From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCHv2 1/5] mm: add coherence API for DMA to vmalloc/vmap areas Date: Mon, 04 Jan 2010 07:14:21 +1100 Message-ID: <1262549661.2173.262.camel@pasglop> References: <1261603345-2494-1-git-send-email-James.Bottomley@suse.de> <1261603345-2494-2-git-send-email-James.Bottomley@suse.de> <20091224100853.GA3165@console-pimps.org> <20091224123913.GD5335@parisc-linux.org> <1262467678.2173.244.camel@pasglop> <1262469295.2741.30.camel@mulgrave.site> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1262469295.2741.30.camel@mulgrave.site> Sender: linux-parisc-owner@vger.kernel.org To: James Bottomley Cc: Matthew Wilcox , Matt Fleming , linux-arch@vger.kernel.org, linux-parisc@vger.kernel.org, Christoph Hellwig , Russell King , Paul Mundt List-Id: linux-arch.vger.kernel.org On Sat, 2010-01-02 at 15:54 -0600, James Bottomley wrote: > Well, that's the result of the email thread. XFS is poking deeply into > architectural issues by trying to do I/O on a vmap area. I thought the > consensus was that if xfs wants to do that then it takes complete > responsibility for coherence rather than trying to hide it in a block > API. Well, maybe ... Mostly my comment was about the "other" (standard) DMA APIs, ie, the work you do for XFS just reminded me of that issue I've been thinking about :-) Cheers, Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org ([63.228.1.57]:49483 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752505Ab0ACUO6 (ORCPT ); Sun, 3 Jan 2010 15:14:58 -0500 Subject: Re: [PATCHv2 1/5] mm: add coherence API for DMA to vmalloc/vmap areas From: Benjamin Herrenschmidt In-Reply-To: <1262469295.2741.30.camel@mulgrave.site> References: <1261603345-2494-1-git-send-email-James.Bottomley@suse.de> <1261603345-2494-2-git-send-email-James.Bottomley@suse.de> <20091224100853.GA3165@console-pimps.org> <20091224123913.GD5335@parisc-linux.org> <1262467678.2173.244.camel@pasglop> <1262469295.2741.30.camel@mulgrave.site> Content-Type: text/plain; charset="UTF-8" Date: Mon, 04 Jan 2010 07:14:21 +1100 Message-ID: <1262549661.2173.262.camel@pasglop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: James Bottomley Cc: Matthew Wilcox , Matt Fleming , linux-arch@vger.kernel.org, linux-parisc@vger.kernel.org, Christoph Hellwig , Russell King , Paul Mundt Message-ID: <20100103201421.RdIP-LM666XUoovZm68kcDJIe36-bdgpdRcyQdgROX8@z> On Sat, 2010-01-02 at 15:54 -0600, James Bottomley wrote: > Well, that's the result of the email thread. XFS is poking deeply into > architectural issues by trying to do I/O on a vmap area. I thought the > consensus was that if xfs wants to do that then it takes complete > responsibility for coherence rather than trying to hide it in a block > API. Well, maybe ... Mostly my comment was about the "other" (standard) DMA APIs, ie, the work you do for XFS just reminded me of that issue I've been thinking about :-) Cheers, Ben.