Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07EFFC54E94 for ; Thu, 26 Jan 2023 00:28:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229454AbjAZA2c (ORCPT ); Wed, 25 Jan 2023 19:28:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229458AbjAZA22 (ORCPT ); Wed, 25 Jan 2023 19:28:28 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B81F64687 for ; Wed, 25 Jan 2023 16:28:14 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E943F616ED for ; Thu, 26 Jan 2023 00:28:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9EDCC433EF; Thu, 26 Jan 2023 00:28:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1674692893; bh=Rts4+1Au/Ll1O1kl9uisvJrfAICueoMmMPvZ7zzpAqw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=KuBUX56vtogE4UJe6QcxCQYV1fnGIIAVDRHmEfVf7Io28I7Qne+FMKR+WO3/aPVQ9 +q9b0nfdwqAjtDr4j+Krm5O7RMTO6yhEukGdW/S9RprylHXNKdIq2CXUQIL16AJEf+ a+rdH26novPowhDFg08/Fuj5XWuEI0u+LyTNj48k= Date: Wed, 25 Jan 2023 16:28:10 -0800 From: Andrew Morton To: Suren Baghdasaryan Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, hughlynch@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v3 2/7] mm: introduce vma->vm_flags wrapper functions Message-Id: <20230125162810.ec222773d13cd26c55991fde@linux-foundation.org> In-Reply-To: <20230125233554.153109-3-surenb@google.com> References: <20230125233554.153109-1-surenb@google.com> <20230125233554.153109-3-surenb@google.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 25 Jan 2023 15:35:49 -0800 Suren Baghdasaryan wrote: > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -491,7 +491,15 @@ struct vm_area_struct { > * See vmf_insert_mixed_prot() for discussion. > */ > pgprot_t vm_page_prot; > - unsigned long vm_flags; /* Flags, see mm.h. */ > + > + /* > + * Flags, see mm.h. > + * To modify use {init|reset|set|clear|mod}_vm_flags() functions. > + */ > + union { > + const vm_flags_t vm_flags; > + vm_flags_t __private __vm_flags; > + }; Typically when making a change like this we'll rename the affected field/variable/function/etc. This will reliably and deliberately break unconverted usage sites. This const trick will get us partway there, by breaking setters. But renaming it will break both setters and getters.