Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261514AbVBCWfc (ORCPT ); Thu, 3 Feb 2005 17:35:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262731AbVBCWbq (ORCPT ); Thu, 3 Feb 2005 17:31:46 -0500 Received: from [211.58.254.17] ([211.58.254.17]:6638 "EHLO hemosu.com") by vger.kernel.org with ESMTP id S261898AbVBCWUU (ORCPT ); Thu, 3 Feb 2005 17:20:20 -0500 Message-ID: <4202A39E.8020004@home-tj.org> Date: Fri, 04 Feb 2005 07:20:14 +0900 From: Tejun Heo User-Agent: Debian Thunderbird 1.0 (X11/20050118) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Bartlomiej Zolnierkiewicz Cc: Jens Axboe , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Subject: Re: [PATCH 2.6.11-rc2 11/29] ide: add ide_drive_t.sleeping References: <20050202024017.GA621@htj.dyndns.org> <20050202025448.GL621@htj.dyndns.org> <58cb370e05020216476a8f403c@mail.gmail.com> <20050203113710.GV5710@suse.de> <58cb370e05020305304e5d504@mail.gmail.com> <20050203133228.GA2816@suse.de> <58cb370e05020305354cbb16ee@mail.gmail.com> In-Reply-To: <58cb370e05020305354cbb16ee@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1769 Lines: 46 Bartlomiej Zolnierkiewicz wrote: > On Thu, 3 Feb 2005 14:32:29 +0100, Jens Axboe wrote: > >>On Thu, Feb 03 2005, Bartlomiej Zolnierkiewicz wrote: >> >>>On Thu, 3 Feb 2005 12:37:10 +0100, Jens Axboe wrote: >>> >>>>On Thu, Feb 03 2005, Bartlomiej Zolnierkiewicz wrote: >>>> >>>>>On Wed, 2 Feb 2005 11:54:48 +0900, Tejun Heo wrote: >>>>> >>>>>>>11_ide_drive_sleeping_fix.patch >>>>>>> >>>>>>> ide_drive_t.sleeping field added. 0 in sleep field used to >>>>>>> indicate inactive sleeping but because 0 is a valid jiffy >>>>>>> value, though slim, there's a chance that something can go >>>>>>> weird. And while at it, explicit jiffy comparisons are >>>>>>> converted to use time_{after|before} macros. >>>>> >>>>>Same question as for "add ide_hwgroup_t.polling" patch. >>>>>AFAICS drive->sleep is either '0' or 'timeout + jiffies' (always > 0) >>>> >>>>Hmm, what if jiffies + timeout == 0? >>> >>>Hm, jiffies is unsigned and timeout is always > 0 >>>but this is still possible if jiffies + timeout wraps, right? >> >>Precisely, if jiffies is exactly 'timeout' away from wrapping to 0 it >>could happen. So I think the fix looks sane. > > > agreed Actually, jiffies is initialized to INITIAL_JIFFIES which is defined in such a way that it overflows after 5 min after boot to help finding bugs related to jiffies wrap. So, the chance of something weird happening in the bugs fixed in patches 11 and 12 isn't that exteremely slim. :-) -- tejun - 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/