Alan Cox wrote:
> +/**
> + * sl82c105_qc_defer - implement serialization
> + * @qc: command
> + *
> + * We must issue one command per host not per channel because
> + * of the reset bug.
> + *
> + * Q: is the scsi host lock sufficient ?
> + */
> +
> +static int sl82c105_qc_defer(struct ata_queued_cmd *qc)
> +{
> + struct ata_host *host = qc->ap->host;
> + int rc;
> +
> + /* First apply the usual rules */
> + rc = ata_std_qc_defer(qc);
> + if (rc != 0)
> + return rc;
> +
> + /* Now apply serialization rules. Only allow a command if the
> + other channel state machine is idle */
> + if (host->port[0] != qc->ap &&
> + host->port[0]->hsm_task_state != HSM_ST_IDLE)
> + return ATA_DEFER_PORT;
> + if (host->port[1] != qc->ap &&
> + host->port[1]->hsm_task_state != HSM_ST_IDLE)
> + return ATA_DEFER_PORT;
> + return 0;
> +}
hsm_task_state is not necessarily protected by host lock. I think
testing ap->qc_active would be better.
--
tejun
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