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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS 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 78BD2C04AAD for ; Wed, 8 May 2019 13:50:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 13E1121530 for ; Wed, 8 May 2019 13:50:39 +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="GgArHWlW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 13E1121530 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 829C66B0003; Wed, 8 May 2019 09:50:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7DA646B0005; Wed, 8 May 2019 09:50:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 67B9C6B0007; Wed, 8 May 2019 09:50:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-ot1-f72.google.com (mail-ot1-f72.google.com [209.85.210.72]) by kanga.kvack.org (Postfix) with ESMTP id 3EC8A6B0003 for ; Wed, 8 May 2019 09:50:39 -0400 (EDT) Received: by mail-ot1-f72.google.com with SMTP id 72so2054486otv.23 for ; Wed, 08 May 2019 06:50:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:references :in-reply-to:from:date:message-id:subject:to:cc; bh=2EurxZMr2RolSsa7vNYJaos3juIlj/g/eKIBE0b5hok=; b=paahf8rwy+srg4WJfGhfYLzVH/c0cB+6A8Lj/shvnWbeHDnQvUVQHFuZKDwtAyxamy L0rAsYeM2FAUXe40qL/mugfUm0xySxlt3JIMIvvvWxfCOt4Ve0+AsuNXH/K+gxhprcOK fXFH5jhnNHEx8KUo1P1obNJy2etWgAhkLGz2Xgz5HP/AvnZ3xLR2vcgBv4iJFEVN7goC KS5UbFw9FVExHwLwsmGDQulWpN92mumAhaEoaL239rxC9zqPnNau/sPKHIZgaYgxtxrd CDnofhl3TMUWPnJIkcmGpFDJRTBgjNF9uRo4d6B2v6wCzFwjj85ptMukp278O6dIhMUY 2ong== X-Gm-Message-State: APjAAAW+q5Eq3v8VxwUynJGAh+Na3C1elDVF3Jcd17qHVPIlcJbzoZu6 1RC9IhBWf3ctQ2KhUwqbzfZ1ko/TXVSXREqHtludnYZsvN0hmyrr4fF3S77Tu25+KmyoUT9RlVv 3hTlus+hZMgSdqq6WUVXcwKr9Eys3xu0VZ7qD1fsItMVbm/ZaqfivFy5W6Jxej/BEmA== X-Received: by 2002:aca:3d57:: with SMTP id k84mr2157307oia.106.1557323438921; Wed, 08 May 2019 06:50:38 -0700 (PDT) X-Received: by 2002:aca:3d57:: with SMTP id k84mr2157269oia.106.1557323438129; Wed, 08 May 2019 06:50:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1557323438; cv=none; d=google.com; s=arc-20160816; b=EjSYa6q4d1NfkeGwjpVYG3xiOH3mxpEP0kREaEG2+t1/opLPncuhfpU+cq6B1WNaCn ACvlpf39ZUtbbXxkhzDaIqU9vOxd78FQ5ZVRRFxU/WSp+par3cu3us1wqxOPLwXB9PxG Q/WqLrJGD0QUKJKhaQOVs0YykRO5gmpAYnVcfmqQcua3pDKTJpjkJYRgwyA9U0YLCw6w l0gSvcTN1bPR7jd7/3YZ6jZ8+KIjcANbxm0SRXNSbfFBEayjINK1pnONz3EAop4Jm58b KGebQbJTwT8CQzqaAHHygej2QtsSqDGIQV2AbCAt74cL49Hva4WZsGTZ1ZVij9gCKBYc rNMg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=2EurxZMr2RolSsa7vNYJaos3juIlj/g/eKIBE0b5hok=; b=yzqSnyaiYJOkYwsUCIa/7+RtRt+7k8vaT3McfDBOFsAWoU99tU0nmAMEHhpXobLDa1 Lyv1pxyk3kePaLRp2T9lV21a7+Fghf8+Q5GFhPisFDd0YHfWtwTd6XL8bBfQlzE3+KWE xNLpuAhnSHK+dVSdHYnwn6fYtPVD93BlmHqfHEzRj+Y7d1exNKwPr5k8mZh1NNcxdc4D xCRBnUp251yoLsI1gbF2jVRC11RGUJqwd81fW6FiRxQ+Q3uhvNhX/t3xoUau64t0/qGC 8eYupEo5XC0jpwv3/rnJ8VDzSJwe4ZLzsavf1k6cCQF6qIuM5tGmbfYMmExsmVYs9dZO zAxw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=GgArHWlW; spf=pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id s84sor7148231oib.9.2019.05.08.06.50.37 for (Google Transport Security); Wed, 08 May 2019 06:50:37 -0700 (PDT) Received-SPF: pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=GgArHWlW; spf=pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com 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=2EurxZMr2RolSsa7vNYJaos3juIlj/g/eKIBE0b5hok=; b=GgArHWlWkQXoHwkDnK52AErLjHNxY5Gtmfi45DghAvzYSBWNm6e7PeK3JgF31tT39u Q8JR+JNhhGsG4Y7l9oZGDgiuq1Vd5RwpB/qtfTMetqQ89+0JLpGSnC6dCfhpwx19hpSY dW71jKTymLLEW0H/kPBh86F7O8Pl6ugXsxDoo7RkHtzfBaDJhKBBOLKKOiQUz6mX4dfy /qJ/gwBQBKlIHCytwcPCDVmTqECvadxzkRYOgECHpEhiJhC26ncnwbpfGzSI5baBNh4g EXfGGgHq+v/FJ3xWAj5JIAmNaj4uBs1RsRNGNVmeAZDVHZ7DoyszSVQnNrDKMABq0UGH +EKw== X-Google-Smtp-Source: APXvYqyeIjtF65mpJyGOqNS4h3BV3LQvlNHfYva0fI5IeZSoAKQb2exqaAUh3L7sY+Pt68OUPCAnfn3ZcLOt3M41mPQ= X-Received: by 2002:aca:4208:: with SMTP id p8mr2432775oia.105.1557323437130; Wed, 08 May 2019 06:50:37 -0700 (PDT) MIME-Version: 1.0 References: <20190507183804.5512-1-david@redhat.com> <20190507183804.5512-8-david@redhat.com> <1d369ae4-7183-b455-646a-65bbbe697281@redhat.com> In-Reply-To: <1d369ae4-7183-b455-646a-65bbbe697281@redhat.com> From: Dan Williams Date: Wed, 8 May 2019 06:50:25 -0700 Message-ID: Subject: Re: [PATCH v2 7/8] mm/memory_hotplug: Make unregister_memory_block_under_nodes() never fail To: David Hildenbrand Cc: Linux MM , Linux Kernel Mailing List , linux-ia64@vger.kernel.org, linuxppc-dev , linux-s390 , Linux-sh , Andrew Morton , Greg Kroah-Hartman , "Rafael J. Wysocki" , Alex Deucher , "David S. Miller" , Mark Brown , Chris Wilson , Oscar Salvador , Jonathan Cameron Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, May 8, 2019 at 12:22 AM David Hildenbrand wrote: > > > >> drivers/base/node.c | 18 +++++------------- > >> include/linux/node.h | 5 ++--- > >> 2 files changed, 7 insertions(+), 16 deletions(-) > >> > >> diff --git a/drivers/base/node.c b/drivers/base/node.c > >> index 04fdfa99b8bc..9be88fd05147 100644 > >> --- a/drivers/base/node.c > >> +++ b/drivers/base/node.c > >> @@ -803,20 +803,14 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg) > >> > >> /* > >> * Unregister memory block device under all nodes that it spans. > >> + * Has to be called with mem_sysfs_mutex held (due to unlinked_nodes). > > > > Given this comment can bitrot relative to the implementation lets > > instead add an explicit: > > > > lockdep_assert_held(&mem_sysfs_mutex); > > That would require to make the mutex non-static. Is that what you > suggest, or any other alternative? If the concern is other code paths taking the lock when they shouldn't then you could make a public "lockdep_assert_mem_sysfs_held()" to do the same, but I otherwise think the benefit of inline lock validation is worth the price of adding a new non-static symbol.