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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 E5463C433B4 for ; Fri, 16 Apr 2021 17:08:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BAC29610CB for ; Fri, 16 Apr 2021 17:08:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239008AbhDPRJF (ORCPT ); Fri, 16 Apr 2021 13:09:05 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:34658 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235730AbhDPRJD (ORCPT ); Fri, 16 Apr 2021 13:09:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618592918; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=04d/YP/XeREquXdVGX4E7+iWkSvKezEziIy7Br93wNo=; b=K3dEhQh2Wh29PqYLBCwhdsu7NynwdPvR7SJaBbE1hOGsB3dIlm98Q8ghap4PhTTf5FaEHG 5kyuxmJgyjSMfl0UtmayrYY7kG8gJEPdVeecp5Ls0qK7AyayxfrZ/yjyahOFeu4Pxl666v kDzxpyq5vOXCMklR/LP8LbSAFZTP9DM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-154-t1CdtVGrNiG8scC-Sd9o6A-1; Fri, 16 Apr 2021 13:08:35 -0400 X-MC-Unique: t1CdtVGrNiG8scC-Sd9o6A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B8AC1874998; Fri, 16 Apr 2021 17:08:33 +0000 (UTC) Received: from carbon (unknown [10.36.110.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0E9675D749; Fri, 16 Apr 2021 17:08:24 +0000 (UTC) Date: Fri, 16 Apr 2021 19:08:23 +0200 From: Jesper Dangaard Brouer To: Matthew Wilcox 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 , brouer@redhat.com Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210416190823.3b3aace0@carbon> In-Reply-To: <20210416152755.GL2531743@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> <20210416152755.GL2531743@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 16 Apr 2021 16:27:55 +0100 Matthew Wilcox wrote: > On Thu, Apr 15, 2021 at 08:08:32PM +0200, Jesper Dangaard Brouer wrote: > > See below patch. Where I swap32 the dma address to satisfy > > page->compound having bit zero cleared. (It is the simplest fix I could > > come up with). > > I think this is slightly simpler, and as a bonus code that assumes the > old layout won't compile. This is clever, I like it! When reading the code one just have to remember 'unsigned long' size difference between 64-bit vs 32-bit. And I assume compiler can optimize the sizeof check out then doable. > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 6613b26a8894..5aacc1c10a45 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -97,10 +97,10 @@ struct page { > }; > struct { /* page_pool used by netstack */ > /** > - * @dma_addr: might require a 64-bit value even on > + * @dma_addr: might require a 64-bit value on > * 32-bit architectures. > */ > - dma_addr_t dma_addr; > + unsigned long dma_addr[2]; > }; > struct { /* slab, slob and slub */ > union { > diff --git a/include/net/page_pool.h b/include/net/page_pool.h > index b5b195305346..db7c7020746a 100644 > --- a/include/net/page_pool.h > +++ b/include/net/page_pool.h > @@ -198,7 +198,17 @@ static inline void page_pool_recycle_direct(struct page_pool *pool, > > 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] << 32; > + return ret; > +} > + > +static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr) > +{ > + page->dma_addr[0] = addr; > + if (sizeof(dma_addr_t) > sizeof(unsigned long)) > + page->dma_addr[1] = addr >> 32; > } > > static inline bool is_page_pool_compiled_in(void) > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > index ad8b0707af04..f014fd8c19a6 100644 > --- a/net/core/page_pool.c > +++ b/net/core/page_pool.c > @@ -174,8 +174,10 @@ static void page_pool_dma_sync_for_device(struct page_pool *pool, > struct page *page, > unsigned int dma_sync_size) > { > + dma_addr_t dma_addr = page_pool_get_dma_addr(page); > + > dma_sync_size = min(dma_sync_size, pool->p.max_len); > - dma_sync_single_range_for_device(pool->p.dev, page->dma_addr, > + dma_sync_single_range_for_device(pool->p.dev, dma_addr, > pool->p.offset, dma_sync_size, > pool->p.dma_dir); > } > @@ -226,7 +228,7 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool, > put_page(page); > return NULL; > } > - page->dma_addr = dma; > + page_pool_set_dma_addr(page, dma); > > if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) > page_pool_dma_sync_for_device(pool, page, pool->p.max_len); > @@ -294,13 +296,13 @@ void page_pool_release_page(struct page_pool *pool, struct page *page) > */ > goto skip_dma_unmap; > > - dma = page->dma_addr; > + dma = page_pool_get_dma_addr(page); > > - /* When page is unmapped, it cannot be returned our pool */ > + /* When page is unmapped, it cannot be returned to our pool */ > dma_unmap_page_attrs(pool->p.dev, dma, > PAGE_SIZE << pool->p.order, pool->p.dma_dir, > DMA_ATTR_SKIP_CPU_SYNC); > - page->dma_addr = 0; > + page_pool_set_dma_addr(page, 0); > skip_dma_unmap: > /* This may be the last page returned, releasing the pool, so > * it is not safe to reference pool afterwards. > -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer 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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 36019C433ED for ; Fri, 16 Apr 2021 17:08:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A496D61073 for ; Fri, 16 Apr 2021 17:08:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A496D61073 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1C0246B0036; Fri, 16 Apr 2021 13:08:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 149386B006C; Fri, 16 Apr 2021 13:08:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F04A76B0070; Fri, 16 Apr 2021 13:08:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0001.hostedemail.com [216.40.44.1]) by kanga.kvack.org (Postfix) with ESMTP id CDC486B0036 for ; Fri, 16 Apr 2021 13:08:40 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 7D6311EF2 for ; Fri, 16 Apr 2021 17:08:40 +0000 (UTC) X-FDA: 78038864400.15.1475776 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf27.hostedemail.com (Postfix) with ESMTP id 410A680192F0 for ; Fri, 16 Apr 2021 17:08:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618592919; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=04d/YP/XeREquXdVGX4E7+iWkSvKezEziIy7Br93wNo=; b=EBTEYHFC05RVzbHV+IM21itH7EZJjPt3eex0ghXI2GKillFEQ0OzninC3yjJk/sTxFKIT6 alcn2OeUR9y9Pb5D0IYp2LiyKPB9W/Ogqs3UY6McONsyWYVwFHnkuWKAl3j25rdX8kRpQR uuw8elh0SnDqUubr439k3eOhxSwYxDw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-154-t1CdtVGrNiG8scC-Sd9o6A-1; Fri, 16 Apr 2021 13:08:35 -0400 X-MC-Unique: t1CdtVGrNiG8scC-Sd9o6A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B8AC1874998; Fri, 16 Apr 2021 17:08:33 +0000 (UTC) Received: from carbon (unknown [10.36.110.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0E9675D749; Fri, 16 Apr 2021 17:08:24 +0000 (UTC) Date: Fri, 16 Apr 2021 19:08:23 +0200 From: Jesper Dangaard Brouer To: Matthew Wilcox 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 , brouer@redhat.com Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210416190823.3b3aace0@carbon> In-Reply-To: <20210416152755.GL2531743@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> <20210416152755.GL2531743@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Stat-Signature: ahngxde5hgtj7kt6y6u9tctf3rnk8bbz X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 410A680192F0 Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf27; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=170.10.133.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1618592907-731151 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 Fri, 16 Apr 2021 16:27:55 +0100 Matthew Wilcox wrote: > On Thu, Apr 15, 2021 at 08:08:32PM +0200, Jesper Dangaard Brouer wrote: > > See below patch. Where I swap32 the dma address to satisfy > > page->compound having bit zero cleared. (It is the simplest fix I could > > come up with). > > I think this is slightly simpler, and as a bonus code that assumes the > old layout won't compile. This is clever, I like it! When reading the code one just have to remember 'unsigned long' size difference between 64-bit vs 32-bit. And I assume compiler can optimize the sizeof check out then doable. > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 6613b26a8894..5aacc1c10a45 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -97,10 +97,10 @@ struct page { > }; > struct { /* page_pool used by netstack */ > /** > - * @dma_addr: might require a 64-bit value even on > + * @dma_addr: might require a 64-bit value on > * 32-bit architectures. > */ > - dma_addr_t dma_addr; > + unsigned long dma_addr[2]; > }; > struct { /* slab, slob and slub */ > union { > diff --git a/include/net/page_pool.h b/include/net/page_pool.h > index b5b195305346..db7c7020746a 100644 > --- a/include/net/page_pool.h > +++ b/include/net/page_pool.h > @@ -198,7 +198,17 @@ static inline void page_pool_recycle_direct(struct page_pool *pool, > > 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] << 32; > + return ret; > +} > + > +static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr) > +{ > + page->dma_addr[0] = addr; > + if (sizeof(dma_addr_t) > sizeof(unsigned long)) > + page->dma_addr[1] = addr >> 32; > } > > static inline bool is_page_pool_compiled_in(void) > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > index ad8b0707af04..f014fd8c19a6 100644 > --- a/net/core/page_pool.c > +++ b/net/core/page_pool.c > @@ -174,8 +174,10 @@ static void page_pool_dma_sync_for_device(struct page_pool *pool, > struct page *page, > unsigned int dma_sync_size) > { > + dma_addr_t dma_addr = page_pool_get_dma_addr(page); > + > dma_sync_size = min(dma_sync_size, pool->p.max_len); > - dma_sync_single_range_for_device(pool->p.dev, page->dma_addr, > + dma_sync_single_range_for_device(pool->p.dev, dma_addr, > pool->p.offset, dma_sync_size, > pool->p.dma_dir); > } > @@ -226,7 +228,7 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool, > put_page(page); > return NULL; > } > - page->dma_addr = dma; > + page_pool_set_dma_addr(page, dma); > > if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) > page_pool_dma_sync_for_device(pool, page, pool->p.max_len); > @@ -294,13 +296,13 @@ void page_pool_release_page(struct page_pool *pool, struct page *page) > */ > goto skip_dma_unmap; > > - dma = page->dma_addr; > + dma = page_pool_get_dma_addr(page); > > - /* When page is unmapped, it cannot be returned our pool */ > + /* When page is unmapped, it cannot be returned to our pool */ > dma_unmap_page_attrs(pool->p.dev, dma, > PAGE_SIZE << pool->p.order, pool->p.dma_dir, > DMA_ATTR_SKIP_CPU_SYNC); > - page->dma_addr = 0; > + page_pool_set_dma_addr(page, 0); > skip_dma_unmap: > /* This may be the last page returned, releasing the pool, so > * it is not safe to reference pool afterwards. > -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer 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=-8.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 D76B4C433B4 for ; Fri, 16 Apr 2021 17:09:20 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 29BF561073 for ; Fri, 16 Apr 2021 17:09:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 29BF561073 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FMN3f1Yb3z3c2s for ; Sat, 17 Apr 2021 03:09:18 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=EBTEYHFC; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=EBTEYHFC; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=redhat.com (client-ip=170.10.133.124; helo=us-smtp-delivery-124.mimecast.com; envelope-from=brouer@redhat.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=EBTEYHFC; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=EBTEYHFC; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FMN370PHcz2xxt for ; Sat, 17 Apr 2021 03:08:49 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618592919; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=04d/YP/XeREquXdVGX4E7+iWkSvKezEziIy7Br93wNo=; b=EBTEYHFC05RVzbHV+IM21itH7EZJjPt3eex0ghXI2GKillFEQ0OzninC3yjJk/sTxFKIT6 alcn2OeUR9y9Pb5D0IYp2LiyKPB9W/Ogqs3UY6McONsyWYVwFHnkuWKAl3j25rdX8kRpQR uuw8elh0SnDqUubr439k3eOhxSwYxDw= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618592919; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=04d/YP/XeREquXdVGX4E7+iWkSvKezEziIy7Br93wNo=; b=EBTEYHFC05RVzbHV+IM21itH7EZJjPt3eex0ghXI2GKillFEQ0OzninC3yjJk/sTxFKIT6 alcn2OeUR9y9Pb5D0IYp2LiyKPB9W/Ogqs3UY6McONsyWYVwFHnkuWKAl3j25rdX8kRpQR uuw8elh0SnDqUubr439k3eOhxSwYxDw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-154-t1CdtVGrNiG8scC-Sd9o6A-1; Fri, 16 Apr 2021 13:08:35 -0400 X-MC-Unique: t1CdtVGrNiG8scC-Sd9o6A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B8AC1874998; Fri, 16 Apr 2021 17:08:33 +0000 (UTC) Received: from carbon (unknown [10.36.110.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0E9675D749; Fri, 16 Apr 2021 17:08:24 +0000 (UTC) Date: Fri, 16 Apr 2021 19:08:23 +0200 From: Jesper Dangaard Brouer To: Matthew Wilcox Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210416190823.3b3aace0@carbon> In-Reply-To: <20210416152755.GL2531743@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> <20210416152755.GL2531743@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Arnd Bergmann , Grygorii Strashko , "netdev@vger.kernel.org" , Ilias Apalodimas , "linux-kernel@vger.kernel.org" , "linux-mips@vger.kernel.org" , "linux-mm@kvack.org" , David Laight , brouer@redhat.com, Matteo Croce , "linuxppc-dev@lists.ozlabs.org" , Christoph Hellwig , "linux-arm-kernel@lists.infradead.org" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, 16 Apr 2021 16:27:55 +0100 Matthew Wilcox wrote: > On Thu, Apr 15, 2021 at 08:08:32PM +0200, Jesper Dangaard Brouer wrote: > > See below patch. Where I swap32 the dma address to satisfy > > page->compound having bit zero cleared. (It is the simplest fix I could > > come up with). > > I think this is slightly simpler, and as a bonus code that assumes the > old layout won't compile. This is clever, I like it! When reading the code one just have to remember 'unsigned long' size difference between 64-bit vs 32-bit. And I assume compiler can optimize the sizeof check out then doable. > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 6613b26a8894..5aacc1c10a45 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -97,10 +97,10 @@ struct page { > }; > struct { /* page_pool used by netstack */ > /** > - * @dma_addr: might require a 64-bit value even on > + * @dma_addr: might require a 64-bit value on > * 32-bit architectures. > */ > - dma_addr_t dma_addr; > + unsigned long dma_addr[2]; > }; > struct { /* slab, slob and slub */ > union { > diff --git a/include/net/page_pool.h b/include/net/page_pool.h > index b5b195305346..db7c7020746a 100644 > --- a/include/net/page_pool.h > +++ b/include/net/page_pool.h > @@ -198,7 +198,17 @@ static inline void page_pool_recycle_direct(struct page_pool *pool, > > 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] << 32; > + return ret; > +} > + > +static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr) > +{ > + page->dma_addr[0] = addr; > + if (sizeof(dma_addr_t) > sizeof(unsigned long)) > + page->dma_addr[1] = addr >> 32; > } > > static inline bool is_page_pool_compiled_in(void) > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > index ad8b0707af04..f014fd8c19a6 100644 > --- a/net/core/page_pool.c > +++ b/net/core/page_pool.c > @@ -174,8 +174,10 @@ static void page_pool_dma_sync_for_device(struct page_pool *pool, > struct page *page, > unsigned int dma_sync_size) > { > + dma_addr_t dma_addr = page_pool_get_dma_addr(page); > + > dma_sync_size = min(dma_sync_size, pool->p.max_len); > - dma_sync_single_range_for_device(pool->p.dev, page->dma_addr, > + dma_sync_single_range_for_device(pool->p.dev, dma_addr, > pool->p.offset, dma_sync_size, > pool->p.dma_dir); > } > @@ -226,7 +228,7 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool, > put_page(page); > return NULL; > } > - page->dma_addr = dma; > + page_pool_set_dma_addr(page, dma); > > if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) > page_pool_dma_sync_for_device(pool, page, pool->p.max_len); > @@ -294,13 +296,13 @@ void page_pool_release_page(struct page_pool *pool, struct page *page) > */ > goto skip_dma_unmap; > > - dma = page->dma_addr; > + dma = page_pool_get_dma_addr(page); > > - /* When page is unmapped, it cannot be returned our pool */ > + /* When page is unmapped, it cannot be returned to our pool */ > dma_unmap_page_attrs(pool->p.dev, dma, > PAGE_SIZE << pool->p.order, pool->p.dma_dir, > DMA_ATTR_SKIP_CPU_SYNC); > - page->dma_addr = 0; > + page_pool_set_dma_addr(page, 0); > skip_dma_unmap: > /* This may be the last page returned, releasing the pool, so > * it is not safe to reference pool afterwards. > -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer 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=-8.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 1218FC43461 for ; Fri, 16 Apr 2021 17:10:57 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 8E169610CB for ; Fri, 16 Apr 2021 17:10:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8E169610CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID: Subject:Cc: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=6S9YsUzEeVmNe8HtbLBdIzdLnec0cMqZcGQofoaBJi0=; b=XLMe7DCvRmR4uhnUBY4cFm28i AGkl9lX2to5sDpdTsNA3e9Jxt2gmMOhqe76iEQTDBdUpW8w0OPhJRvxf9rTm9K8DQ9FQA8haTkl5E vKWec/ZA9rArY+IpiE8Iq9pu2sEY1jJGYd75tfaHSmjpbdHbWpg98mbXmnynT/2DRLFvLViwL9O5W hOUxgNbhzMwvNMlDtKBXL208naoEZtiAbNuezuNSPoN+LGBeLYCvXpU2av95a8MP0E42uqnl6QDmc /FndBkvJo4V7e5mbyiMB8gdclVMEyj79VxkZNg0rkftUOp7AniWL/zw3pbGPag0V06dUvB1hrB5r0 bPbFjGusQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lXRxf-002u0t-1i; Fri, 16 Apr 2021 17:08:55 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lXRxa-002u0V-Je for linux-arm-kernel@desiato.infradead.org; Fri, 16 Apr 2021 17:08:51 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Sender:Reply-To:Content-ID:Content-Description; bh=04d/YP/XeREquXdVGX4E7+iWkSvKezEziIy7Br93wNo=; b=Ex58YS+Ml94zsTw3mcBi8ZHOJy RsNWWwp93lHd4UMO41l3rxoA1IMwta2dvyO9u5yZoxavfzoKbtG4JmdMOqRCV7Hi6EtZFHhueg9Su 7ikCWsFnhbKrZQAhVvFmMOlI1s1r7YO4mO5plR6d0PcFLts/FrzxWhjr94+julmOThksfRdcQzSiv QRuy1JrcLfjdJRleVXbOiG6MrG1/Nn2PPp+VNLlLAv4YC5z+2/G9em3O3D81oWJx81tqVsfo1U7Gy 8+uBINd1enI4HrZEHM7KwY6e7RY39RuzPDLIk9J3WZohgj71JYWFR88e/+P/l0uretGOrJPaxqcnk SbZ0PDWw==; Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lXRxV-009a7G-1O for linux-arm-kernel@lists.infradead.org; Fri, 16 Apr 2021 17:08:49 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618592919; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=04d/YP/XeREquXdVGX4E7+iWkSvKezEziIy7Br93wNo=; b=EBTEYHFC05RVzbHV+IM21itH7EZJjPt3eex0ghXI2GKillFEQ0OzninC3yjJk/sTxFKIT6 alcn2OeUR9y9Pb5D0IYp2LiyKPB9W/Ogqs3UY6McONsyWYVwFHnkuWKAl3j25rdX8kRpQR uuw8elh0SnDqUubr439k3eOhxSwYxDw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-154-t1CdtVGrNiG8scC-Sd9o6A-1; Fri, 16 Apr 2021 13:08:35 -0400 X-MC-Unique: t1CdtVGrNiG8scC-Sd9o6A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B8AC1874998; Fri, 16 Apr 2021 17:08:33 +0000 (UTC) Received: from carbon (unknown [10.36.110.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0E9675D749; Fri, 16 Apr 2021 17:08:24 +0000 (UTC) Date: Fri, 16 Apr 2021 19:08:23 +0200 From: Jesper Dangaard Brouer To: Matthew Wilcox 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 , brouer@redhat.com Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210416190823.3b3aace0@carbon> In-Reply-To: <20210416152755.GL2531743@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> <20210416152755.GL2531743@casper.infradead.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210416_100845_166159_86EBBF49 X-CRM114-Status: GOOD ( 29.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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, 16 Apr 2021 16:27:55 +0100 Matthew Wilcox wrote: > On Thu, Apr 15, 2021 at 08:08:32PM +0200, Jesper Dangaard Brouer wrote: > > See below patch. Where I swap32 the dma address to satisfy > > page->compound having bit zero cleared. (It is the simplest fix I could > > come up with). > > I think this is slightly simpler, and as a bonus code that assumes the > old layout won't compile. This is clever, I like it! When reading the code one just have to remember 'unsigned long' size difference between 64-bit vs 32-bit. And I assume compiler can optimize the sizeof check out then doable. > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 6613b26a8894..5aacc1c10a45 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -97,10 +97,10 @@ struct page { > }; > struct { /* page_pool used by netstack */ > /** > - * @dma_addr: might require a 64-bit value even on > + * @dma_addr: might require a 64-bit value on > * 32-bit architectures. > */ > - dma_addr_t dma_addr; > + unsigned long dma_addr[2]; > }; > struct { /* slab, slob and slub */ > union { > diff --git a/include/net/page_pool.h b/include/net/page_pool.h > index b5b195305346..db7c7020746a 100644 > --- a/include/net/page_pool.h > +++ b/include/net/page_pool.h > @@ -198,7 +198,17 @@ static inline void page_pool_recycle_direct(struct page_pool *pool, > > 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] << 32; > + return ret; > +} > + > +static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr) > +{ > + page->dma_addr[0] = addr; > + if (sizeof(dma_addr_t) > sizeof(unsigned long)) > + page->dma_addr[1] = addr >> 32; > } > > static inline bool is_page_pool_compiled_in(void) > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > index ad8b0707af04..f014fd8c19a6 100644 > --- a/net/core/page_pool.c > +++ b/net/core/page_pool.c > @@ -174,8 +174,10 @@ static void page_pool_dma_sync_for_device(struct page_pool *pool, > struct page *page, > unsigned int dma_sync_size) > { > + dma_addr_t dma_addr = page_pool_get_dma_addr(page); > + > dma_sync_size = min(dma_sync_size, pool->p.max_len); > - dma_sync_single_range_for_device(pool->p.dev, page->dma_addr, > + dma_sync_single_range_for_device(pool->p.dev, dma_addr, > pool->p.offset, dma_sync_size, > pool->p.dma_dir); > } > @@ -226,7 +228,7 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool, > put_page(page); > return NULL; > } > - page->dma_addr = dma; > + page_pool_set_dma_addr(page, dma); > > if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) > page_pool_dma_sync_for_device(pool, page, pool->p.max_len); > @@ -294,13 +296,13 @@ void page_pool_release_page(struct page_pool *pool, struct page *page) > */ > goto skip_dma_unmap; > > - dma = page->dma_addr; > + dma = page_pool_get_dma_addr(page); > > - /* When page is unmapped, it cannot be returned our pool */ > + /* When page is unmapped, it cannot be returned to our pool */ > dma_unmap_page_attrs(pool->p.dev, dma, > PAGE_SIZE << pool->p.order, pool->p.dma_dir, > DMA_ATTR_SKIP_CPU_SYNC); > - page->dma_addr = 0; > + page_pool_set_dma_addr(page, 0); > skip_dma_unmap: > /* This may be the last page returned, releasing the pool, so > * it is not safe to reference pool afterwards. > -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel