From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id D94C56B0007 for ; Thu, 3 May 2018 02:47:38 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id c4so14564516pfg.22 for ; Wed, 02 May 2018 23:47:38 -0700 (PDT) Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id h12-v6si198750pls.37.2018.05.02.23.47.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 May 2018 23:47:37 -0700 (PDT) Date: Thu, 3 May 2018 07:47:32 +0100 From: James Hogan 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> Sender: owner-linux-mm@kvack.org List-ID: 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 --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--