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=-3.7 required=3.0 tests=BAYES_00, 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 77B7DC43461 for ; Sat, 17 Apr 2021 21:19:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4EBE861354 for ; Sat, 17 Apr 2021 21:19:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237132AbhDQVT3 convert rfc822-to-8bit (ORCPT ); Sat, 17 Apr 2021 17:19:29 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:30925 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237090AbhDQVT2 (ORCPT ); Sat, 17 Apr 2021 17:19:28 -0400 Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-261-JBH8CRNiMlWoKO_dEnAufg-1; Sat, 17 Apr 2021 22:18:58 +0100 X-MC-Unique: JBH8CRNiMlWoKO_dEnAufg-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 17 Apr 2021 22:18:57 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.015; Sat, 17 Apr 2021 22:18:57 +0100 From: David Laight To: 'Matthew Wilcox' , "brouer@redhat.com" CC: "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@linaro.org" , "mcroce@linux.microsoft.com" , "grygorii.strashko@ti.com" , "arnd@kernel.org" , "hch@lst.de" , "linux-snps-arc@lists.infradead.org" , "mhocko@kernel.org" , "mgorman@suse.de" Subject: RE: [PATCH 1/2] mm: Fix struct page layout on 32-bit systems Thread-Topic: [PATCH 1/2] mm: Fix struct page layout on 32-bit systems Thread-Index: AQHXMzO/f1yRrc3ugkWz9MvyD1ZvgKq5Nwpg Date: Sat, 17 Apr 2021 21:18:57 +0000 Message-ID: <386d009232dc42bdaf83d4cc36b13864@AcuMS.aculab.com> References: <20210416230724.2519198-1-willy@infradead.org> <20210416230724.2519198-2-willy@infradead.org> <20210417024522.GP2531743@casper.infradead.org> In-Reply-To: <20210417024522.GP2531743@casper.infradead.org> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Matthew Wilcox > Sent: 17 April 2021 03:45 > > Replacement patch to fix compiler warning. ... > static inline dma_addr_t page_pool_get_dma_addr(struct page *page) > { > - return page->dma_addr; > + dma_addr_t ret = page->dma_addr[0]; > + if (sizeof(dma_addr_t) > sizeof(unsigned long)) > + ret |= (dma_addr_t)page->dma_addr[1] << 16 << 16; Ugly as well. Why not just replace the (dma_addr_t) cast with a (u64) one? Looks better than the double shift. Same could be done for the '>> 32'. Is there an upper_32_bits() that could be used?? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)