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 598C7C00140 for ; Sun, 21 Aug 2022 19:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231304AbiHUTMl (ORCPT ); Sun, 21 Aug 2022 15:12:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231193AbiHUTMi (ORCPT ); Sun, 21 Aug 2022 15:12:38 -0400 Received: from mail-ed1-x52d.google.com (mail-ed1-x52d.google.com [IPv6:2a00:1450:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4720C1B7B1 for ; Sun, 21 Aug 2022 12:12:37 -0700 (PDT) Received: by mail-ed1-x52d.google.com with SMTP id s11so11369563edd.13 for ; Sun, 21 Aug 2022 12:12:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=jILonV086DNQ+KWlOgi6a3UzHTGVyIQ7N2DF/l9R5Ms=; b=d6as8TiE4LmDOL120eqrxKyMEZMpLMYZKRTGZ9J0ByyZvoY0XLB/GqMnanObaxp8tG Et6snwtFVB3GEt0jNM4JMqVe2BcB8lm4JY2tItXb+W+tLJYgp6qHCj6+POofV6NPgPec I/hoJdgZ2LFstLdE4PZ/cg+weAgbGm09rQFGDhCxCcMNGy+Df7n5hT6ZZ4kPFVjFOaBd +GjwhLKxtkA4vPUPk1V4wYZW1/FGs5c8CBCvMt8Fcl1PYPY1IgPp8E0ZYik/1mjzC5+0 Fz2yAWujFXCSsMs7K9Qm0aOa0gI9+8eu6rJcp6zRcesak1GRhlIXN+HkyEaps/oNhvCN HcYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=jILonV086DNQ+KWlOgi6a3UzHTGVyIQ7N2DF/l9R5Ms=; b=Dgcjnmtim7b1kWtKzVTHQzFOxmpoMMuk0uqF5SCNFhObXVfOut6C9HLsJPAHvLnXzT Xwa5LOznqwhMuE2OD+s6Sl75WMT8gXhTonKu+HhpxgZEo9fQf9qcYj4Kldjyzf7Ty/EN HZ6A2xGgm0x343NpxQW9dblmjKJPc2MFdZu1w9Gu27vSmUApCQ2zaEfxoRAQLFxZxZzR nMEYo79QYAwXPMgIMrWvlzhlcDLtKup7A4KHBw5Bdb8wazLyl9FPOc4aK2oO6JEeiSOk Y1PEEj+aYdbnts8+1lYUR6P4+Sl6Ve4rDz0RPDR1eu5HTOodTDf6fw2hdPn+HmoA4zti Ga3w== X-Gm-Message-State: ACgBeo3YfAhiNKRAsNwDLJmegF+s4ciRdUODVzTgz0jPJNcwLlzQj+L0 XswLT3loUsql6nobzzXqwmA= X-Google-Smtp-Source: AA6agR6jzKOvGqSaReSFOGzi1pxDqEbFCqv6BU5VfB4swj3L7QT90lmf8GbslEdWIeksHK/NQ0XJdg== X-Received: by 2002:a05:6402:2499:b0:440:942a:40c2 with SMTP id q25-20020a056402249900b00440942a40c2mr13743059eda.37.1661109155774; Sun, 21 Aug 2022 12:12:35 -0700 (PDT) Received: from opensuse.localnet (host-87-17-106-94.retail.telecomitalia.it. [87.17.106.94]) by smtp.gmail.com with ESMTPSA id s13-20020a170906a18d00b0072af102e65csm5149520ejy.152.2022.08.21.12.12.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Aug 2022 12:12:33 -0700 (PDT) From: "Fabio M. De Francesco" To: Christoph Hellwig , Sagi Grimberg Cc: Chaitanya Kulkarni , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Chaitanya Kulkarni , Keith Busch , Ira Weiny Subject: Re: [PATCH v2] nvmet-tcp: Don't kmap() pages which can't come from HIGHMEM Date: Sun, 21 Aug 2022 21:12:30 +0200 Message-ID: <8107517.T7Z3S40VBb@opensuse> In-Reply-To: <20220821054602.GA25754@lst.de> References: <20220817184519.25141-1-fmdefrancesco@gmail.com> <20220821054602.GA25754@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On domenica 21 agosto 2022 07:46:02 CEST Christoph Hellwig wrote: > This introduced tons of pointless over 80 character lines, please stick > to a proper coding style. I'm sorry for this mistake. I'll break those long lines in the next version. > Also or in-kernel I/O wouldn't it make more sense to use a BVEC iter > insted of a KVEC if we have the pages anyway? Or does networking not > support them properly? I must admit I knew practically nothing about this code until I met it while doing my long journey towards kmap() and kmap_atomic() removals. I can say the same for regard to the differences between BVEC iter and KVEC iter. Since you are asking this, today I did some research and read code from other drivers/subsystems, despite this particular issue is out of the scope of my patch. I also read an interesting article in LWN: "The iov_iter interface" at https://lwn.net/Articles/625077/ I may very well be wrong, however I think that iov_iter_kvec() is better suited here. @Sagi, anything to add to this discussion? Thanks, Fabio