Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934221AbXJQLFS (ORCPT ); Wed, 17 Oct 2007 07:05:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760212AbXJQLE4 (ORCPT ); Wed, 17 Oct 2007 07:04:56 -0400 Received: from brick.kernel.dk ([87.55.233.238]:20570 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759795AbXJQLEy (ORCPT ); Wed, 17 Oct 2007 07:04:54 -0400 Date: Wed, 17 Oct 2007 13:04:26 +0200 From: Jens Axboe To: David Miller Cc: fujita.tomonori@lab.ntt.co.jp, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: [PATCH] SPARC64: fix iommu sg chaining Message-ID: <20071017110426.GV5043@kernel.dk> References: <20071017091629.GK5043@kernel.dk> <20071017.035441.74746708.davem@davemloft.net> <20071017105840.GT5043@kernel.dk> <20071017.040414.55507057.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071017.040414.55507057.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 916 Lines: 31 On Wed, Oct 17 2007, David Miller wrote: > From: Jens Axboe > Date: Wed, 17 Oct 2007 12:58:40 +0200 > > > The problem is that you cannot zero the entire sg entry, because then > > you'd potentially overwrite the chain pointer. > > > > I'd propose just adding a > > > > sg_dma_address(sg) = 0; > > sg_dma_len(sg) = 0; > > > > there for now, or provide an arch_clear_sg_entry() helper if we need > > more killed. > > The "chain pointer" is indicated by an sg->page with the low > bit set, but we're explicitly initializing it here to a > non-chain page pointer value. > > What's the problem? See next mail :-) -- Jens Axboe - 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/