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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 E8996FA372A for ; Wed, 16 Oct 2019 17:37:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B56AF20663 for ; Wed, 16 Oct 2019 17:37:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=verdurent-com.20150623.gappssmtp.com header.i=@verdurent-com.20150623.gappssmtp.com header.b="f+NsON8M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390376AbfJPRhy (ORCPT ); Wed, 16 Oct 2019 13:37:54 -0400 Received: from mail-vk1-f194.google.com ([209.85.221.194]:36874 "EHLO mail-vk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388899AbfJPRhy (ORCPT ); Wed, 16 Oct 2019 13:37:54 -0400 Received: by mail-vk1-f194.google.com with SMTP id v78so5372007vke.4 for ; Wed, 16 Oct 2019 10:37:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=verdurent-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Lw499SE/B/hjFaUHPEW33doDXG49HvU0MA8Y3SKqLDQ=; b=f+NsON8MCU924pXongPNuXmBEB+tRUxv8lgRxVAdhnNLEJVRp7UCCf5eXF8S3+Jrv0 dMJ/A4WL5ekhgXqrwNh3JXbbdm37/j/gxFi9g7iMj4lgZVQ2MlzujxSSg5F0Tjq/3bP4 jo5XAkwASSBxntr4ggp89/QacdqSgXtm3iaDFhjQd2xl12cf0X/naXACfh4suysLM3QR 85E+4SJK685B6JJMmkb6ogPcLCp9rnNvv0eYDnHbKWjRfoI7O2zWDLRDee/w4oAEVtES RuapFXWoZ/y6YOT0yNpmVMb+ala/CytuzD350PcwFmlFdGInByfCdnYVpPUS0waptOtT WeFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Lw499SE/B/hjFaUHPEW33doDXG49HvU0MA8Y3SKqLDQ=; b=fBhHxjDynzJW1+siqTZSZNjtU3zAUz1i+MAwZPIhk/705wHRawffXDDJq4Eidf1+1Y dNAcWNi08ecB4VMpstpny1wcENSzHHOgHkRRvqdmWXS0mPwipBT2k2NhLRzZqMGvqoDb CxmKXVaKROvez+fqJnhS623GJlr3d5nBCa8JQLbeWH8xHacrUFfoaeuQYsfWXMKKI3XW aCm3jk27sn4FMOr8U4Q+KYtwK3K2K+w9RbDBorPLoMas81Lyu5K70SAPPG3uZUf07n3H jBlQ15KTNez71JTpBzKzirpYnbW4nQTYtnYZjr6HkbYl7Hk/IugQODp7bn1N4eRk4oWq qHYg== X-Gm-Message-State: APjAAAVRAp6qUIIA6vl3eD1udZT+hmaG5REjGiY8h93rSURG/1sqLrlq y7mwuPqPe4OK37LXhCJfYGGFlu6rDZ6mjqgeXSqBs+J0TWPS0w== X-Google-Smtp-Source: APXvYqw+6T+5LMBGMuiz84tkGGsDm2TNA6txkwNEVh5y/8wzUeCrXqRK3UwmkJL5VwwCAAsk+CEkMYOUa6VlV/pR2d8= X-Received: by 2002:a1f:2e0a:: with SMTP id u10mr12656927vku.79.1571246166944; Wed, 16 Oct 2019 10:16:06 -0700 (PDT) MIME-Version: 1.0 References: <20191015061349.141448-1-wvw@google.com> In-Reply-To: From: Amit Kucheria Date: Wed, 16 Oct 2019 22:45:55 +0530 Message-ID: Subject: Re: [PATCH] thermal: create softlink by name for thermal_zone and cooling_device To: Wei Wang Cc: wei.vince.wang@gmail.com, Zhang Rui , Eduardo Valentin , Daniel Lezcano , Linux PM list , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Wed, Oct 16, 2019 at 10:20 PM Amit Kucheria wrote: > > On Tue, Oct 15, 2019 at 11:43 AM Wei Wang wrote: > > > > The paths thermal_zone%d and cooling_device%d are not intuitive and the > > numbers are subject to change due to device tree change. This usually > > leads to tree traversal in userspace code. > > The patch creates `tz-by-name' and `cdev-by-name' for thermal zone and > > cooling_device respectively. > > I like this. > > > Signed-off-by: Wei Wang > > --- > > drivers/thermal/thermal_core.c | 23 +++++++++++++++++++++-- > > 1 file changed, 21 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c > > index d4481cc8958f..0ff8fb1d7b0a 100644 > > --- a/drivers/thermal/thermal_core.c > > +++ b/drivers/thermal/thermal_core.c > > @@ -22,6 +22,7 @@ > > #include > > #include > > #include > > +#include > > > > #define CREATE_TRACE_POINTS > > #include > > @@ -46,6 +47,8 @@ static DEFINE_MUTEX(poweroff_lock); > > > > static atomic_t in_suspend; > > static bool power_off_triggered; > > +static struct kobject *cdev_link_kobj; > > +static struct kobject *tz_link_kobj; > > > > static struct thermal_governor *def_governor; > > > > @@ -954,7 +957,7 @@ __thermal_cooling_device_register(struct device_node *np, > > struct thermal_zone_device *pos = NULL; > > int result; > > > > - if (type && strlen(type) >= THERMAL_NAME_LENGTH) > > + if (!type || !type[0] || strlen(type) >= THERMAL_NAME_LENGTH) > > return ERR_PTR(-EINVAL); > > This should be a separate fix, if needed. > > > if (!ops || !ops->get_max_state || !ops->get_cur_state || > > @@ -989,9 +992,15 @@ __thermal_cooling_device_register(struct device_node *np, > > return ERR_PTR(result); > > } > > > > - /* Add 'this' new cdev to the global cdev list */ > > + /* Add 'this' new cdev to the global cdev list and create link*/ > > mutex_lock(&thermal_list_lock); > > list_add(&cdev->node, &thermal_cdev_list); > > + if (!cdev_link_kobj) > > + cdev_link_kobj = kobject_create_and_add("cdev-by-name", > > + cdev->device.kobj.parent); > > + if (!cdev_link_kobj || sysfs_create_link(cdev_link_kobj, > > + &cdev->device.kobj, cdev->type)) > > + dev_err(&cdev->device, "Failed to create cdev-by-name link\n"); > > Any reason not to use the following form instead? It seems easier to read. > > if (!cdev_link_kobj) { > cdev_link_kobj = kobject_create_and_add("cdev-by-name", > cdev->device.kobj.parent); > ret = sysfs_create_link(cdev_link_kobj, > &cdev->device.kobj, cdev->type)) > if (ret) > dev_err(&cdev->device, "Failed to create > cdev-by-name link\n"); > } I can now see why you had to do that - none of the other links would get created after the first one. Perhaps create the directories in the __init functions and only create the links here? > > mutex_unlock(&thermal_list_lock); > > > > /* Update binding information for 'this' new cdev */ > > @@ -1157,6 +1166,8 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev) > > } > > } > > } > > + if (cdev_link_kobj) > > + sysfs_remove_link(cdev_link_kobj, cdev->type); > > > > mutex_unlock(&thermal_list_lock); > > > > @@ -1340,6 +1351,12 @@ thermal_zone_device_register(const char *type, int trips, int mask, > > > > mutex_lock(&thermal_list_lock); > > list_add_tail(&tz->node, &thermal_tz_list); > > + if (!tz_link_kobj) > > + tz_link_kobj = kobject_create_and_add("tz-by-name", > > + tz->device.kobj.parent); > > + if (!tz_link_kobj || sysfs_create_link(tz_link_kobj, > > + &tz->device.kobj, tz->type)) > > + dev_err(&tz->device, "Failed to create tz-by-name link\n"); > > Same as above. > > > mutex_unlock(&thermal_list_lock); > > > > /* Bind cooling devices for this zone */ > > @@ -1411,6 +1428,8 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz) > > } > > } > > } > > + if (tz_link_kobj) > > + sysfs_remove_link(tz_link_kobj, tz->type); > > > > mutex_unlock(&thermal_list_lock); > > > > -- > > 2.23.0.700.g56cf767bdb-goog > >