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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7A9D9C4727D for ; Fri, 2 Oct 2020 12:46:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3BF8220672 for ; Fri, 2 Oct 2020 12:46:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601642781; bh=fa8+43VJW2CwRdhfgbeNrekJyH+rurDoEBlBYSP/trc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=pjoqe15mVEJge4IsYW9MwQyjaOD5nVr7jl0/cW4Q3hQvkjtxN8ZPR44pAaoV5cnUh L3pUUr8wT0NkjnLH/58VFrdRuzcZldoLo6mXVBDidT3kZ3G3xX/iJatVi0XviUfpDa RLVBs6POjd4QDM0+ytE51P8SY7D8zTJ4MpVSX5dA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387896AbgJBMqU (ORCPT ); Fri, 2 Oct 2020 08:46:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:52938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726029AbgJBMqT (ORCPT ); Fri, 2 Oct 2020 08:46:19 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 17FC6206CD; Fri, 2 Oct 2020 12:46:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601642777; bh=fa8+43VJW2CwRdhfgbeNrekJyH+rurDoEBlBYSP/trc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=2VEvdYSLvOPfnBqOn4Q6cikgVNV1LQbv90343MmGSySe7NW8IBMDkVme5w3nwPo7q p4Ki3cwQH32pVivcjB33LzoCCexBqmXNkZpdDpXq/BnW4UHOhdCvGCpzZTa4LA9s+O jCWB41vHzizZAhhZMJPLc3uebduLtGInPTtWceNI= Date: Fri, 2 Oct 2020 14:46:16 +0200 From: Greg Kroah-Hartman To: poeschel@lemonage.de Cc: Thierry Reding , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Lee Jones , "open list:PWM SUBSYSTEM" , open list Subject: Re: [PATCH 1/2] pwm: sysfs: Set class on pwm devices Message-ID: <20201002124616.GB3348424@kroah.com> References: <20201002123048.3073128-1-poeschel@lemonage.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201002123048.3073128-1-poeschel@lemonage.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 02, 2020 at 02:30:47PM +0200, poeschel@lemonage.de wrote: > From: Lars Poeschel > > This adds a class to exported pwm devices. > Exporting a pwm through sysfs did not yield udev events. The > dev_uevent_filter function does filter-out devices without a bus or > class. > This was already addressed in commit > commit 7e5d1fd75c3d ("pwm: Set class for exported channels in sysfs") > but this did cause problems and the commit got reverted with > commit c289d6625237 ("Revert "pwm: Set class for exported channels in > sysfs"") > Problem with the previous approach was, that there is a clash if we have > multiple pwmchips: > echo 0 > pwmchip0/export > echo 0 > pwmchip1/export > would both export /sys/class/pwm/pwm0 . > > Now this patch changes the sysfs interface. We do include the pwmchip > number into the pwm directory that gets exported. > With the example above we get: > /sys/class/pwm/pwm-0-0 > /sys/class/pwm/pwm-1-0 > We maintain ABI backward compatibility through symlinks. > /sys/class/pwm/pwmchip0/pwm0 > /sys/class/pwm/pwmchip1/pwm0 > are now symbolic links to the new names. > > Cc: Greg Kroah-Hartman > Signed-off-by: Lars Poeschel > --- > drivers/pwm/sysfs.c | 57 +++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 47 insertions(+), 10 deletions(-) > > diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c > index 449dbc0f49ed..c708da17a857 100644 > --- a/drivers/pwm/sysfs.c > +++ b/drivers/pwm/sysfs.c > @@ -240,8 +240,10 @@ static void pwm_export_release(struct device *child) > > static int pwm_export_child(struct device *parent, struct pwm_device *pwm) > { > + struct pwm_chip *chip = dev_get_drvdata(parent); > struct pwm_export *export; > char *pwm_prop[2]; > + char *link_name; > int ret; > > if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags)) > @@ -256,25 +258,39 @@ static int pwm_export_child(struct device *parent, struct pwm_device *pwm) > export->pwm = pwm; > mutex_init(&export->lock); > > + export->child.class = parent->class; > export->child.release = pwm_export_release; > export->child.parent = parent; > export->child.devt = MKDEV(0, 0); > export->child.groups = pwm_groups; > - dev_set_name(&export->child, "pwm%u", pwm->hwpwm); > + dev_set_name(&export->child, "pwm-%u-%u", chip->base, pwm->hwpwm); > > ret = device_register(&export->child); > - if (ret) { > - clear_bit(PWMF_EXPORTED, &pwm->flags); > - put_device(&export->child); > - export = NULL; > - return ret; > + if (ret) > + goto error; > + > + link_name = kasprintf(GFP_KERNEL, "pwm%u", pwm->hwpwm); > + if (link_name == NULL) { > + ret = -ENOMEM; > + goto dev_unregister; > } > - pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm); > + > + pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=%s", > + export->child.kobj.name); > pwm_prop[1] = NULL; > kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop); Do you still need to do this by hand? Why can't this uevent field belong to the class and have it create this for you automatically when the device is added? > kfree(pwm_prop[0]); > > - return 0; > + ret = sysfs_create_link(&parent->kobj, &export->child.kobj, link_name); You create the link _after_ you told userspace it was there, you raced and lost :( > + return ret; > + > +dev_unregister: > + device_unregister(&export->child); > +error: > + clear_bit(PWMF_EXPORTED, &pwm->flags); > + put_device(&export->child); > + export = NULL; > + return ret; > } > > static int pwm_unexport_match(struct device *child, void *data) > @@ -286,6 +302,7 @@ static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm) > { > struct device *child; > char *pwm_prop[2]; > + char *link_name; > > if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) > return -ENODEV; > @@ -294,7 +311,11 @@ static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm) > if (!child) > return -ENODEV; > > - pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm); > + link_name = kasprintf(GFP_KERNEL, "pwm%u", pwm->hwpwm); > + if (link_name) > + sysfs_delete_link(&parent->kobj, &child->kobj, link_name); > + > + pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=%s", child->kobj.name); > pwm_prop[1] = NULL; > kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop); Same uevent question here. Otherwise, this looks good, nice work in figuring out the is_visable stuff and everything. thanks, greg k-h