From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761867AbYGOPsh (ORCPT ); Tue, 15 Jul 2008 11:48:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761289AbYGOPrx (ORCPT ); Tue, 15 Jul 2008 11:47:53 -0400 Received: from mx1.redhat.com ([66.187.233.31]:53224 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755244AbYGOPrw (ORCPT ); Tue, 15 Jul 2008 11:47:52 -0400 Date: Tue, 15 Jul 2008 11:46:46 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@devserv.devel.redhat.com To: FUJITA Tomonori cc: jens.axboe@oracle.com, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, davem@davemloft.net, linux-parisc@vger.kernel.org Subject: Re: [PATCH] block: fix q->max_segment_size checking in blk_recalc_rq_segments about VMERGE In-Reply-To: <20080716003047P.fujita.tomonori@lab.ntt.co.jp> Message-ID: References: <20080715231956A.fujita.tomonori@lab.ntt.co.jp> <20080716003047P.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> Even if we fix it now, the question is: how long it will stay fixed? Until >> someone makes another change to struct device that restricts boundaries on >> some wacky hardware. > > I'm not sure how the boundary restriction of a device can break > the VMERGE accounting. Because block layer code doesn't know anything about the device, pci access restrictions and so on. Someone already broken DaveM's Sparc64 merging by adding boundaries (it was broken even before, but these boundary checks made it worse). Mikulas