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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 75BF0C433E4 for ; Mon, 13 Jul 2020 13:08:52 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3F7C420738 for ; Mon, 13 Jul 2020 13:08:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="EpUwJRmL"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="M5uPLARN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F7C420738 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=7dtaq79eDT6+VIlO7ynk20t7oANqxfo925JW16APC44=; b=EpUwJRmLlzY06QDd6fG5glm4Q bIHPgYE1+L2fbphN99sll+io5+FTEN8CsSaHKlae+mX6xCJw+qlKMr0S/hesAv957+wHhN9b2GmsX cyY1cnVfYdPcP/TEdBCBWbZNDmuVOD+cXc5IhjUvfJeDYYHWeH/AthI/7hlLov71TFHB++V9N/Ki9 e7SZjJe7iQ0av+Luppt6s70sHbWsmOIj/csPj0ERBTTssbZHqG3dGFpoHT8WLnhfsWOyNnk9GpJK6 Q5T2bD2rEAMmIgvTpykyrCw5NY5PhuL0omF1HKvBCYr5HkakA2Wwc/Rf9KV63Qe2+SSSAJ2bB2XXo GvoAkFkRg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1juyAQ-00043Y-7f; Mon, 13 Jul 2020 13:06:46 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1juyAO-00042s-28; Mon, 13 Jul 2020 13:06:44 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=OqcpgdOdGZwi6J+uiLg6n6Rw5mDd47NeVWUGd6LWGdM=; b=M5uPLARN24iL+ApD0GZi56Vlc5 Dty5/OdSlJsVN1jTIxk4HQKJcGhGAwSgX07MSHpP47Nv7DlaTsbWyKf3gzYEeCAwF1vbcZkuJfGdc f52z2EO3vdO+OwPRfr2ozmWZc5NJ/ZrbF+jnXj10Jz90RfTaECMWPg8XFOuX/sfllFaQgRiRIDjZS 6V4JbqvNpNzaH7aPXz2UgJ5LeqHuZ+ZvchIw72KSHDzStVqlaaxgK3jACmrFmrwmwjPl4siGjHH9x YCACeU6TrwZh5N6FncIFiQbO6BM62nmCh8pkBhSRaEu64gnTWoMolXtgUIb/7t9isChq1DT29vM1c aLYz6yZw==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1juyAC-0000PB-3U; Mon, 13 Jul 2020 13:06:32 +0000 Date: Mon, 13 Jul 2020 14:06:32 +0100 From: Christoph Hellwig To: Palmer Dabbelt Subject: Re: [PATCH 1/3] lib: Add a generic copy_oldmem_page() Message-ID: <20200713130632.GA29945@infradead.org> References: <20200711035544.2832154-1-palmer@dabbelt.com> <20200711035544.2832154-2-palmer@dabbelt.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200711035544.2832154-2-palmer@dabbelt.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, ben-linux@fluff.org, peterz@infradead.org, catalin.marinas@arm.com, linus.walleij@linaro.org, Palmer Dabbelt , brendanhiggins@google.com, zaslonko@linux.ibm.com, mick@ics.forth.gr, glider@google.com, willy@infradead.org, mchehab+samsung@kernel.org, will@kernel.org, mingo@kernel.org, uwe@kleine-koenig.org, bgolaszewski@baylibre.com, masahiroy@kernel.org, linux@armlinux.org.uk, krzk@kernel.org, rppt@linux.ibm.com, takahiro.akashi@linaro.org, kernel-team@android.com, pmladek@suse.com, elver@google.com, keescook@chromium.org, paulmck@kernel.org, broonie@kernel.org, gregory.0xf0@gmail.com, dan.j.williams@intel.com, akpm@linux-foundation.org, linux-arm-kernel@lists.infradead.org, Nick Desaulniers , davidgow@google.com, rdunlap@infradead.org, matti.vaittinen@fi.rohmeurope.com, linux-kernel@vger.kernel.org, Arnd Bergmann , mhiramat@kernel.org, ardb@kernel.org, davem@davemloft.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jul 10, 2020 at 08:55:42PM -0700, Palmer Dabbelt wrote: > +ssize_t copy_oldmem_page(unsigned long pfn, char *buf, > + size_t csize, unsigned long offset, > + int userbuf) > +{ > + void *vaddr; > + > + if (!csize) > + return 0; > + > + vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB); > + if (!vaddr) > + return -ENOMEM; Doing a memremap for every page is very inefficient. Also I don't see why you'd want to even do that. All memory is in the direct mapping for RISC-V. For other architecture that support highmem kmap_atomic_pfn would do the job, which is what I'd use in a generic version. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel