Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935517AbZDCTvD (ORCPT ); Fri, 3 Apr 2009 15:51:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765369AbZDCTuk (ORCPT ); Fri, 3 Apr 2009 15:50:40 -0400 Received: from mail-fx0-f158.google.com ([209.85.220.158]:62482 "EHLO mail-fx0-f158.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752813AbZDCTue (ORCPT ); Fri, 3 Apr 2009 15:50:34 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:subject:date:user-agent:cc:references:in-reply-to :mime-version:content-disposition:message-id:content-type :content-transfer-encoding; b=nPOklktMfiF6nIcLpRC8nigPmzgAxd0irVMsBWTpJUgNPjej3HroYULaoVk/IIEck1 ZMWVkGa2Zg1XMvBnLOQEDnDAp9bw3pK34ORTU62gpRg1MDyMFHuy6zfl0J/Je9ywukNL hT9URhny0EL0/CyPyceReGfW4ub2pB3zbI8Ek= From: Bartlomiej Zolnierkiewicz To: petkovbb@gmail.com Subject: Re: [PATCH 2/3] ide-cd: cleanup cdrom_decode_status Date: Fri, 3 Apr 2009 21:39:38 +0200 User-Agent: KMail/1.11.1 (Linux/2.6.29-next-20090402; KDE/4.2.1; i686; ; ) Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org References: <1238655519-10074-2-git-send-email-petkovbb@gmail.com> <200904031241.44597.bzolnier@gmail.com> <9ea470500904030703k9285e0eye5487f825df77e6@mail.gmail.com> In-Reply-To: <9ea470500904030703k9285e0eye5487f825df77e6@mail.gmail.com> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200904032139.38756.bzolnier@gmail.com> Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7158 Lines: 230 On Friday 03 April 2009, Borislav Petkov wrote: > On Fri, Apr 3, 2009 at 12:41 PM, Bartlomiej Zolnierkiewicz > wrote: > > On Friday 03 April 2009, Borislav Petkov wrote: > >> Hi, > >> > >> On Fri, Apr 03, 2009 at 01:08:39AM +0200, Bartlomiej Zolnierkiewicz wrote: > >> > On Thursday 02 April 2009, Borislav Petkov wrote: > >> > > - have (almost) equal handling of commands based solely on sense_key > >> > > >> > I'm having a VERY hard time trying to review this patch because at > >> > the same time that codepaths were merged if()s were replaced by switch() > >> > which in turn resulted in change of intendation... on top of that > >> > the patch description is very vague about this part of the changes... > >> > >> I completely and exactly understand what you are saying :), I thought so > >> too when I looked at the diffs yesterday. Well, if it's any consolation, the > >> patches've been tested so they seem to work :). Anyway, split version coming > >> up... > > > > The split version looks exactly the same except ide_cd_breathe() change > > when it comes to the main part. > > > > Did you send the wrong version by any chance? > > No, but I can't split those changes anymore logically. The switch-case handles > the differentiation based on the sense_key and as such cannot be broken down > anymore without doing some weird stuff and possibly introducing more bugs and Since this didn't convince me... > breaking bisectability. Completely hypothetically: wouldn't a before-after > juxtaposition of the change make reviewing more easier, for example you > apply the patch on a different branch and compare the before and the after > version? ...and this would make me spend a whole weekend trying to track down every little change in code's behavior I went ahead and re-did your patch splitting it on a more fine-grained logical changes (posted in separate patchset, while at it I also fixed REQ_QUIET handling for fs requests). After that I did a diff between ide-cd.c.old_patch and ide-cd.c.new_patchset and besides some trivial differences I indeed found some subtle problems... --- ide-cd.c.old_patch 2009-04-03 18:50:23.000000000 +0200 +++ ide-cd.c.new_patchset 2009-04-03 21:12:02.000000000 +0200 @@ -311,7 +311,7 @@ { ide_hwif_t *hwif = drive->hwif; struct request *rq = hwif->rq; - int err, sense_key, do_end_request; + int err, sense_key, do_end_request = 0; /* get the IDE error register */ err = ide_read_error(drive); @@ -331,90 +331,104 @@ return 2; } - /* if we got an error, pass CHECK_CONDITION as the scsi status byte */ + /* if we got an error, pass CHECK_CONDITION as the SCSI status byte */ if (blk_pc_request(rq) && !rq->errors) rq->errors = SAM_STAT_CHECK_CONDITION; if (blk_noretry_request(rq)) - do_end_request = 1; + do_end_request = 1; switch (sense_key) { case NOT_READY: - if (blk_fs_request(rq) && (rq_data_dir(rq) == WRITE)) { + if (blk_fs_request(rq) == 0 || rq_data_dir(rq) == READ) { + cdrom_saw_media_change(drive); + + if (blk_fs_request(rq) && + (rq->cmd_flags & REQ_QUIET) == 0) + printk(KERN_ERR PFX "%s: tray open\n", + drive->name); + } else { if (ide_cd_breathe(drive, rq)) return 1; - } else { - cdrom_saw_media_change(drive); - printk(KERN_ERR PFX "%s: tray open\n", drive->name); original code didn't spam logs for pc requests } do_end_request = 1; break; - case UNIT_ATTENTION: cdrom_saw_media_change(drive); - if (blk_pc_request(rq) || rq->cmd_type == REQ_TYPE_ATA_PC) + + if (blk_fs_request(rq) == 0) return 0; + /* + * Arrange to retry the request but be sure to give up if we've + * retried too many times. + */ + if (++rq->errors > ERROR_MAX) + do_end_request = 1; break; - case ILLEGAL_REQUEST: - case DATA_PROTECT: /* - * Don't print error message for this condition since SFF8090i + * Don't print error message for this condition -- SFF8090i * indicates that 5/24/00 is the correct response to a request * to close the tray if the drive doesn't have that capability. * * cdrom_log_sense() knows this! */ - if (rq->cmd[0] != GPCMD_START_STOP_UNIT) { + if (rq->cmd[0] == GPCMD_START_STOP_UNIT) this was checked only for ILLEGAL_REQUEST and not DATA_PROTECT + break; + /* fall-through */ + case DATA_PROTECT: + /* + * No point in retrying after an illegal request or data + * protect error. + */ + if ((rq->cmd_flags & REQ_QUIET) == 0) ide_dump_status(drive, "command error", stat); original code respected REQ_QUIET for pc requests - do_end_request = 1; - } + do_end_request = 1; break; - case MEDIUM_ERROR: /* - * No point in re-trying a zillion times on a bad sector. If we - * got here the error is not correctable. + * No point in re-trying a zillion times on a bad sector. + * If we got here the error is not correctable. */ - ide_dump_status(drive, "media error (bad sector)", stat); + if ((rq->cmd_flags & REQ_QUIET) == 0) + ide_dump_status(drive, "media error " + "(bad sector)", stat); ditto do_end_request = 1; break; - case BLANK_CHECK: - /* disk appears blank ?? */ - ide_dump_status(drive, "media error (blank)", stat); + /* disk appears blank? */ + if ((rq->cmd_flags & REQ_QUIET) == 0) + ide_dump_status(drive, "media error (blank)", + stat); ditto do_end_request = 1; break; - default: + if (blk_fs_request(rq) == 0) + break; if (err & ~ATA_ABORTED) { /* go to the default handler for other errors */ ide_error(drive, "cdrom_decode_status", stat); return 1; we can think about doing this also for pc requests but original code didn't do it so we shouldn't mix it with purely cleanup changes - } - - if (!(rq->cmd_flags & REQ_QUIET)) { - ide_dump_status(drive, "command error", stat); - blk_dump_rq_flags(rq, PFX "failing rq"); - } - - do_end_request = 1; this looks like a real regression -- in such situation original code ended fs requests only if (++rq->errors > ERROR_MAX) - break; + } else if (++rq->errors > ERROR_MAX) + /* we've racked up too many retries, abort */ + do_end_request = 1; } - /* we've racked up too many retries, abort */ - if (++rq->errors > ERROR_MAX) + if (blk_fs_request(rq) == 0) { + rq->cmd_flags |= REQ_FAILED; do_end_request = 1; + } - if (do_end_request) { - rq->cmd_flags |= REQ_FAILED; we may set this flag also for fs requests but separate patch is preferred + /* + * End a request through request sense analysis when we have sense data. + * We need this in order to perform end of media processing. + */ + if (do_end_request) goto end_request; - } - /* If we got a CHECK_CONDITION status, queue a request sense command. */ + /* if we got a CHECK_CONDITION status, queue a request sense command */ if (stat & ATA_ERR) cdrom_queue_request_sense(drive, NULL, NULL); - return 1; end_request: -- 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/