From: Tejun Heo <htejun@gmail.com>
To: petkovbb@gmail.com
Cc: bzolnier@gmail.com, axboe@kernel.dk, linux-ide@vger.kernel.org
Subject: Re: [PATCH 02/15] ide-tape: remove back-to-back REQUEST_SENSE detection
Date: Sun, 19 Apr 2009 16:36:16 +0900 [thread overview]
Message-ID: <49EAD470.50401@gmail.com> (raw)
In-Reply-To: <20090419072829.GA2906@liondog.tnic>
Hello,
Borislav Petkov wrote:
>> No, that's checking whether the _previous_ command was REQUEST_SENSE
>> which is guaranteed to be set if drive->failed_pc is not NULL.
>> drive->pc is set to the current command at the start of
>> ide_tape_issue_pc().
>
> Damn! Now it all falls into place nicely, thanks for clarifying that. My
> original bug analysis was simply plain wrong.
>
> So, drive->pc means two things: the previous command - until the moment
> when it is overwritten with the upcoming command from the current
> request _and_ the current command which is being issued.
And whether the previous pc is accessible or not depends on which
command it actually was and if failed_pc is set, it's guaranteed to be
valid.
> This is all quite b0rked...
Yeah, it's all way too fragile. :-(
--
tejun
next prev parent reply other threads:[~2009-04-19 7:36 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-17 9:33 [PATCHSET pata-2.6] ide: rq->buffer, data, special and misc cleanups, take#2 Tejun Heo
2009-04-17 9:33 ` [PATCH 01/15] block: clear req->errors on bio completion only for fs requests Tejun Heo
2009-04-17 9:33 ` [PATCH 02/15] ide-tape: remove back-to-back REQUEST_SENSE detection Tejun Heo
2009-04-17 10:23 ` Borislav Petkov
2009-04-17 10:35 ` Tejun Heo
2009-04-17 10:40 ` Tejun Heo
2009-04-17 11:03 ` Borislav Petkov
2009-04-17 21:12 ` Tejun Heo
2009-04-17 21:27 ` Mark Lord
2009-04-18 19:48 ` Borislav Petkov
2009-04-18 21:39 ` Tejun Heo
2009-04-19 7:28 ` Borislav Petkov
2009-04-19 7:36 ` Tejun Heo [this message]
2009-04-18 16:51 ` Bartlomiej Zolnierkiewicz
2009-04-18 21:42 ` Tejun Heo
2009-04-17 9:33 ` [PATCH 03/15] ide: use blk_run_queue() instead of blk_start_queueing() Tejun Heo
2009-04-17 9:33 ` [PATCH 04/15] ide: don't set REQ_SOFTBARRIER Tejun Heo
2009-04-17 9:33 ` [PATCH 05/15] ide kill unused ide_cmd->special Tejun Heo
2009-04-17 9:33 ` [PATCH 06/15] ide-cd: clear sense buffer before issuing request sense Tejun Heo
2009-04-17 9:33 ` [PATCH 07/15] ide-floppy: block pc always uses bio Tejun Heo
2009-04-17 9:33 ` [PATCH 08/15] ide-taskfile: don't abuse rq->buffer Tejun Heo
2009-04-17 9:33 ` [PATCH 09/15] ide-atapi: " Tejun Heo
2009-04-17 9:33 ` [PATCH 10/15] ide-cd: " Tejun Heo
2009-04-17 9:33 ` [PATCH 11/15] ide: add helpers for preparing sense requests Tejun Heo
2009-04-17 9:33 ` [PATCH 12/15] ide-cd: convert to using generic sense request Tejun Heo
2009-04-19 9:22 ` Borislav Petkov
2009-04-19 9:28 ` Tejun Heo
2009-04-19 9:30 ` Tejun Heo
2009-04-17 9:33 ` [PATCH 13/15] ide-atapi: convert ide-{floppy,tape} to using preallocated sense buffer Tejun Heo
2009-04-17 9:33 ` [PATCH 14/15] ide-cd,atapi: use bio for internal commands Tejun Heo
2009-04-17 9:33 ` [PATCH 15/15] ide-pm: don't abuse rq->data Tejun Heo
2009-04-18 16:32 ` [PATCHSET pata-2.6] ide: rq->buffer, data, special and misc cleanups, take#2 Bartlomiej Zolnierkiewicz
2009-04-18 20:04 ` Borislav Petkov
2009-04-18 21:43 ` Tejun Heo
2009-04-18 22:04 ` [GIT PATCH " Tejun Heo
2009-04-20 11:47 ` Bartlomiej Zolnierkiewicz
2009-04-20 11:59 ` Tejun Heo
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