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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE05AEB64D8 for ; Wed, 21 Jun 2023 13:29:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232600AbjFUN3n (ORCPT ); Wed, 21 Jun 2023 09:29:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232586AbjFUN3m (ORCPT ); Wed, 21 Jun 2023 09:29:42 -0400 Received: from mail-wm1-x32e.google.com (mail-wm1-x32e.google.com [IPv6:2a00:1450:4864:20::32e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8522819B7 for ; Wed, 21 Jun 2023 06:29:34 -0700 (PDT) Received: by mail-wm1-x32e.google.com with SMTP id 5b1f17b1804b1-3f9b4b286aaso127535e9.0 for ; Wed, 21 Jun 2023 06:29:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1687354172; x=1689946172; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=EdD6cJh6qu5svt4tCCc88YcqEs1pBBrW5+aY8WHVANw=; b=FVWCzeaws/zcBjOjUu1n3j7WTelwG9JXw5CEnSXuVyoExnw46Vm7mXMycj7Ey0QchI UVjgVZ4W3h5G5DyoOoZIhV8s+QLEGIuDiv7FHV5vIOU910wUI0T7BqJIL3hiUULNn3pB VdLBj/gmBNQfPFQVDSrnzVcXK2S0UMtK8OtAgvQT4uoauo/jz+/SpPUkkiLkSsQxZd2z AEO/hNolEPFpBTzv4Bg80pQfyL3BI9NXzGgzGhDMGTnQxEUxqfg/L5oCp96E0x9VwNVo gpzHx1Oy1YyVpGtZNzIKXvRaHqC7XKKGAEWWjdzzHQPIo3iS6lSAwNv8U3KzzfxEcpnE heFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687354172; x=1689946172; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=EdD6cJh6qu5svt4tCCc88YcqEs1pBBrW5+aY8WHVANw=; b=OwMZfKNHi3fccrkxXDeu5zE8mjOk8t2D5LUTls+lOyf0SHSCE7hdAYzcD9MNRLanpT yUJKHIdHhou0TQ+zWSZRHh/1w/1HyYe/4gUmvgC5XiN3SOeQ7t2YIMQpKcLUWwT9pmS3 vU51aklCMkZwLfWJDEcyyN8pRFyB7XEheAndutzr5SFMIzBMRk3kCDArWGH1yUz69USQ cW3QriZTYShJ+3VXeTDTJTtPOMno5IibWUYfw/d3WQ7UZZ5r7r2HumxnjYyH/gVfHluV P0I30nwgzeasd8zRpvRxWksl/IH0DjBCuzT4n+t+08Aqm9h6VeZpWQNosH0jE1zLpFjx fCJw== X-Gm-Message-State: AC+VfDyHLZ6ynDFpBRuMfeelI5Vx061jAsPzAMOQZopC8LVPjDut+ibk nVUhxMJL2RdUUJzjA0VE7L0q7a2iICD5KZ4Hlf09NQ== X-Google-Smtp-Source: ACHHUZ5oAZ9+8akmbC5AZy2U+cfa4H8NZ/OYc/GWPMsKsUpaTNBCrKI6BrBopugvdCFxO09eZzJcDuVKBMM6NPG7gzE= X-Received: by 2002:a05:600c:3ac9:b0:3f7:3e85:36a with SMTP id d9-20020a05600c3ac900b003f73e85036amr1128926wms.7.1687354172487; Wed, 21 Jun 2023 06:29:32 -0700 (PDT) MIME-Version: 1.0 References: <20230615141144.665148-1-usama.anjum@collabora.com> <20230615141144.665148-3-usama.anjum@collabora.com> <1c1beeda-ceed-fdab-bbf5-1881e0a8b102@collabora.com> In-Reply-To: <1c1beeda-ceed-fdab-bbf5-1881e0a8b102@collabora.com> From: =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= Date: Wed, 21 Jun 2023 15:29:20 +0200 Message-ID: Subject: Re: [PATCH v19 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs To: Muhammad Usama Anjum Cc: Andrei Vagin , Peter Xu , David Hildenbrand , Andrew Morton , Danylo Mocherniuk , Paul Gofman , Cyrill Gorcunov , Mike Rapoport , Nadav Amit , Alexander Viro , Shuah Khan , Christian Brauner , Yang Shi , Vlastimil Babka , "Liam R . Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Matthew Wilcox , Pasha Tatashin , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, 21 Jun 2023 at 08:35, Muhammad Usama Anjum wrote: > On 6/20/23 11:03=E2=80=AFPM, Andrei Vagin wrote: > ... > >> +struct pagemap_scan_private { > >> + struct page_region *vec_buf, cur_buf; > >> + unsigned long long vec_buf_len, vec_buf_index, max_pages, found_p= ages, flags; > > > > should it be just unsigned long? > These internal values are storing data coming from user in struct > pm_scan_arg in which all variables are 64 bit(__u64) explicitly. This is > why we have unsigned long long here. It is absolutely necessary. vec_buf_len and vec_buf_index can only have values in 0..512 range. flags has only a few lower bits defined (this is checked on ioctl entry) and max_pages can be limited to ULONG_MAX. Actually putting `if (!max_pages || max_pages > ULONG_MAX) max_pages =3D ULONG_MAX` would avoid having to check !max_pages during the walk. Best Regards Micha=C5=82 Miros=C5=82aw