Received: by 2002:ad5:474a:0:0:0:0:0 with SMTP id i10csp3378467imu; Mon, 14 Jan 2019 01:48:23 -0800 (PST) X-Google-Smtp-Source: ALg8bN7t7NqZvdLgb1Mo3T5E1GtPeV9N++9fiIBgEUQ+jEG3Jz+VB8iaNeS/MD1vZ2w4T57V/sm1 X-Received: by 2002:a65:584e:: with SMTP id s14mr22069356pgr.142.1547459303030; Mon, 14 Jan 2019 01:48:23 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1547459303; cv=none; d=google.com; s=arc-20160816; b=JqU9l0vTck3hpSSj6nEo81bQCWlNQtPKf+KdQfntisV2FHQhYQewXScTRAqBeB7w0U eMWhP92NBIwK8Df0xb3TNpmhIj1SLszA9L0eIWk+dmsMHAFEFD8yeF6SbTW9UsHAkbh1 Vq9NSapk/YSpGgZtplNrJiKKObeSt4jfNQcQuZbfrlzUxcd3kAyuzWNL3CZq3gzEHYfV ihWdcejSFetONs3+uFsddkyPSAHc/QRaof7E4pltAwVciT1yNrOTQCae9D4/z6235BmJ +5V29FqRIA40LiIbNeqO8Rf0BWJXA+eZkSN9ENpo1wpzFhPVknDG933OLA/XJc5pdRLg Prbg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=R884tUKGdPdUb8yAm+qGkTyoW0V/IqneXG0MxVvrETk=; b=bu+xlhsb4iH2Qrx4PLxvHVQp2M9WmO+kpB3hav+kX2m0R8Zen3L/0VRApv/nW8goBo SRrF2yFMlziS8FG99rXpQhg0fcFFvBEFRRrqJLeA98W2ZCWGWA3NDOLU1W+MW0TkM0bx G7/jzWWkrzooVvsmZeY/j7gbRDY5WpPuHJ6/GGBwDLg2Hrl2IUX/RM9A/QuwLcnirkHm tV4GJOPq8Oak95PgiGCc7xKeD/ZoDEKaQCehtMrav2/F+eCV+6hY/ZO9LYcbvDu6LQd7 pdOOFc6oscHaH4L3qbaR+N64AY7X1yeP2REG0n90wdEZ6d36dwiQaPploJSLy4Ul1aRV GAwQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p66si51535591pfp.144.2019.01.14.01.48.07; Mon, 14 Jan 2019 01:48:22 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726641AbfANJqQ (ORCPT + 99 others); Mon, 14 Jan 2019 04:46:16 -0500 Received: from verein.lst.de ([213.95.11.211]:45609 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726525AbfANJqQ (ORCPT ); Mon, 14 Jan 2019 04:46:16 -0500 Received: by newverein.lst.de (Postfix, from userid 2407) id 7B16B67358; Mon, 14 Jan 2019 10:46:14 +0100 (CET) Date: Mon, 14 Jan 2019 10:46:14 +0100 From: Christoph Hellwig To: Shiraz Saleem Cc: Jason Gunthorpe , "linux-rdma@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Christoph Hellwig , Imre Deak , Daniel Vetter , "linux-media@vger.kernel.org" , Yong Zhi , Sakari Ailus , Bingbu Cao , Tian Shu Qiu , Jian Xu Zheng , Sinclair Yeh , Thomas Hellstrom , "dri-devel@lists.freedesktop.org" Subject: Re: [PATCH] lib/scatterlist: Provide a DMA page iterator Message-ID: <20190114094614.GA29604@lst.de> References: <20190104223531.GA1705@ziepe.ca> <20190112182704.GA15320@ssaleem-MOBL4.amr.corp.intel.com> <20190112183752.GC16457@mellanox.com> <20190112190305.GA19436@ssaleem-MOBL4.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190112190305.GA19436@ssaleem-MOBL4.amr.corp.intel.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 12, 2019 at 01:03:05PM -0600, Shiraz Saleem wrote: > Well I was trying convert the RDMA drivers to use your new iterator variant > and saw the need for it in locations where we need virtual address of the pages > contained in the SGEs. As far as i can tell that pg_arr[i] value is only ever used for the case where we do an explicit dma coherent allocation, so you should not have to fill it out at all.