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 787EDC54EED for ; Wed, 25 Jan 2023 23:36:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229479AbjAYXgM (ORCPT ); Wed, 25 Jan 2023 18:36:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235929AbjAYXgE (ORCPT ); Wed, 25 Jan 2023 18:36:04 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78B5C5E51A for ; Wed, 25 Jan 2023 15:36:03 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-482d3bf0266so1661047b3.3 for ; Wed, 25 Jan 2023 15:36:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=ijhDThbayE4MrjmcyJpQB4++KqDnXZSVkoWdTA6boxg=; b=qAP7Xe1jWQ2v1pDyzimk/ucUXt6pJgnQPRMzULtUiXJ7miq94fdzWh3UQtS4ELXLXG xnRyMqJvJr9Qyw4fk8i3KNqyrHI6q9BE51NGUhcMbBkXiFN4EkWsXQg+sNncoZfFgpAd pmakogcOD7fawIoyB40GTMQKoodOtmE61jQOjn9IiPN2QveUdh02XHqNgo44qZ1Swkka UsHWmYnCHoE7T0et5kXrXIFTIL10ukIq3X3ayvz36CK5hAZd9JEO8xbOLC65b5H6U0Ms J3NS+Lumkoi4FpH2j3VjTovOoJdkWi+DW6xdc6JIqkzB0eqSo4KKNBbmC2JFmfQN4m9j cFgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ijhDThbayE4MrjmcyJpQB4++KqDnXZSVkoWdTA6boxg=; b=oisXrJ9nNjN19+rP7oWVX1HxLUSgs5w23497396reNy0mR0rupYD+/G9iB6I2hWCPE 9c9D7qIRQHdigLxlkGxLxrLZryMs2V2T2D1Fuu0eQn0BLbxzLZF3iamIm/LQWvYY9xt8 R4b89bmgCG8dt4+mLXkdLNQ/d6tu6HRIxVo0X9uI8NKh77KJBopiwx8XG75j99pTzKxS sN4MBB9425KotZb+OhthkZzqitcUYMLfhYGeff3QbMM6P/25gjAO8SXtsSNHltzIZIg7 FOOirLqXR7DcBGMN888LNqpLTBWbCyjcIKTt+WsF/CcIKfYraork4nsOcuEeoxLCg4Rg YsUw== X-Gm-Message-State: AFqh2kp3HZUpUW3v5ErZ0OvrGVPSUi65JDRXYzoxIhnpqxSNRPYYGe5J aEMn61JzUfgLWyvbf8a5g1EZK2LOmdg= X-Google-Smtp-Source: AMrXdXuKSNG6CNUWpJ2GxlW/S4CYhyc7M4Q5HmRRIO5iXM40geoKvk7b/ruVHPa4Ev+GXlDquQW3EuW1OFs= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:f7b0:20e8:ce66:f98]) (user=surenb job=sendgmr) by 2002:a0d:ff42:0:b0:4e0:8133:2a5a with SMTP id p63-20020a0dff42000000b004e081332a5amr3780554ywf.187.1674689762692; Wed, 25 Jan 2023 15:36:02 -0800 (PST) Date: Wed, 25 Jan 2023 15:35:49 -0800 In-Reply-To: <20230125233554.153109-1-surenb@google.com> Mime-Version: 1.0 References: <20230125233554.153109-1-surenb@google.com> X-Mailer: git-send-email 2.39.1.456.gfc5497dd1b-goog Message-ID: <20230125233554.153109-3-surenb@google.com> Subject: [PATCH v3 2/7] mm: introduce vma->vm_flags wrapper functions From: Suren Baghdasaryan To: akpm@linux-foundation.org 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, surenb@google.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org vm_flags are among VMA attributes which affect decisions like VMA merging and splitting. Therefore all vm_flags modifications are performed after taking exclusive mmap_lock to prevent vm_flags updates racing with such operations. Introduce modifier functions for vm_flags to be used whenever flags are updated. This way we can better check and control correct locking behavior during these updates. Signed-off-by: Suren Baghdasaryan --- include/linux/mm.h | 37 +++++++++++++++++++++++++++++++++++++ include/linux/mm_types.h | 10 +++++++++- 2 files changed, 46 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index c2f62bdce134..bf16ddd544a5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -627,6 +627,43 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) INIT_LIST_HEAD(&vma->anon_vma_chain); } +/* Use when VMA is not part of the VMA tree and needs no locking */ +static inline void init_vm_flags(struct vm_area_struct *vma, + vm_flags_t flags) +{ + ACCESS_PRIVATE(vma, __vm_flags) = flags; +} + +/* Use when VMA is part of the VMA tree and modifications need coordination */ +static inline void reset_vm_flags(struct vm_area_struct *vma, + vm_flags_t flags) +{ + mmap_assert_write_locked(vma->vm_mm); + init_vm_flags(vma, flags); +} + +static inline void set_vm_flags(struct vm_area_struct *vma, + vm_flags_t flags) +{ + mmap_assert_write_locked(vma->vm_mm); + ACCESS_PRIVATE(vma, __vm_flags) |= flags; +} + +static inline void clear_vm_flags(struct vm_area_struct *vma, + vm_flags_t flags) +{ + mmap_assert_write_locked(vma->vm_mm); + ACCESS_PRIVATE(vma, __vm_flags) &= ~flags; +} + +static inline void mod_vm_flags(struct vm_area_struct *vma, + vm_flags_t set, vm_flags_t clear) +{ + mmap_assert_write_locked(vma->vm_mm); + ACCESS_PRIVATE(vma, __vm_flags) |= set; + ACCESS_PRIVATE(vma, __vm_flags) &= ~clear; +} + static inline void vma_set_anonymous(struct vm_area_struct *vma) { vma->vm_ops = NULL; diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 2d6d790d9bed..bccbd5896850 100644 --- 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; + }; /* * For areas with an address space and backing store, -- 2.39.1