From patchwork Tue Feb 12 07:25:15 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 10807423 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 305A31575 for ; Tue, 12 Feb 2019 07:25:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 150822915C for ; Tue, 12 Feb 2019 07:25:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0966F2A651; Tue, 12 Feb 2019 07:25:45 +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=unavailable 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 AFD5829933 for ; Tue, 12 Feb 2019 07:25:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726026AbfBLHZn (ORCPT ); Tue, 12 Feb 2019 02:25:43 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:57264 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725936AbfBLHZn (ORCPT ); Tue, 12 Feb 2019 02:25:43 -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=+Jj0P3OpYzmdsxWGOg0JUWIfg/9M8oR4H8vvONKpE2Y=; b=e4UQOorgaMeL2hNotWTeulf85d tQ45Lsg+FHMDh7wFbMtX/AxyAZxpibxzmddHm//JUFLpcT80gcCXxxQHD9QjqHmGo2CT74a65LXta stiUjAgkC+0OmklRfZ3+toIUuQc2eErbz0NIrRmdztzn5JTDZkadifFIhmheyVWWqFMgTGiEqmC94 BLOkoCaAypnoqlZCWWAGo0lXl9s/NjfErN7dTKKbr5juutZAIq1JB4akZTqA4W0V4jXf2y83wBR1s JRINJWx1mU1AdXAlmRRsy76KTWXYxHxoUec849yRXTcuQm8JSAfZd0VJaZxQw4TYnU+IDRk7pr8JL 5icTsR5w==; Received: from 089144210182.atnat0019.highway.a1.net ([89.144.210.182] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gtSRh-0002OC-IA; Tue, 12 Feb 2019 07:25:33 +0000 From: Christoph Hellwig To: Ulf Hansson Cc: Russell King , Nicolas Pitre , Aaro Koskinen , Ben Dooks , linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH 01/14] scatterlist: add sg_kmap_atomic / sg_kunmap_atomic helpers Date: Tue, 12 Feb 2019 08:25:15 +0100 Message-Id: <20190212072528.13167-2-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190212072528.13167-1-hch@lst.de> References: <20190212072528.13167-1-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-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This avoids bug prone open coding of the sg offset handling and also helps to document the limitations of mapping scatterlist entries. Signed-off-by: Christoph Hellwig --- include/linux/scatterlist.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index b96f0d0b5b8f..524cd8448a48 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -2,6 +2,7 @@ #ifndef _LINUX_SCATTERLIST_H #define _LINUX_SCATTERLIST_H +#include #include #include #include @@ -239,6 +240,31 @@ static inline void *sg_virt(struct scatterlist *sg) return page_address(sg_page(sg)) + sg->offset; } +/** + * sg_kmap_atomic - map a S/G list entry to a kernel address + * @sg: scatterlist entry + * + * Return a kernel address for scatterlist entry by kmapping it. Note that + * this function must only be called on scatterlist entries that do not span + * multiple pages. + */ +static inline void *sg_kmap_atomic(struct scatterlist *sg) +{ + if (WARN_ON_ONCE(sg->offset + sg->length > PAGE_SIZE)) + return NULL; + return kmap_atomic(sg_page(sg)) + sg->offset; +} + +/** + * sg_kunmap_atomic - unmap a S/G list entry to a kernel address + * @sg: scatterlist entry + * @ptr: address returned from sg_kmap_atomic + */ +static inline void sg_kunmap_atomic(struct scatterlist *sg, void *ptr) +{ + kunmap_atomic(ptr - sg->offset); +} + /** * sg_init_marker - Initialize markers in sg table * @sgl: The SG table