From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764654AbXKOLgy (ORCPT ); Thu, 15 Nov 2007 06:36:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752228AbXKOLgq (ORCPT ); Thu, 15 Nov 2007 06:36:46 -0500 Received: from brick.kernel.dk ([87.55.233.238]:19042 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751049AbXKOLgp (ORCPT ); Thu, 15 Nov 2007 06:36:45 -0500 Date: Thu, 15 Nov 2007 12:35:21 +0100 From: Jens Axboe To: Rusty Russell Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Attempt to get eject failures back to ioctl(CDROMEJECT) Message-ID: <20071115113521.GB5035@kernel.dk> References: <200711141739.46960.rusty@rustcorp.com.au> <200711151335.53053.rusty@rustcorp.com.au> <20071115084705.GE638@kernel.dk> <200711152232.02522.rusty@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200711152232.02522.rusty@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 15 2007, Rusty Russell wrote: > On Thursday 15 November 2007 19:47:05 Jens Axboe wrote: > > On Thu, Nov 15 2007, Rusty Russell wrote: > > > If blk_rq_map_sg returns more than was allocated, it's a bug, and > > > something's already been overwritten. BUG_ON() is probably the right > > > thing here. > > > > It really just means that it mapped more segments than the block layer > > said it would. Usually that wont overwrite memory here since scsi rounds > > up on allocating the sg list, but it indeed can. Similar code has been > > in scsi_lib.c for ages, I'd suggest covering that in the same patch. > > Good point. I assume that you've not seen these printks in recent memory? I have not, they usually show up if we have bugs in the merge accounting logic in the block layer (the merge functions and blk_rq_map_sg() not agreeing). It's been ages since that was an issue, so I'm fine with the bug. > This covers both cases: > > Subject: [PATCH] scsi: BUG_ON() impossible condition. You can add my Acked-by: Jens Axboe when you pass it through James, it should go in that way. -- Jens Axboe