From: Jeff Garzik <jgarzik@pobox.com>
To: Tejun Heo <htejun@gmail.com>
Cc: linux-ide@vger.kernel.org, albertcc@tw.ibm.com
Subject: Re: [PATCH 09/13] libata: fix handling of race between timeout and completion
Date: Thu, 09 Feb 2006 01:21:23 -0500 [thread overview]
Message-ID: <43EADF63.70605@pobox.com> (raw)
In-Reply-To: <20060201153658.GA4311@htj.dyndns.org>
Tejun Heo wrote:
> SCSI EH never invokes ->eh_strategy_handler without any failed
> scsicmd. The only case where qc <-> scmd mismatch occurs is the
> following case.
>
> 1. SCSI issues command (timer activated)
> 2. libata interprets and issues
> 3. time passes
> 4. SCSI timeout occurs, scmd queued for EH
> 5. irq occurs, completes qc. ata_qc_complete() calls qc->complete_fn
> which ends up calling scsi_done(). scsi_done() sees that SCSI
> timer has already expired, so it returns without doing anything
> expecting EH to clean up.
> 6. SCSI EH kicks in, libata ->eh_strategy_handler (ata_scsi_error)
> invoked.
> 7. in libata EH, we have no active qc but scmds to recover.
OK, I agree with your analysis of the problem above.
However... [see next email, commenting on patch #3]
Jeff
next prev parent reply other threads:[~2006-02-09 6:21 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-23 4:09 [PATCHSET] libata: various fixes related to EH, take #2 Tejun Heo
2006-01-23 4:09 ` [PATCH 07/13] SCSI: export scsi_eh_finish_cmd() and scsi_eh_flush_done_q() Tejun Heo
2006-01-23 7:09 ` Jeff Garzik
2006-01-23 7:26 ` Arjan van de Ven
2006-01-23 8:20 ` Tejun Heo
2006-01-23 9:36 ` Christoph Hellwig
2006-01-23 10:05 ` Tejun Heo
2006-01-24 17:11 ` Luben Tuikov
2006-01-24 17:20 ` Arjan van de Ven
2006-01-24 18:25 ` Luben Tuikov
2006-01-24 17:30 ` Jeff Garzik
2006-01-24 18:53 ` Luben Tuikov
2006-01-23 14:52 ` Tejun Heo
2006-01-23 4:09 ` [PATCH 06/13] libata: return AC_ERR_* from issue functions Tejun Heo
2006-01-23 4:09 ` [PATCH 03/13] libata: fix ata_qc_issue() error handling Tejun Heo
2006-01-23 4:09 ` [PATCH 01/13] libata: fold __ata_qc_complete() into ata_qc_free() Tejun Heo
2006-01-27 3:34 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 04/13] ahci: fix err_mask setting in ahci_host_intr Tejun Heo
2006-01-27 3:36 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 05/13] libata: add detailed AC_ERR_* flags Tejun Heo
2006-01-23 4:09 ` [PATCH 02/13] libata: make the owner of a qc responsible for freeing it Tejun Heo
2006-01-23 4:09 ` [PATCH 11/13] libata: implement ATA_FLAG_IN_EH port flag Tejun Heo
2006-01-27 4:00 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 10/13] libata: kill NULL qc handling from ->eng_timeout callbacks Tejun Heo
2006-01-23 4:09 ` [PATCH 09/13] libata: fix handling of race between timeout and completion Tejun Heo
2006-01-27 3:55 ` Jeff Garzik
2006-01-27 3:58 ` Jeff Garzik
2006-02-01 15:36 ` Tejun Heo
2006-02-09 6:21 ` Jeff Garzik [this message]
2006-01-23 4:09 ` [PATCH 13/13] libata: EH / pio tasks synchronization Tejun Heo
2006-01-23 4:09 ` [PATCH 12/13] libata: create pio/atapi task queueing wrappers Tejun Heo
2006-01-27 4:02 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 08/13] libata: implement and apply ata_eh_qc_complete/retry() Tejun Heo
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