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=-10.0 required=3.0 tests=BAYES_00,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 65ACBC433E5 for ; Mon, 13 Jul 2020 15:39:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39D7020771 for ; Mon, 13 Jul 2020 15:39:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="p5NtX2gb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729875AbgGMPj4 (ORCPT ); Mon, 13 Jul 2020 11:39:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729649AbgGMPj4 (ORCPT ); Mon, 13 Jul 2020 11:39:56 -0400 Received: from mail-ed1-x541.google.com (mail-ed1-x541.google.com [IPv6:2a00:1450:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5823C061755 for ; Mon, 13 Jul 2020 08:39:55 -0700 (PDT) Received: by mail-ed1-x541.google.com with SMTP id g20so14102104edm.4 for ; Mon, 13 Jul 2020 08:39:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=du57OarKMFj2//aqQNh8usAhJGOEHYQoIDCsSqzfRrA=; b=p5NtX2gb+X8NBTzJ3q4wi1YSieEG+HNt+0otz/H/s/4MmLGrJII8dW/W0UVEpeW0Hg qC3dEPnVuhhvBwHhOLmT0GIL1CYUYMo9ubUoSer6T64yW74mkvzKKDKlZDVr19K+cYri LtlbMnBKoOcwmDXe/2csa9LQ7/dQV+rttec6lQsYqYKQLaZDSoi1NaLa2MvaowwAoBYv FeI+RRFcbGjItkCjE4SunsxqoBYnRp76pca1wVuHw/7y67Q/sHjhAzl/ezQtIiTEEG4j yQVjwihttrowt+w804UNoet1fmlmsFKNkFYmUigdIXnkpiItEwYkP2N/ahsYzcyDUeNq Dsyg== 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=du57OarKMFj2//aqQNh8usAhJGOEHYQoIDCsSqzfRrA=; b=pvR+FEi+VVtnzao+ZIP9oxpQ2fGS/Lo7/iqqahRniCbAYUsjQNAIj6OG5a8u5Hm2qo LW60SV8f1GVOZPW670PGPFx1nSMtVCZL22D/vFolxcWaiTCuLW8dDmzcV5WYy0xmh9B4 PTauu3Eukdf6SDXzdVmNSaqDOJ48plV2+Fr4avZA+NFx/LN9o2YvXUn+oIrLYrDb4+1B /RVgItyV7MxRzkU6Z5XJpQxL29GVx3r/ukSs/bySX8hcpIDP/5GuFq/4R8JdkCzDIyKY oXE1Wz+LCzPt7QsGZ1Vulniryc/JubTeVq3nuqm4h9I41+Ly5JwQG47J88jvld8+1Rug Qp+Q== X-Gm-Message-State: AOAM530s270uDq62c3X7NR+zit4H5pkwTGQmYgiSw1/cvWFgOS6oukNI 5FpAKFixVmTKUJgmVCirDlhleepYUy5lKG50SHgFPg== X-Google-Smtp-Source: ABdhPJwvCxFFHwbU4mztcnMn5QN22D7JN5cZqYOUrLmDBOAdReDdsMY67wCR/9JL04AtkGrUTxK3CfgbBEbrs6JuO2k= X-Received: by 2002:aa7:c24d:: with SMTP id y13mr95634335edo.123.1594654794604; Mon, 13 Jul 2020 08:39:54 -0700 (PDT) MIME-Version: 1.0 References: <159457116473.754248.7879464730875147365.stgit@dwillia2-desk3.amr.corp.intel.com> <159457125753.754248.6000936585361264069.stgit@dwillia2-desk3.amr.corp.intel.com> <20200712170945.GA194499@kroah.com> In-Reply-To: <20200712170945.GA194499@kroah.com> From: Dan Williams Date: Mon, 13 Jul 2020 08:39:43 -0700 Message-ID: Subject: Re: [PATCH v2 17/22] drivers/base: Make device_find_child_by_name() compatible with sysfs inputs To: Greg Kroah-Hartman Cc: linux-nvdimm , "Rafael J. Wysocki" , Peter Zijlstra , Vishal L Verma , Dave Hansen , Ard Biesheuvel , Linux MM , Linux Kernel Mailing List , Linux ACPI , Christoph Hellwig , Joao Martins Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 12, 2020 at 10:09 AM Greg Kroah-Hartman wrote: > > On Sun, Jul 12, 2020 at 09:27:37AM -0700, Dan Williams wrote: > > Use sysfs_streq() in device_find_child_by_name() to allow it to use a > > sysfs input string that might contain a trailing newline. > > > > The other "device by name" interfaces, > > {bus,driver,class}_find_device_by_name(), already account for sysfs > > strings. > > > > Cc: Greg Kroah-Hartman > > Cc: "Rafael J. Wysocki" > > Signed-off-by: Dan Williams > > --- > > drivers/base/core.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/base/core.c b/drivers/base/core.c > > index 67d39a90b45c..5d31b962c898 100644 > > --- a/drivers/base/core.c > > +++ b/drivers/base/core.c > > @@ -3078,7 +3078,7 @@ struct device *device_find_child_by_name(struct device *parent, > > > > klist_iter_init(&parent->p->klist_children, &i); > > while ((child = next_device(&i))) > > - if (!strcmp(dev_name(child), name) && get_device(child)) > > + if (sysfs_streq(dev_name(child), name) && get_device(child)) > > Who wants to call this function with a name passed from userspace? > > Not objecting to it, just curious... > The series that incorporates this patch adds a partitioning mechanism to "device-dax region" devices with an: "echo 1 > regionX/create" to create a new partition / sub-instance of a region, and... "echo $devname > regionX/delete" to delete. Where $devname is searched in the child devices of regionX to trigger device_del(). This arrangement avoids one of the design mistakes of libnvdimm which uses a sysfs attribute of the device to delete itself. Parent-device triggered deletion rather than self-deletion avoids those locking entanglements.