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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 B6052C433E0 for ; Mon, 8 Jun 2020 15:17:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88DD02074B for ; Mon, 8 Jun 2020 15:17:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BEEjtcL9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730127AbgFHPRe (ORCPT ); Mon, 8 Jun 2020 11:17:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729843AbgFHPRb (ORCPT ); Mon, 8 Jun 2020 11:17:31 -0400 Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 843B7C08C5C2 for ; Mon, 8 Jun 2020 08:17:31 -0700 (PDT) Received: by mail-pf1-x42d.google.com with SMTP id b5so8674133pfp.9 for ; Mon, 08 Jun 2020 08:17:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=RWmFg/FpOXpC8fC4p5EowACnCJsVRXBo99Iac+1RUe4=; b=BEEjtcL9BiUhCC2pxnlGAkadTKNs4w++y/f3l+KLZu0KfEVRUYhdHhfTSjiwJBuSNF aEbVyF4z44sFB9n5JV8Cl2s7WnDE2WViyJbgP0a0VkWgXG7T4CEbIh1guLuHAJi+fHkD grJvKw1Bbp28FedBNkTUbE/VbdS3nz04+ortAK5BdrR+K+jv/weK5D/LYbuTsHbaR6Ug Sp5lI/Tu6gYx3g2e4DiGKtUCBKE/m09Bs1ED3hwEK5d7rDxitnBfgt0qqlk2C+2NdApu x7yqu2F2CMXYIsCE3HQBCfXO2eYdz+Q2xY18G1vb6Jx8WOOm0T5QBo7O0xLJ1652y9ku eAzg== 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=RWmFg/FpOXpC8fC4p5EowACnCJsVRXBo99Iac+1RUe4=; b=JsClVApG3ez39UwDA9jBpIZ8CuPgke8/GpPt+w97xRNjdk6jXfvCEjDpncLi8aq8kv Teu4xuhlxjS16ghCRRh3g0XtAgerTg+DBiz5SVjfE2iZrBFGIocem/dzVksQIevhtLc4 WTH3cxPxXZm9yQOX30O+lA0pODzEsTRbpZQRCeFhdWAPruAAKIkiTT30cy27raemLb45 U/FtePF72t9Bw4o8s+xfIIvQnRyG6lJIsYZ9sDrgr75Q5coGcDCV4YJjTVRgQ8cGL1eA O8lCEOaKvYoMZIWoHcatbs/JtQVG9EHGEb1KkOatNMxRYYd5L99oeps/PUXEJNBI6uBd ma8A== X-Gm-Message-State: AOAM532Og1zFsn+Ja1QT6G3IkM24uqh9Bf/70o47lEslHtHKqQME4BQM 4nBu4F2rruMkzU95frCIn9U= X-Google-Smtp-Source: ABdhPJwyn3PPSJoUHGmcph7d+thdSZ03s3peWqRUfw2HhvMN43yq/Jf6zUbQlYGJTBjo1wIZbXB4PQ== X-Received: by 2002:a63:4b0a:: with SMTP id y10mr20731564pga.57.1591629450583; Mon, 08 Jun 2020 08:17:30 -0700 (PDT) Received: from localhost ([49.207.54.212]) by smtp.gmail.com with ESMTPSA id h20sm7391252pfo.105.2020.06.08.08.17.29 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Mon, 08 Jun 2020 08:17:29 -0700 (PDT) Date: Mon, 8 Jun 2020 20:47:27 +0530 From: afzal mohammed To: Arnd Bergmann Cc: Russell King , Linux ARM , "linux-kernel@vger.kernel.org" Subject: Re: ARM: vmsplit 4g/4g Message-ID: <20200608151727.GA5017@afzalpc> References: <20200514111755.GA4997@afzalpc> <20200514133545.GA5020@afzalpc> <20200516060624.GA6371@afzalpc> <20200607125932.GA4576@afzalpc> <20200608111834.GB5736@afzalpc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, Jun 08, 2020 at 04:43:57PM +0200, Arnd Bergmann wrote: > There is another difference: get_user_pages_fast() does not return > a vm_area_struct pointer, which is where you would check the access > permissions. I suppose those pointers could not be returned to callers > that don't already hold the mmap_sem. Ok, thanks for the details, i need to familiarize better with mm. Regards afzal