Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752640AbYCQPXU (ORCPT ); Mon, 17 Mar 2008 11:23:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751492AbYCQPXJ (ORCPT ); Mon, 17 Mar 2008 11:23:09 -0400 Received: from accolon.hansenpartnership.com ([76.243.235.52]:38108 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751456AbYCQPXH (ORCPT ); Mon, 17 Mar 2008 11:23:07 -0400 Subject: Re: ultrastor.c is a bit-rot From: James Bottomley To: Boaz Harrosh Cc: linux-scsi , Andrew Morton , linux-kernel In-Reply-To: <47DE8736.8020405@panasas.com> References: <47DE8736.8020405@panasas.com> Content-Type: text/plain Date: Mon, 17 Mar 2008 10:23:03 -0500 Message-Id: <1205767383.6767.139.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-3.fc8) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2304 Lines: 61 On Mon, 2008-03-17 at 16:59 +0200, Boaz Harrosh wrote: > Inspecting ultrastor.c it is clear to me that this was never used for > a loooooooooong time. Not since a PC has more then 2^24 bit of memory. > Let me explain below. > > Now I'm not saying it should be fixed. I'm saying that it should be dumped > in the account that it is not used by any one and that it does not work. > > Why it never worked? > ~~~~~~~~~~~~~~~~~~~~~ > > The driver's header says it supports 3 cards > > * 14F - ISA first-party DMA HA with floppy support and WD1003 emulation. > * 24F - EISA Bus Master HA with floppy support and WD1003 emulation. > * 34F - VL-Bus Bus Master HA with floppy support (no WD1003 emulation). > > But Kconfig only specifies ISA. I'm not sure what a VL-Bus is. VL is vesa local ... it was an ISA like graphics bus that was fast and could reach > 16MB. > now the driver defines a static array of structures like this: > > struct { > ... > > struct mscp mscp[ULTRASTOR_MAX_CMDS]; > } config = {0}; > > and allocates a struct mscp in .queuecommand like this: > my_mscp = &config.mscp[mscp_index]; > > it will go on preparing this my_mscp structure including stuffing > some mapped pointers. Lets put that aside for now. > At the very end it will pass this my_mscp structure to the card's > firmware like this: > > /* Store pointer in OGM address bytes */ > outl(isa_virt_to_bus(my_mscp), config.ogm_address); > > Now this is one hell of a smart ISA card. But putting this aside. > > if the machine has more then 2^24 of memory. Then this will never > work, right? or I'm missing it completely? It will definitely work for EISA and VL bus. I think if you analyse the placement of kernel data segments for compiled in drivers, it might also work for ISA too, since I think the pfn will be low enough. It should fail as a module not just because the area will be out of range for ISA, but also because the module data segment is in vmalloc space, so the virt_to_bus assumptions of contiguity could be violated. James -- 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/