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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 EA9AEC433B4 for ; Thu, 15 Apr 2021 18:22:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6AB516105A for ; Thu, 15 Apr 2021 18:22:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6AB516105A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BE0A86B0070; Thu, 15 Apr 2021 14:22:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B767F6B0071; Thu, 15 Apr 2021 14:22:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9BE576B0072; Thu, 15 Apr 2021 14:22:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0063.hostedemail.com [216.40.44.63]) by kanga.kvack.org (Postfix) with ESMTP id 7A65C6B0070 for ; Thu, 15 Apr 2021 14:22:48 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3DCC14404 for ; Thu, 15 Apr 2021 18:22:48 +0000 (UTC) X-FDA: 78035422416.12.1B9FBE0 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf11.hostedemail.com (Postfix) with ESMTP id 5DFF42000261 for ; Thu, 15 Apr 2021 18:22:37 +0000 (UTC) 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=gKCpPVH0zLH7350hew5abAqhtVNiLjtRV76fLbYYb+0=; b=wG2nyDBrfmLZ4TcBpx88r9PWVl 3U4kADELcVjuOPtZ5l8fWM5FpiPi0MvBChU6z4pigm+4d3/IyA/rykcPa6Ez2VigbwsC3UPnAkc+W vmN6atSs4SENxN5qvX557Ool3O69b3V6wSZcG/sJdVonl+UIoHK4kJPxespkgvCzKBL4WcPuyLpsq dViYcOw65GEk5Yxkc7RgzTl1+mj9yvOsC/RM+WdC+denGdvUNnPA+IkH0/brZB3SoO7Z69nF0JFbG amnxq8lvQoXIjmGnk8OMhvVLPob0uEI+l0LEm5vy67THKuFe7CM62OBgG/ON01RHKhpOZ7BZZS/fQ ZY8+hw0g==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lX6cl-008vZa-Uh; Thu, 15 Apr 2021 18:22:01 +0000 Date: Thu, 15 Apr 2021 19:21:55 +0100 From: Matthew Wilcox To: Jesper Dangaard Brouer Cc: David Laight , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "netdev@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mips@vger.kernel.org" , Ilias Apalodimas , Matteo Croce , Grygorii Strashko , Arnd Bergmann , Christoph Hellwig Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210415182155.GD2531743@casper.infradead.org> References: <20210410205246.507048-2-willy@infradead.org> <20210411114307.5087f958@carbon> <20210411103318.GC2531743@casper.infradead.org> <20210412011532.GG2531743@casper.infradead.org> <20210414101044.19da09df@carbon> <20210414115052.GS2531743@casper.infradead.org> <20210414211322.3799afd4@carbon> <20210414213556.GY2531743@casper.infradead.org> <20210415200832.32796445@carbon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210415200832.32796445@carbon> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 5DFF42000261 X-Stat-Signature: djoyiujat4hieterytqcudgxg74t77ua Received-SPF: none (infradead.org>: No applicable sender policy available) receiver=imf11; identity=mailfrom; envelope-from=""; helo=casper.infradead.org; client-ip=90.155.50.34 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1618510957-802976 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Apr 15, 2021 at 08:08:32PM +0200, Jesper Dangaard Brouer wrote: > +static inline > +dma_addr_t page_pool_dma_addr_read(dma_addr_t dma_addr) > +{ > + /* Workaround for storing 64-bit DMA-addr on 32-bit machines in struct > + * page. The page->dma_addr share area with page->compound_head which > + * use bit zero to mark compound pages. This is okay, as DMA-addr are > + * aligned pointers which have bit zero cleared. > + * > + * In the 32-bit case, page->compound_head is 32-bit. Thus, when > + * dma_addr_t is 64-bit it will be located in top 32-bit. Solve by > + * swapping dma_addr 32-bit segments. > + */ > +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT #if defined(CONFIG_ARCH_DMA_ADDR_T_64BIT) && defined(__BIG_ENDIAN) otherwise you'll create the problem on ARM that you're avoiding on PPC ... I think you want to delete the word '_read' from this function name because you're using it for both read and write.