From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 13 Aug 2001 15:43:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 13 Aug 2001 15:42:46 -0400 Received: from pizda.ninka.net ([216.101.162.242]:10624 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id ; Mon, 13 Aug 2001 15:42:40 -0400 Date: Mon, 13 Aug 2001 12:42:26 -0700 (PDT) Message-Id: <20010813.124226.92585606.davem@redhat.com> To: groudier@free.fr Cc: alan@lxorguk.ukuu.org.uk, sandy@storm.ca, linux-kernel@vger.kernel.org Subject: Re: struct page to 36 (or 64) bit bus address? From: "David S. Miller" In-Reply-To: <20010813205023.P806-100000@gerard> In-Reply-To: <20010813.072157.71088670.davem@redhat.com> <20010813205023.P806-100000@gerard> X-Mailer: Mew version 2.0 on Emacs 21.0 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=big5 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by leeloo.zip.com.au id FAA11778 From: Grard Roudier Date: Mon, 13 Aug 2001 21:07:50 +0200 (CEST) That's the major problem if we ever want to preserve some ordering in the queuing of SCSI IOs. When DMA mapping operation fails, you simply "stop queueing". Queue freezes and nothing new is executed. DMA wakeup makes you start where you left off. I cannot see any ordering constraints violated by this as a side effect. It is like a "cork" for running scsi commands in the driver. The purpose of the hypothetical kernel thread is to get out of interrupt context if that is deemed necessary. It may not be. Later, David S. Miller davem@redhat.com :.˛mkabzwmb˛mbz_^nrzh&zzޗ++zfh~iz_j:+v)ߣmSy杶ii