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=-8.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_MUTT 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 36A17C282DE for ; Wed, 5 Jun 2019 08:52:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 10BDD20866 for ; Wed, 5 Jun 2019 08:52:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559724744; bh=33U2EKfjRS7h+XMGkmD3adAxfr6fGPYO5U7ZjaS/GaY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ko5GsupO/6Dk/hr0Waez5kkghec4q19J9UrlQCZjzbovjR+XZViZjrYa8PMGHyUvL ZuiioykKsbfyU2bQQZDSZo0WW47KoEtlioLEXxgvfA9L01xhHXGJ8qRNViKtE8Rz+s tjRRxUoZ00Q2qh+cJJ7zHC/kfLRMWbnMFLzA9vYs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726743AbfFEIwT (ORCPT ); Wed, 5 Jun 2019 04:52:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:57048 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726690AbfFEIwT (ORCPT ); Wed, 5 Jun 2019 04:52:19 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 01A322075C; Wed, 5 Jun 2019 08:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559724738; bh=33U2EKfjRS7h+XMGkmD3adAxfr6fGPYO5U7ZjaS/GaY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Jg8LNDdI0PoUYPg/zVrHza4ANwwsNV4xpyvG90wnOrXz6LjtnDwRiaa5W+ti7SflB 7ATBvjKJU2WdvbuNwRTWRQPx0hbf1OrcQiHrmNoWTdDl+jVvYwWMzvNGvfBN/4HMx2 44ObQkLWTyjt8JccrcHrk/wdy3CfHRaHp+UMDTTo= Date: Wed, 5 Jun 2019 10:52:16 +0200 From: Greg Kroah-Hartman To: Chunfeng Yun Cc: Felipe Balbi , Matthias Brugger , linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: Re: [PATCH] USB: move usb debugfs directory creation to the usb common core Message-ID: <20190605085216.GB26984@kroah.com> References: <20190604093258.GB30054@kroah.com> <20190604115919.GA24346@kroah.com> <1559721031.8487.99.camel@mhfsdcap03> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1559721031.8487.99.camel@mhfsdcap03> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, Jun 05, 2019 at 03:50:31PM +0800, Chunfeng Yun wrote: > On Tue, 2019-06-04 at 13:59 +0200, Greg Kroah-Hartman wrote: > > On Tue, Jun 04, 2019 at 11:32:58AM +0200, Greg Kroah-Hartman wrote: > > > The USB gadget subsystem wants to use the USB debugfs root directory, so > > > move it to the common "core" USB code so that it is properly initialized > > > and removed as needed. > > > > > > Signed-off-by: Greg Kroah-Hartman > > > > > > --- > > > > > > This should be the "correct" version of this, Chunfeng, can you test > > > this to verify it works for you? > > > > > > > > > diff --git a/drivers/usb/common/common.c b/drivers/usb/common/common.c > > > index 18f5dcf58b0d..3b5e4263ffef 100644 > > > --- a/drivers/usb/common/common.c > > > +++ b/drivers/usb/common/common.c > > > @@ -15,6 +15,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > > > > static const char *const ep_type_names[] = { > > > [USB_ENDPOINT_XFER_CONTROL] = "ctrl", > > > @@ -291,4 +292,21 @@ struct device *usb_of_get_companion_dev(struct device *dev) > > > EXPORT_SYMBOL_GPL(usb_of_get_companion_dev); > > > #endif > > > > > > +struct dentry *usb_debug_root; > > > +EXPORT_SYMBOL_GPL(usb_debug_root); > > > + > > > +static int usb_common_init(void) > > > +{ > > > + usb_debug_root = debugfs_create_dir("usb", NULL); > > > + return 0; > > > +} > > > + > > > +static void usb_common_exit(void) > > > +{ > > > + debugfs_remove_recursive(usb_debug_root); > > > +} > > > + > > > +module_init(usb_common_init); > I tested this patch. > > Here use module_init() indeed have a race as Felipe said before. > usbcore uses subsys_initcall(), and have a higher priority than > module_init(), so when usbcore tries to create "devices" file, > usb_debug_root is not created. Ah, let me fix that, it should have the same init level and I'll ensure it comes first in the linking. > after I replace it by postcore_initcall() (debugfs uses > core_initcall()), test two cases: > > 1. buildin usbcore/udc-core > > "usb" directory is created, and usb/devices file is also created by > usbcore > > 2. build both usbcore and gadget as ko > > usbcore.ko, udc-core.ko and usb-common.ko are created. > > 2.1 > insmod usb-common.ko // "usb" directory is created > insmod usb-core.ko // usb/devices file is created > > 2.2 > rmmod usb-common.ko // failed, usb_common is in use by usb-core > > 2.3 > rmmod usb-core.ko // usb/devices file is destroyed > rmmod usb-common.ko // usb directory is destroyed > > 2.4 > insmod usb-common.ko // "usb" directory is created > insmod udc-core.ko > > 2.5 > rmmod usb-common.ko // failed, usb_common is in use by udc-core > > 2.6 > rmmod udc-core.ko > rmmod usb-common.ko // usb directory is destroyed > > they are all in line with expectations Wonderful! Let me fix up the init level, and the build issue tha kbuild found, and post a v2 patch. thanks, greg k-h