From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264014AbTKDJFV (ORCPT ); Tue, 4 Nov 2003 04:05:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264015AbTKDJFV (ORCPT ); Tue, 4 Nov 2003 04:05:21 -0500 Received: from ns.suse.de ([195.135.220.2]:31463 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S264014AbTKDJFP (ORCPT ); Tue, 4 Nov 2003 04:05:15 -0500 Date: Tue, 4 Nov 2003 10:03:53 +0100 From: Jens Axboe To: Herbert Xu Cc: Linux Kernel Mailing List Subject: Re: [BIO] Bounce queue in bio_add_page Message-ID: <20031104090353.GM1477@suse.de> References: <20031101044619.GA15628@gondor.apana.org.au> <20031101100543.GA16682@gondor.apana.org.au> <20031103122500.GA6963@suse.de> <20031103205234.GA17570@gondor.apana.org.au> <20031104084929.GH1477@suse.de> <20031104090325.GA21301@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20031104090325.GA21301@gondor.apana.org.au> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 04 2003, Herbert Xu wrote: > On Tue, Nov 04, 2003 at 09:49:30AM +0100, Jens Axboe wrote: > > > > That could work, but it breaks the rule that counts are always accurate. > > Yes, it means that recount may return a higher value but it is never > lower. Precisely. Historically, that would have caused panics in some drivers even though it is safe :) > I think it should be safe though as recount is not always called (it is > only called if the phys/hw segments exceed the limits). In the cases > where it is not called you may be looking at an overestimate anyway. I think it is safe too, just want to make absolutely sure. -- Jens Axboe