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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 E6DE8C31E57 for ; Mon, 17 Jun 2019 13:30:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C605020657 for ; Mon, 17 Jun 2019 13:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727377AbfFQNav (ORCPT ); Mon, 17 Jun 2019 09:30:51 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:44647 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725884AbfFQNav (ORCPT ); Mon, 17 Jun 2019 09:30:51 -0400 Received: from threadripper.lan ([149.172.19.189]) by mrelayeu.kundenserver.de (mreue011 [212.227.15.129]) with ESMTPA (Nemesis) id 1Mnq8Y-1iQnn21uzS-00pKbB; Mon, 17 Jun 2019 15:29:50 +0200 From: Arnd Bergmann To: Christoph Hellwig , Marek Szyprowski Cc: Arnd Bergmann , Jesper Dangaard Brouer , Konrad Rzeszutek Wilk , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Robin Murphy , Mike Rapoport , Andrew Morton , Joerg Roedel , xen-devel@lists.xenproject.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH] swiotlb: fix phys_addr_t overflow warning Date: Mon, 17 Jun 2019 15:28:43 +0200 Message-Id: <20190617132946.2817440-1-arnd@arndb.de> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:WxAlzhRk05Boo+/YM4l5i3GHyI9GeBc8OiWCfJusR6LAoI1zMkq mI5T09W/WmD7J75VlpcbwtZqQ0SrDUbM08mliK9OyOpw5VGdZN1zx6lKdkmnejKI2IWefXV gD87Cuo+tKgxk+8DVFi5MULUIVmtKYjNbQ/mH9PLbLfMO/vz0NadJP8Sg5EQz6l4Rygh/yT LeEipTLCyl1mG60QYU9LA== X-UI-Out-Filterresults: notjunk:1;V03:K0:pjHS7vU6GCo=:oYrDoKB2+KgIcpoaYs8GlG uTtBiYh+a9NRCMSK/VAmJBtr3OyY50oWkyFrAONPZtPHVNpiF2a8CHfvo5FAn9V1TMPmHj5jF NHxQxqMxS1V9M23uTBejYpfbDSjtIH/c0sAcPnkGEJkybimAEup6/oze7uWb2eQBnfEFQoWUQ aJy4HSSAKT+4gw0ktzsx3iM6TPn57cocJrG/3j5ZCD/oAdErbgrysiAhEeIY9GWvEVkvjDLUI ONy9C26roR2C6uw20//9hHKteelpqgKuxODx/J/UPtPgIMywqCsDLHqOreyPZIamuMa1y+w5G VfTKrnXuklvNm0PX7w7uJIDUmjaHUOra43Y5OxASS35FYFrpJFZvxfUiVc8eRpYhueBJoiqeA aAO7vgmS0K7aJcv4XsT7yAuXgRNjzO7c8G4uCtniGqhvkCj6f0V3UlfvkLvAEw1olB/EoBZGI 3UqpKNY5rjoEdLlVgcSXpS2IAI4cwApvlzIwjAAoBu4rrtqwv/aK0yvzchZRHvCzAFXGe8bRe +bm04PWiu6yyPZ/yOlveC8euUHfYhoJOdzudhIanL205wpbYyqs+QeylkyGFUUOg3X6Qs5qsa RMJUfD0XDSpuNei092sg7J/xfBCHQmIWZmyPvHOtDnOWOGKcu2l7SMGW+i1PFzF9/LL4Vrn18 3KHw4A+YxFrMfGY9xxypp+kyL9UCU3Vi3s/DYWqc7KuDLjYVMLmoUjW3hGoYprONHKuxNyhn/ ltfrC74ikaZMsbUQaH/Ka2jk6kCcG4leKkdP+w== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On architectures that have a larger dma_addr_t than phys_addr_t, the swiotlb_tbl_map_single() function truncates its return code in the failure path, making it impossible to identify the error later, as we compare to the original value: kernel/dma/swiotlb.c:551:9: error: implicit conversion from 'dma_addr_t' (aka 'unsigned long long') to 'phys_addr_t' (aka 'unsigned int') changes value from 18446744073709551615 to 4294967295 [-Werror,-Wconstant-conversion] return DMA_MAPPING_ERROR; Use an explicit typecast here to convert it to the narrower type, and use the same expression in the error handling later. Fixes: b907e20508d0 ("swiotlb: remove SWIOTLB_MAP_ERROR") Signed-off-by: Arnd Bergmann --- I still think that reverting the original commit would have provided clearer semantics for this corner case, but at least this patch restores the correct behavior. --- drivers/xen/swiotlb-xen.c | 2 +- kernel/dma/swiotlb.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index d53f3493a6b9..cfbe46785a3b 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -402,7 +402,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir, attrs); - if (map == DMA_MAPPING_ERROR) + if (map == (phys_addr_t)DMA_MAPPING_ERROR) return DMA_MAPPING_ERROR; dev_addr = xen_phys_to_bus(map); diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index e906ef2e6315..a3be651973ad 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -548,7 +548,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit()) dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n", size, io_tlb_nslabs, tmp_io_tlb_used); - return DMA_MAPPING_ERROR; + return (phys_addr_t)DMA_MAPPING_ERROR; found: io_tlb_used += nslots; spin_unlock_irqrestore(&io_tlb_lock, flags); @@ -666,7 +666,7 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr, /* Oh well, have to allocate and map a bounce buffer. */ *phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start), *phys, size, dir, attrs); - if (*phys == DMA_MAPPING_ERROR) + if (*phys == (phys_addr_t)DMA_MAPPING_ERROR) return false; /* Ensure that the address returned is DMA'ble */ -- 2.20.0