Re: [PATCH 1/6] scsi: libsas: Add sas_task_find_rq()

[Johannes Thumshirn]

On 28.09.22 14:34, John Garry wrote:
> blk-mq already provides a unique tag per request. Some libsas LLDDs - like
> hisi_sas - already use this tag as the unique per-IO HW tag.
> 
> Add a common function to provide the request associated with a sas_task
> for all libsas LLDDs.
> 
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> ---
>  include/scsi/libsas.h | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
> index f86b56bf7833..bc51756a3317 100644
> --- a/include/scsi/libsas.h
> +++ b/include/scsi/libsas.h
> @@ -644,6 +644,28 @@ static inline bool sas_is_internal_abort(struct sas_task *task)
>  	return task->task_proto == SAS_PROTOCOL_INTERNAL_ABORT;
>  }
>  
> +static inline struct request *sas_task_find_rq(struct sas_task *task)
> +{
> +	struct scsi_cmnd *scmd;
> +
> +	if (!task || !task->uldd_task)
> +		return NULL;

Is anyone actually calling sas_task_find_rq with a NULL task?
That doesn't make a lot of sense from an API POV for me, having
the only argument allowed to be NULL (and not being a *free()
kind of function).

> +
> +	if (task->task_proto & SAS_PROTOCOL_STP_ALL) {
> +		struct ata_queued_cmd *qc;
> +
> +		qc = task->uldd_task;
> +		scmd = qc->scsicmd;
> +	} else {
> +		scmd = task->uldd_task;
> +	}
> +
> +	if (!scmd)
> +		return NULL;
> +
> +	return scsi_cmd_to_rq(scmd);
> +}
> +
>  struct sas_domain_function_template {
>  	/* The class calls these to notify the LLDD of an event. */
>  	void (*lldd_port_formed)(struct asd_sas_phy *);