Re: [PATCH v2 3/3] libata: use blk taging

[Shaohua Li <shli@fb.com>]

Ping!

On Thu, Dec 18, 2014 at 10:46:22AM -0800, Shaohua Li wrote:
> libata uses its own tag management which is duplication and the
> implementation is poor. And if we switch to blk-mq, tag is build-in.
> It's time to switch to generic taging.
> 
> The SAS driver has its own tag management, and looks we can't directly
> map the host controler tag to SATA tag. So I just bypassed the SAS case.
> 
> Cc: Jens Axboe <axboe@fb.com>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Christoph Hellwig <hch@infradead.org>
> Signed-off-by: Shaohua Li <shli@fb.com>
> ---
>  drivers/ata/libata-core.c | 20 ++++++++++++++------
>  drivers/ata/libata-scsi.c |  4 +++-
>  drivers/ata/libata.h      |  2 +-
>  include/linux/libata.h    |  1 +
>  4 files changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index 5c84fb5..a27d00f 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -1585,8 +1585,9 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
>  	else
>  		tag = 0;
>  
> -	if (test_and_set_bit(tag, &ap->qc_allocated))
> -		BUG();
> +	BUG_ON((!ap->scsi_host && test_and_set_bit(tag, &ap->qc_allocated)) ||
> +		(ap->scsi_host && dev->sdev &&
> +			blk_queue_find_tag(dev->sdev->request_queue, tag)));
>  	qc = __ata_qc_from_tag(ap, tag);
>  
>  	qc->tag = tag;
> @@ -4737,7 +4738,7 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
>   *	None.
>   */
>  
> -static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
> +static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap, int blktag)
>  {
>  	struct ata_queued_cmd *qc = NULL;
>  	unsigned int max_queue = ap->host->n_tags;
> @@ -4747,6 +4748,12 @@ static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
>  	if (unlikely(ap->pflags & ATA_PFLAG_FROZEN))
>  		return NULL;
>  
> +	if (ap->scsi_host) {
> +		qc = __ata_qc_from_tag(ap, blktag);
> +		qc->tag = blktag;
> +		return qc;
> +	}
> +
>  	for (i = 0, tag = ap->last_tag + 1; i < max_queue; i++, tag++) {
>  		tag = tag < max_queue ? tag : 0;
>  
> @@ -4773,12 +4780,12 @@ static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
>   *	None.
>   */
>  
> -struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev)
> +struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev, int blktag)
>  {
>  	struct ata_port *ap = dev->link->ap;
>  	struct ata_queued_cmd *qc;
>  
> -	qc = ata_qc_new(ap);
> +	qc = ata_qc_new(ap, blktag);
>  	if (qc) {
>  		qc->scsicmd = NULL;
>  		qc->ap = ap;
> @@ -4812,7 +4819,8 @@ void ata_qc_free(struct ata_queued_cmd *qc)
>  	tag = qc->tag;
>  	if (likely(ata_tag_valid(tag))) {
>  		qc->tag = ATA_TAG_POISON;
> -		clear_bit(tag, &ap->qc_allocated);
> +		if (!ap->scsi_host)
> +			clear_bit(tag, &ap->qc_allocated);
>  	}
>  }
>  
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index e364e86..94339c2 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -756,7 +756,7 @@ static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
>  {
>  	struct ata_queued_cmd *qc;
>  
> -	qc = ata_qc_new_init(dev);
> +	qc = ata_qc_new_init(dev, cmd->request->tag);
>  	if (qc) {
>  		qc->scsicmd = cmd;
>  		qc->scsidone = cmd->scsi_done;
> @@ -3666,6 +3666,8 @@ int ata_scsi_add_hosts(struct ata_host *host, struct scsi_host_template *sht)
>  		 */
>  		shost->max_host_blocked = 1;
>  
> +		scsi_init_shared_tag_map(shost, host->n_tags);
> +
>  		rc = scsi_add_host_with_dma(ap->scsi_host,
>  						&ap->tdev, ap->host->dev);
>  		if (rc)
> diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
> index 5f4e0cc..4040513 100644
> --- a/drivers/ata/libata.h
> +++ b/drivers/ata/libata.h
> @@ -63,7 +63,7 @@ extern struct ata_link *ata_dev_phys_link(struct ata_device *dev);
>  extern void ata_force_cbl(struct ata_port *ap);
>  extern u64 ata_tf_to_lba(const struct ata_taskfile *tf);
>  extern u64 ata_tf_to_lba48(const struct ata_taskfile *tf);
> -extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
> +extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev, int tag);
>  extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
>  			   u64 block, u32 n_block, unsigned int tf_flags,
>  			   unsigned int tag);
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 2d18241..5f1c5606 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -1344,6 +1344,7 @@ extern struct device_attribute *ata_common_sdev_attrs[];
>  	.ioctl			= ata_scsi_ioctl,		\
>  	.queuecommand		= ata_scsi_queuecmd,		\
>  	.can_queue		= ATA_DEF_QUEUE,		\
> +	.tag_alloc_policy	= BLK_TAG_ALLOC_RR,		\
>  	.this_id		= ATA_SHT_THIS_ID,		\
>  	.cmd_per_lun		= ATA_SHT_CMD_PER_LUN,		\
>  	.emulated		= ATA_SHT_EMULATED,		\
> -- 
> 1.8.1
>