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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 027F8C10DCE for ; Fri, 13 Mar 2020 02:58:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC3B9206F1 for ; Fri, 13 Mar 2020 02:58:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584068332; bh=z0VmFDryNsJqsR+Vkt+HiPrOQWgZfMX+En2Wg0OzFic=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=cAqvSDRAROv6NIuVX3iG/GZ3N83uUoQcgr/0wlz0BPsjSgDFHHguESdkWkJev/k5j vm4aqY8FhpjK2nRDc5I9UYYa45RTrV38EADzB5luV58Mmewhqtyc2X7GZ41dtsNu+9 eYG5w94+wT6DQjIl+VTx7h3VrY2wgZcW4nGDnZWQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726437AbgCMC6v (ORCPT ); Thu, 12 Mar 2020 22:58:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:60022 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726254AbgCMC6v (ORCPT ); Thu, 12 Mar 2020 22:58:51 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 9DA68206B1; Fri, 13 Mar 2020 02:58:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584068330; bh=z0VmFDryNsJqsR+Vkt+HiPrOQWgZfMX+En2Wg0OzFic=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=raulPw5jVHpAQ3iFgheChtiTXV22pbjaSTA+as9HwVhsuzaUHREPZkp6gHzdYnWEh gzITLuVICfqdmffpj9iE8j3amyt8PUwf7siEcs0JVeXls5nCx2g6VrsTEYgg/4heMA p9bX2cPx/9oSRKm4O1cyP4NACNpGfWDfgJst+dEc= Date: Thu, 12 Mar 2020 19:58:50 -0700 From: Andrew Morton To: Souptick Joarder Cc: jglisse@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/hmm.c : Remove additional check for lockdep_assert_held() Message-Id: <20200312195850.29693d4e55ec27ae11443c0f@linux-foundation.org> In-Reply-To: <1584065460-22205-1-git-send-email-jrdr.linux@gmail.com> References: <1584065460-22205-1-git-send-email-jrdr.linux@gmail.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 13 Mar 2020 07:41:00 +0530 Souptick Joarder wrote: > walk_page_range() already has a check for lockdep_assert_held(). > So additional check for lockdep_assert_held() can be removed from > hmm_range_fault(). > > ... > > --- a/mm/hmm.c > +++ b/mm/hmm.c > @@ -681,7 +681,6 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags) > struct mm_struct *mm = range->notifier->mm; > int ret; > > - lockdep_assert_held(&mm->mmap_sem); > > do { > /* If range is no longer valid force retry. */ It isn't very obvious that hmm_range_fault() is and will only be called from walk_page_range() (is it?)