Re: [PATCH 1/2] scsi: Add helper code so transport classes/driver can control queueing

[James Smart <James.Smart@Emulex.Com>]

michaelc@cs.wisc.edu wrote:
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index f6a9fe0..06b7b59 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -206,6 +206,16 @@ struct scsi_target {
>  						 * for the device at a time. */
>  	unsigned int		pdt_1f_for_no_lun;	/* PDT = 0x1f */
>  						/* means no lun present */
> +	/* commands actually active on LLD. protected by host lock. */
> +	unsigned int		target_busy;
> +	/*
> +	 * LLDs should set this in the slave_alloc host template callout.
> +	 * If set to zero then there is not limit.
> +	 */
> +	unsigned int		can_queue;
> +	unsigned int		target_blocked;
> +	unsigned int		max_target_blocked;
> +#define SCSI_DEFAULT_TARGET_BLOCKED	3
>  
>  	char			scsi_level;
>  	struct execute_work	ew;

Mike,

The starget->can_queue value should come from the targets device_list entry, not the LLD.

To complete this fully, if the LLD had a per-target resource restriction (which I doubt
would be target-specific), it should set a value within the shost template much along the
lines of the shost->can_queue. The starget->can_queue would then be the
min(shost->tgt_can_queue, device_list->tgt_can_queue) and would be set in the scsi_scan code.

-- james s