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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 0B948C35249 for ; Tue, 4 Feb 2020 01:37:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C09A120732 for ; Tue, 4 Feb 2020 01:37:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="AqptJuqv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C09A120732 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 699AC6B02D9; Mon, 3 Feb 2020 20:37:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 64C2F6B02DB; Mon, 3 Feb 2020 20:37:50 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 560E86B02DC; Mon, 3 Feb 2020 20:37:50 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0239.hostedemail.com [216.40.44.239]) by kanga.kvack.org (Postfix) with ESMTP id 3D0DE6B02D9 for ; Mon, 3 Feb 2020 20:37:50 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id DD405824805A for ; Tue, 4 Feb 2020 01:37:49 +0000 (UTC) X-FDA: 76450733058.02.girl93_273c718640442 X-HE-Tag: girl93_273c718640442 X-Filterd-Recvd-Size: 4099 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Tue, 4 Feb 2020 01:37:49 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 980C321775; Tue, 4 Feb 2020 01:37:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580780268; bh=1JJBUW9acr4K537A51HZRbIevnTRMWqCsi85NEFmwPk=; h=Date:From:To:Subject:In-Reply-To:From; b=AqptJuqvT7QsZtrPu7KpuK4O9POzerIW9NfLgzlXGGcb+A61W70gC+DeAdxH79i+g W2LTbk+hajUOTiQ2486on5ZfVFskvtAgBnFnA0cAwxR+sVj/Cb3k6jRd2gW+nnparr +LUDQc2xZ5/m7LKMJP2Cn2xLqWGMaQxvVn7BNkfg= Date: Mon, 03 Feb 2020 17:37:48 -0800 From: Andrew Morton To: akpm@linux-foundation.org, hch@lst.de, linux-mm@kvack.org, linux@armlinux.org.uk, mm-commits@vger.kernel.org, robin.murphy@arm.com, stable@vger.kernel.org, torvalds@linux-foundation.org, wens@csie.org Subject: [patch 67/67] ARM: dma-api: fix max_pfn off-by-one error in __dma_supported() Message-ID: <20200204013748.ezp0xXg5F%akpm@linux-foundation.org> In-Reply-To: <20200203173311.6269a8be06a05e5a4aa08a93@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: Chen-Yu Tsai Subject: ARM: dma-api: fix max_pfn off-by-one error in __dma_supported() max_pfn, as set in arch/arm/mm/init.c: static void __init find_limits(unsigned long *min, unsigned long *max_low, unsigned long *max_high) { *max_low = PFN_DOWN(memblock_get_current_limit()); *min = PFN_UP(memblock_start_of_DRAM()); *max_high = PFN_DOWN(memblock_end_of_DRAM()); } with memblock_end_of_DRAM() pointing to the next byte after DRAM. As such, max_pfn points to the PFN after the end of DRAM. Thus when using max_pfn to check DMA masks, we should subtract one when checking DMA ranges against it. Commit 8bf1268f48ad ("ARM: dma-api: fix off-by-one error in __dma_supported()") fixed the same issue, but missed this spot. This issue was found while working on the sun4i-csi v4l2 driver on the Allwinner R40 SoC. On Allwinner SoCs, DRAM is offset at 0x40000000, and we are starting to use of_dma_configure() with the "dma-ranges" property in the device tree to have the DMA API handle the offset. In this particular instance, dma-ranges was set to the same range as the actual available (2 GiB) DRAM. The following error appeared when the driver attempted to allocate a buffer: sun4i-csi 1c09000.csi: Coherent DMA mask 0x7fffffff (pfn 0x40000-0xc0000) covers a smaller range of system memory than the DMA zone pfn 0x0-0xc0001 sun4i-csi 1c09000.csi: dma_alloc_coherent of size 307200 failed Fixing the off-by-one error makes things work. Link: http://lkml.kernel.org/r/20191224030239.5656-1-wens@kernel.org Fixes: 11a5aa32562e ("ARM: dma-mapping: check DMA mask against available memory") Fixes: 9f28cde0bc64 ("ARM: another fix for the DMA mapping checks") Fixes: ab746573c405 ("ARM: dma-mapping: allow larger DMA mask than supported") Signed-off-by: Chen-Yu Tsai Reviewed-by: Christoph Hellwig Cc: Russell King Cc: Robin Murphy Cc: Signed-off-by: Andrew Morton --- arch/arm/mm/dma-mapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm/mm/dma-mapping.c~arm-dma-api-fix-max_pfn-off-by-one-error-in-__dma_supported +++ a/arch/arm/mm/dma-mapping.c @@ -221,7 +221,7 @@ EXPORT_SYMBOL(arm_coherent_dma_ops); static int __dma_supported(struct device *dev, u64 mask, bool warn) { - unsigned long max_dma_pfn = min(max_pfn, arm_dma_pfn_limit); + unsigned long max_dma_pfn = min(max_pfn - 1, arm_dma_pfn_limit); /* * Translate the device's DMA mask to a PFN limit. This _