Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752474AbWCQBJS (ORCPT ); Thu, 16 Mar 2006 20:09:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752477AbWCQBJS (ORCPT ); Thu, 16 Mar 2006 20:09:18 -0500 Received: from test-iport-1.cisco.com ([171.71.176.117]:24927 "EHLO test-iport-1.cisco.com") by vger.kernel.org with ESMTP id S1752474AbWCQBJR (ORCPT ); Thu, 16 Mar 2006 20:09:17 -0500 To: Nick Piggin Cc: Hugh Dickins , Andrew Morton , "Bryan O'Sullivan" , torvalds@osdl.org, hch@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 10 of 20] ipath - support for userspace apps using core driver X-Message-Flag: Warning: May contain useful information References: <71644dd19420ddb07a75.1141922823@localhost.localdomain> <1141948516.10693.55.camel@serpentine.pathscale.com> <1141949262.10693.69.camel@serpentine.pathscale.com> <20060309163740.0b589ea4.akpm@osdl.org> <1142470579.6994.78.camel@localhost.localdomain> <1142475069.6994.114.camel@localhost.localdomain> <1142477579.6994.124.camel@localhost.localdomain> <20060315192813.71a5d31a.akpm@osdl.org> <1142485103.25297.13.camel@camp4.serpentine.com> <20060315213813.747b5967.akpm@osdl.org> <4419062C.6000803@yahoo.com.au> <441A04D0.3060201@yahoo.com.au> From: Roland Dreier Date: Thu, 16 Mar 2006 17:09:15 -0800 In-Reply-To: <441A04D0.3060201@yahoo.com.au> (Nick Piggin's message of "Fri, 17 Mar 2006 11:37:36 +1100") Message-ID: User-Agent: Gnus/5.1007 (Gnus v5.10.7) XEmacs/21.4.18 (linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 17 Mar 2006 01:09:15.0921 (UTC) FILETIME=[6903B810:01C6495F] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 752 Lines: 17 Nick> But it doesn't look like dma_alloc_coherent is guaranteed to Nick> return memory allocated from the regular page allocator, nor Nick> even memory backed by a struct page. Nick> For example, I see one that returns kmalloc()ed memory. If Nick> the pages for the slab are already allocated then __GFP_COMP Nick> will not do anything there. i386 looks like it has a path Nick> that uses ioremap... Ugh. So is there a correct way to map DMA-able memory into userspace? - R. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/