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| author |   Tejun Heo <htejun@gmail.com> | 2006-02-10 15:10:48 +0900 |
|---|---|---|
| committer |   Jeff Garzik <jgarzik@pobox.com> | 2006-02-10 06:50:46 -0500 |
| commit | f29841e08fa20a7f2c8bc1b70306975299c66ee7 (patch) | |
| tree | c2f6c87cf79fbd36ec49ea3c2247a382da5d75cc /drivers/scsi | |
| parent | [PATCH] libata: add ATA_QCFLAG_EH_SCHEDULED (diff) | |
| download | linux-dev-f29841e08fa20a7f2c8bc1b70306975299c66ee7.tar.xz linux-dev-f29841e08fa20a7f2c8bc1b70306975299c66ee7.zip | |
[PATCH] libata: implement ata_scsi_timed_out()
Implement ata_scsi_timed_out(), to be used as
scsi_host_template->eh_timed_out callback for all libata drivers.
Without this function, the following race exists.
If a qc completes after SCSI timer expires but before libata EH kicks
in, the qc gets completed but the scsicmd still gets passed to libata
EH resulting in ->eng_timeout invocation with NULL qc, which none is
handling properly.
This patch makes sure that scmd and qc share the same lifetime.
Original idea from Jeff Garzik <jgarzik@pobox.com>.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Diffstat (limited to 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/libata-core.c | 1 | ||||
| -rw-r--r-- | drivers/scsi/libata-scsi.c | 41 |
2 files changed, 42 insertions, 0 deletions
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index 977a53dd1677..d53e0bce2bec 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -4913,6 +4913,7 @@ EXPORT_SYMBOL_GPL(ata_ratelimit); EXPORT_SYMBOL_GPL(ata_busy_sleep); EXPORT_SYMBOL_GPL(ata_scsi_ioctl); EXPORT_SYMBOL_GPL(ata_scsi_queuecmd); +EXPORT_SYMBOL_GPL(ata_scsi_timed_out); EXPORT_SYMBOL_GPL(ata_scsi_error); EXPORT_SYMBOL_GPL(ata_scsi_slave_config); EXPORT_SYMBOL_GPL(ata_scsi_release); diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c index 1df468eb2bf3..d67cc2fb5694 100644 --- a/drivers/scsi/libata-scsi.c +++ b/drivers/scsi/libata-scsi.c @@ -717,6 +717,47 @@ int ata_scsi_slave_config(struct scsi_device *sdev) } /** + * ata_scsi_timed_out - SCSI layer time out callback + * @cmd: timed out SCSI command + * + * Handles SCSI layer timeout. We race with normal completion of + * the qc for @cmd. If the qc is already gone, we lose and let + * the scsi command finish (EH_HANDLED). Otherwise, the qc has + * timed out and EH should be invoked. Prevent ata_qc_complete() + * from finishing it by setting EH_SCHEDULED and return + * EH_NOT_HANDLED. + * + * LOCKING: + * Called from timer context + * + * RETURNS: + * EH_HANDLED or EH_NOT_HANDLED + */ +enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd) +{ + struct Scsi_Host *host = cmd->device->host; + struct ata_port *ap = (struct ata_port *) &host->hostdata[0]; + unsigned long flags; + struct ata_queued_cmd *qc; + enum scsi_eh_timer_return ret = EH_HANDLED; + + DPRINTK("ENTER\n"); + + spin_lock_irqsave(&ap->host_set->lock, flags); + qc = ata_qc_from_tag(ap, ap->active_tag); + if (qc) { + assert(qc->scsicmd == cmd); + qc->flags |= ATA_QCFLAG_EH_SCHEDULED; + qc->err_mask |= AC_ERR_TIMEOUT; + ret = EH_NOT_HANDLED; + } + spin_unlock_irqrestore(&ap->host_set->lock, flags); + + DPRINTK("EXIT, ret=%d\n", ret); + return ret; +} + +/** * ata_scsi_error - SCSI layer error handler callback * @host: SCSI host on which error occurred * |