Re: [PATCH RFC v2 06/18] libata-scsi: Add ata_scsi_queue_internal()

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

On 6/9/22 19:29, John Garry wrote:
> Add a function to handle queued ATA internal SCSI cmnds - does much the
> same as ata_exec_internal_sg() does (which will be fixed up later to
> actually queue internal cmnds through this function).
> 
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
>  drivers/ata/libata-scsi.c | 47 ++++++++++++++++++++++++++++++++++++++-
>  include/linux/libata.h    |  6 +++++
>  2 files changed, 52 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index 42cecf95a4e5..baac35dd17ca 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -3963,6 +3963,49 @@ static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd)
>  	return NULL;
>  }
>  
> +static unsigned int ata_scsi_queue_internal(struct scsi_cmnd *scmd,
> +					    struct ata_device *dev)
> +{
> +	struct ata_link *link = dev->link;
> +	struct ata_port *ap = link->ap;
> +	struct ata_queued_cmd *qc;
> +
> +	/* no internal command while frozen */
> +	if (ap->pflags & ATA_PFLAG_FROZEN)
> +		goto did_err;
> +
> +	/* initialize internal qc */
> +	qc = __ata_qc_from_tag(ap, ATA_TAG_INTERNAL);
> +	link->preempted_tag = link->active_tag;
> +	link->preempted_sactive = link->sactive;
> +	ap->preempted_qc_active = ap->qc_active;
> +	ap->preempted_nr_active_links = ap->nr_active_links;
> +	link->active_tag = ATA_TAG_POISON;
> +	link->sactive = 0;
> +	ap->qc_active = 0;
> +	ap->nr_active_links = 0;> +
> +	if (qc->dma_dir != DMA_NONE) {
> +		int n_elem;
> +
> +		n_elem = 1;
> +		qc->n_elem = n_elem;
> +		qc->sg = scsi_sglist(scmd);
> +		qc->nbytes = qc->sg->length;
> +		ata_sg_init(qc, qc->sg, n_elem);
> +	}
> +
> +	scmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
> +
> +	ata_qc_issue(qc);
> +
> +	return 0;
> +did_err:
> +	scmd->result = (DID_ERROR << 16);
> +	scsi_done(scmd);
> +	return 0;
> +}
> +
>  int __ata_scsi_queuecmd(struct scsi_cmnd *scmd, struct ata_device *dev)
>  {
>  	u8 scsi_op = scmd->cmnd[0];
> @@ -3971,7 +4014,9 @@ int __ata_scsi_queuecmd(struct scsi_cmnd *scmd, struct ata_device *dev)
>  	if (unlikely(!scmd->cmd_len))
>  		goto bad_cdb_len;
>  
> -	if (dev->class == ATA_DEV_ATA || dev->class == ATA_DEV_ZAC) {
> +	if (scsi_is_reserved_cmd(scmd)) {
> +		return ata_scsi_queue_internal(scmd, dev);
> +	} else if (dev->class == ATA_DEV_ATA || dev->class == ATA_DEV_ZAC) {

No need for the else here.

>  		if (unlikely(scmd->cmd_len > dev->cdb_len))
>  			goto bad_cdb_len;
>  
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 732de9014626..43f4bcfe9a5f 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -767,7 +767,9 @@ struct ata_link {
>  
>  	struct device		tdev;
>  	unsigned int		active_tag;	/* active tag on this link */
> +	unsigned int		preempted_tag;
>  	u32			sactive;	/* active NCQ commands */
> +	u32			preempted_sactive;
>  
>  	unsigned int		flags;		/* ATA_LFLAG_xxx */
>  
> @@ -861,6 +863,10 @@ struct ata_port {
>  #ifdef CONFIG_ATA_ACPI
>  	struct ata_acpi_gtm	__acpi_init_gtm; /* use ata_acpi_init_gtm() */
>  #endif
> +
> +	u64 preempted_qc_active;
> +	int preempted_nr_active_links;
> +
>  	/* owned by EH */
>  	u8			sector_buf[ATA_SECT_SIZE] ____cacheline_aligned;
>  };


-- 
Damien Le Moal
Western Digital Research