From patchwork Thu Nov 22 14:02:59 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 10694275 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 924E413BB for ; Thu, 22 Nov 2018 14:06:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 845602C97E for ; Thu, 22 Nov 2018 14:06:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 780372CDA8; Thu, 22 Nov 2018 14:06:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.7 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B1CF22C97E for ; Thu, 22 Nov 2018 14:06:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395332AbeKWAnL (ORCPT ); Thu, 22 Nov 2018 19:43:11 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:55286 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2395350AbeKWAnL (ORCPT ); Thu, 22 Nov 2018 19:43:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=b0mTsSZ7pnWLHYe0tv9bLnm4xmcVv2T1rI2O6B8DMzE=; b=liIeK+xPUei0lEBxStOyanHUYE TaRXiwE03YnksJRiqDK9vKDV0SuL4zjUX6vtvXUyKf2Clftum0N/fnxl/Oe8pOV+Akw9rlRSWvkqV aGExKqG9sfG4gtPUI3AQwCBME9IiGpDRKV8OXZnOGLK4Wv1FogJk5gIf6KvRKBv+y68w2c7duGRuW RDCyJ9OSOUrTIiuD/Ene81oeB8JyQkj3/5ZhOzfm+H+i41NDb8yMqO0uByUhv0zLzfniM4aXrblwG WkBlTS/mukROY3vYG1mu8DnONxaPTdKme6tU17Sr5ceVtJaJRdhp5oeUzyznkpu3l8215voWO/ArI n2K8GzGA==; Received: from clnet-p19-102.ikbnet.co.at ([83.175.77.102] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gPpZt-0007eI-0G; Thu, 22 Nov 2018 14:03:33 +0000 From: Christoph Hellwig To: iommu@lists.linux-foundation.org Cc: Linus Torvalds , Jon Mason , Joerg Roedel , David Woodhouse , Marek Szyprowski , Robin Murphy , x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, xen-devel@lists.xenproject.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 03/24] dma-mapping: provide a generic DMA_MAPPING_ERROR Date: Thu, 22 Nov 2018 15:02:59 +0100 Message-Id: <20181122140320.24080-4-hch@lst.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181122140320.24080-1-hch@lst.de> References: <20181122140320.24080-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Error handling of the dma_map_single and dma_map_page APIs is a little problematic at the moment, in that we use different encodings in the returned dma_addr_t to indicate an error. That means we require an additional indirect call to figure out if a dma mapping call returned an error, and a lot of boilerplate code to implement these semantics. Instead return the maximum addressable value as the error. As long as we don't allow mapping single-byte ranges with single-byte alignment this value can never be a valid return. Additionaly if drivers do not check the return value from the dma_map* routines this values means they will generally not be pointed to actual memory. Once the default value is added here we can start removing the various mapping_error methods and just rely on this generic check. Signed-off-by: Christoph Hellwig --- include/linux/dma-mapping.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 15bd41447025..c323c539b7cb 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -133,6 +133,8 @@ struct dma_map_ops { u64 (*get_required_mask)(struct device *dev); }; +#define DMA_MAPPING_ERROR (~(dma_addr_t)0) + extern const struct dma_map_ops dma_direct_ops; extern const struct dma_map_ops dma_virt_ops; @@ -576,6 +578,10 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr) const struct dma_map_ops *ops = get_dma_ops(dev); debug_dma_mapping_error(dev, dma_addr); + + if (dma_addr == DMA_MAPPING_ERROR) + return 1; + if (ops->mapping_error) return ops->mapping_error(dev, dma_addr); return 0;