From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 03 May 2018 08:47:52 +0200 (CEST) Received: from mail.kernel.org ([198.145.29.99]:41400 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23992212AbeECGroSY57k (ORCPT ); Thu, 3 May 2018 08:47:44 +0200 Received: from jamesdev (jahogan.plus.com [212.159.75.221]) (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 2520821716; Thu, 3 May 2018 06:47:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1525330057; bh=atUrz8JUYCggP1NJYmyJMoLiPTm/wANtoMPVwmC4fvE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=K+RUWaOi+hItKxrkImLMwnXzXs765MbU08JTZD2AD4FV/Ow4QNOPoDRbnQi76U73p 4mGC7x+eZSK2oTHu1jyf4wre8uFOgOCsZVWFZ47LvlCVi9Dm7Sw9Is7fHX4lphpLZz l+prII8mUldICU7/XZr8PNi7RvKHySXrfU3SNB74= Date: Thu, 3 May 2018 07:47:32 +0100 From: James Hogan To: Christoph Hellwig Cc: Konrad Rzeszutek Wilk , iommu@lists.linux-foundation.org, sstabellini@kernel.org, x86@kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, linux-mips@linux-mips.org, sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 11/13] mips,unicore32: swiotlb doesn't need sg->dma_length Message-ID: <20180503064731.GA3971@jamesdev> References: <20180425051539.1989-1-hch@lst.de> <20180425051539.1989-12-hch@lst.de> <20180502222017.GC20766@jamesdev> <20180503035643.GA9781@lst.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="CE+1k2dSO48ffgeK" Content-Disposition: inline In-Reply-To: <20180503035643.GA9781@lst.de> User-Agent: Mutt/1.9.5 (2018-04-13) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 63855 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: jhogan@kernel.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips --CE+1k2dSO48ffgeK Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 03, 2018 at 05:56:43AM +0200, Christoph Hellwig wrote: > On Wed, May 02, 2018 at 11:20:18PM +0100, James Hogan wrote: > > On Wed, Apr 25, 2018 at 07:15:37AM +0200, Christoph Hellwig wrote: > > > Only mips and unicore32 select CONFIG_NEED_SG_DMA_LENGTH when building > > > swiotlb. swiotlb itself never merges segements and doesn't accesses = the > > > dma_length field directly, so drop the dependency. > >=20 > > Is that at odds with Documentation/DMA-API-HOWTO.txt, which seems to > > suggest arch ports should enable it for IOMMUs? >=20 > swiotlb isn't really an iommu.. That being said iommus don't have to > merge segments either if they don't want to, and we have various > implementations that don't. The whole dma api documentation needs > a major overhaul, including merging the various files and dropping a lot > of dead wood. It has been on my todo list for a while, with an inner > hope that someone else would do it before me. Okay, for MIPS: Acked-by: James Hogan Cheers James --CE+1k2dSO48ffgeK Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYIAB0WIQS7lRNBWUYtqfDOVL41zuSGKxAj8gUCWuqwggAKCRA1zuSGKxAj 8jJ0AQDBwGZ2k1NphYwyh6OgPS7IN3FDLAFiO2iFddGI2zSf4AEA9hgbj9kgtHKd 8c/TTL4ZMY/xIMHoCb/jXAC1q13gig8= =IGGZ -----END PGP SIGNATURE----- --CE+1k2dSO48ffgeK--