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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 8A89EC2D0EC for ; Thu, 26 Mar 2020 17:56:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 641122070A for ; Thu, 26 Mar 2020 17:56:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="dN59iMRi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727832AbgCZR4r (ORCPT ); Thu, 26 Mar 2020 13:56:47 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:43186 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726363AbgCZR4r (ORCPT ); Thu, 26 Mar 2020 13:56:47 -0400 Received: by mail-qt1-f194.google.com with SMTP id a5so6177097qtw.10 for ; Thu, 26 Mar 2020 10:56:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=7EsDrc+uddu8fCsgx5Mn3RBL0Ax2XMgO8dGY0tetl+Y=; b=dN59iMRichhjpk+p6gNGfCh3Bi5b5fdJo6VsVQp+5jIxncTt09nOeGlvC2364R1UQK 28qDEEWtHtLMtsY7Y93uuCwhCsMFEZV8Q9u0MUU3iAo3vwGlKwfSDLcUB52qs4yRathi f9CO+e8/8mB5y2D2IAfLdwNEebeGksyBOiEk7Quhwoxe3UekgeHM2XCeTmCHEGDlXhB1 1Nynj+0GmlvBMCiMrms/ZgfEFlti0bXyE8d9aW/nG1x8JYcAMKbpRQKvyAwByOSrwzmz vXf0fTlaPEAJt/c09cexX/WpT1IXFxdToO1zkaR1Th4f68+xwHvNkGmigYnCNClbCcjn 7isA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=7EsDrc+uddu8fCsgx5Mn3RBL0Ax2XMgO8dGY0tetl+Y=; b=TqfSSiGsFijEALqa5jKi4EbADgtKGEjzHo5YvVzIcpxtRUDwH8d0fMz76suOePwxFa cfJFV67lhW0zSWI+ZIauQoblZ525CjLo0EYgRncBi42UWIaqmyr2j6UYq7DXjMuQYhsH oSNgOKW6mLFsPLBv5+np5sImyPy16g+YQlQMb4tYcXXhnv2YJ2T/uYWXXTxA8uk5uPVD gOe9aI5k5LRPT6bJN4JIgnsm/NeW+qaa5lHq7rEuMj7ypZ4qZMR2zc6hd5261+Zrebvq r8IA+y9ilNgI4gCN/Qiy1bNC19xmiSSKNOD6QNsAokbwTPAm1qVFjCoQCd0PHR62AoWt HIzA== X-Gm-Message-State: ANhLgQ2SrWE+IoMO9vJLzO4daqwOmIi7me0dCU6+p2e/dloaw5KZhEQD XVxjLgW6aeCS5W1K/UDQd52wfQ== X-Google-Smtp-Source: ADFU+vtFO1P1ti9pC4GHPpqv/P5o9gR83oARQuqK/vl3mHn0NLf/EG76XzbmagOVQWV+0D9RO7eeeQ== X-Received: by 2002:ac8:7c92:: with SMTP id y18mr9687720qtv.189.1585245405416; Thu, 26 Mar 2020 10:56:45 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-68-57-212.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.57.212]) by smtp.gmail.com with ESMTPSA id 68sm1880572qkh.75.2020.03.26.10.56.44 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 26 Mar 2020 10:56:44 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1jHWkG-0002Yj-45; Thu, 26 Mar 2020 14:56:44 -0300 Date: Thu, 26 Mar 2020 14:56:44 -0300 From: Jason Gunthorpe To: Michel Lespinasse Cc: Andrew Morton , linux-mm , LKML , Peter Zijlstra , Laurent Dufour , Vlastimil Babka , Matthew Wilcox , Liam Howlett , Jerome Glisse , Davidlohr Bueso , David Rientjes , Hugh Dickins , Ying Han Subject: Re: [PATCH 1/8] mmap locking API: initial implementation as rwsem wrappers Message-ID: <20200326175644.GN20941@ziepe.ca> References: <20200326070236.235835-1-walken@google.com> <20200326070236.235835-2-walken@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200326070236.235835-2-walken@google.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 26, 2020 at 12:02:29AM -0700, Michel Lespinasse wrote: > +static inline bool mmap_is_locked(struct mm_struct *mm) > +{ > + return rwsem_is_locked(&mm->mmap_sem) != 0; > +} I've been wondering if the various VM_BUG(rwsem_is_locked()) would be better as lockdep expressions? Certainly when lockdep is enabled it should be preferred, IMHO. So, I think if inlines are to be introduced this should be something similar to netdev's ASSERT_RTNL which seems to have worked well. Maybe ASSERT_MMAP_SEM_READ/WRITE/HELD() and do the VM_BUG or lockdep_is_held as appropriate? Jason