID: a9760f9322f44717a95caaf2b6654d0c-20190605 X-UUID: a9760f9322f44717a95caaf2b6654d0c-20190605 Received: from mtkcas34.mediatek.inc [(172.27.4.253)] by mailgw02.mediatek.com (envelope-from ) (mailgw01.mediatek.com ESMTP with TLS) with ESMTP id 447371291; Wed, 05 Jun 2019 16:37:10 +0800 Received: from MTKCAS36.mediatek.inc (172.27.4.186) by MTKMBS31N2.mediatek.inc (172.27.4.87) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Wed, 5 Jun 2019 16:37:08 +0800 Received: from [10.17.3.153] (172.27.4.253) by MTKCAS36.mediatek.inc (172.27.4.170) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Wed, 5 Jun 2019 16:37:08 +0800 Message-ID: <1559723828.8487.103.camel@mhfsdcap03> Subject: Re: [PATCH] USB: move usb debugfs directory creation to the usb common core From: Chunfeng Yun To: Felipe Balbi CC: Greg Kroah-Hartman , Matthias Brugger , , , , , Date: Wed, 5 Jun 2019 16:37:08 +0800 In-Reply-To: <871s08ebjn.fsf@linux.intel.com> References: <20190604093258.GB30054@kroah.com> <87tvd5illh.fsf@linux.intel.com> <20190604124349.GA10203@kroah.com> <871s08ebjn.fsf@linux.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, 2019-06-05 at 10:28 +0300, Felipe Balbi wrote: > Hi, > > Greg Kroah-Hartman writes: > >> Greg Kroah-Hartman writes: > >> > diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c > >> > index 7fcb9f782931..f3d6b1ab80cb 100644 > >> > --- a/drivers/usb/core/usb.c > >> > +++ b/drivers/usb/core/usb.c > >> > @@ -1185,19 +1185,17 @@ static struct notifier_block usb_bus_nb = { > >> > .notifier_call = usb_bus_notify, > >> > }; > >> > > >> > -struct dentry *usb_debug_root; > >> > -EXPORT_SYMBOL_GPL(usb_debug_root); > >> > +static struct dentry *usb_devices_root; > >> > > >> > static void usb_debugfs_init(void) > >> > { > >> > - usb_debug_root = debugfs_create_dir("usb", NULL); > >> > - debugfs_create_file("devices", 0444, usb_debug_root, NULL, > >> > - &usbfs_devices_fops); > >> > + usb_devices_root = debugfs_create_file("devices", 0444, usb_debug_root, > >> > >> don't we have a race now? Can usbcore ever probe before usb common? > > > > How can that happen if usb_debug_root is in usb common? The module > > loader will not let that happen. Or it shouldn't :) > > argh, indeed. The very fact that usbcore tries to resolve usb_debug_root > already forces a dependency :-p When build as module, usbcore depend on usb-common, but when buildin, usbcore init before usb-common (use module_init) >