Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752808AbcDRNLD (ORCPT ); Mon, 18 Apr 2016 09:11:03 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:37147 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752316AbcDRNK7 (ORCPT ); Mon, 18 Apr 2016 09:10:59 -0400 Date: Mon, 18 Apr 2016 06:10:58 -0700 From: Christoph Hellwig To: okaya@codeaurora.org Cc: Christoph Hellwig , linux-rdma@vger.kernel.org, timur@codeaurora.org, cov@codeaurora.org, Yishai Hadas , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V2] net: ethernet: mellanox: correct page conversion Message-ID: <20160418131058.GA25421@infradead.org> References: <1460845412-13120-1-git-send-email-okaya@codeaurora.org> <20160418121247.GA25387@infradead.org> <0c6a430c5f0ec64f51d7c594ef9751dd@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0c6a430c5f0ec64f51d7c594ef9751dd@codeaurora.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 870 Lines: 22 On Mon, Apr 18, 2016 at 09:06:18AM -0400, okaya@codeaurora.org wrote: > On 2016-04-18 08:12, Christoph Hellwig wrote: > >On Sat, Apr 16, 2016 at 06:23:32PM -0400, Sinan Kaya wrote: > >>Current code is assuming that the address returned by dma_alloc_coherent > >>is a logical address. This is not true on ARM/ARM64 systems. > > > >Can you explain what you mean with a 'logical address' and what actual > >issue you're trying to solve? > > Vmap call is failing on arm64 systems because dma alloc api already returns > an address mapped with vmap. Please state your problem clearly. What I'm reverse engineering from your posts is: because dma_alloc_coherent uses vmap-like mappings on arm64 (all, some systems?) a driver using a lot of them might run into limits of the vmap pool size. Is this correct? > > Please see arch/arm64/mm directory. ---end quoted text---