Re: [PATCH v3 5/7] scsi: pm8001: Use sas_task_find_rq() for tagging

Damien Le Moal
2022-10-04T22:44:25Z

On 10/4/22 20:27, John Garry wrote:
> The request associated with a scsi command coming from the block layer
> has a unique tag, so use that when possible for getting a CCB.
>
> Unfortunately we don't support reserved commands in the SCSI midlayer yet,
> so in the interim continue to manage those tags internally (along with
> tags for private commands).
>
> Signed-off-by: John Garry <john.garry@huawei.com>
> Reviewed-by: Jack Wang <jinpu.wang@ionos.com>

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

(see the end for a nit)

> ---
> drivers/scsi/pm8001/pm8001_init.c | 12 ++++--------
> drivers/scsi/pm8001/pm8001_sas.c | 13 +++++++++----
> drivers/scsi/pm8001/pm8001_sas.h | 11 ++++++++---
> drivers/scsi/pm8001/pm80xx_hwi.c | 17 +++--------------
> 4 files changed, 24 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
> index 0edc9857a8bd..abb884ddcaf9 100644
> --- a/drivers/scsi/pm8001/pm8001_init.c
> +++ b/drivers/scsi/pm8001/pm8001_init.c
> @@ -196,7 +196,7 @@ static void pm8001_free(struct pm8001_hba_info *pm8001_ha)
> }
> PM8001_CHIP_DISP->chip_iounmap(pm8001_ha);
> flush_workqueue(pm8001_wq);
> - bitmap_free(pm8001_ha->tags);
> + bitmap_free(pm8001_ha->rsvd_tags);
> kfree(pm8001_ha);
> }
>
> @@ -1208,18 +1208,15 @@ static int pm8001_init_ccb_tag(struct pm8001_hba_info *pm8001_ha)
> struct Scsi_Host *shost = pm8001_ha->shost;
> struct device *dev = pm8001_ha->dev;
> u32 max_out_io, ccb_count;
> - u32 can_queue;
> int i;
>
> max_out_io = pm8001_ha->main_cfg_tbl.pm80xx_tbl.max_out_io;
> ccb_count = min_t(int, PM8001_MAX_CCB, max_out_io);
>
> - /* Update to the scsi host*/
> - can_queue = ccb_count - PM8001_RESERVE_SLOT;
> - shost->can_queue = can_queue;
> + shost->can_queue = ccb_count - PM8001_RESERVE_SLOT;
>
> - pm8001_ha->tags = bitmap_zalloc(ccb_count, GFP_KERNEL);
> - if (!pm8001_ha->tags)
> + pm8001_ha->rsvd_tags = bitmap_zalloc(PM8001_RESERVE_SLOT, GFP_KERNEL);
> + if (!pm8001_ha->rsvd_tags)
> goto err_out;
>
> /* Memory region for ccb_info*/
> @@ -1244,7 +1241,6 @@ static int pm8001_init_ccb_tag(struct pm8001_hba_info *pm8001_ha)
> pm8001_ha->ccb_info[i].task = NULL;
> pm8001_ha->ccb_info[i].ccb_tag = PM8001_INVALID_TAG;
> pm8001_ha->ccb_info[i].device = NULL;
> - ++pm8001_ha->tags_num;
> }
>
> return 0;
> diff --git a/drivers/scsi/pm8001/pm8001_sas.c b/drivers/scsi/pm8001/pm8001_sas.c
> index 066dfa9f4683..f46588cd5c73 100644
> --- a/drivers/scsi/pm8001/pm8001_sas.c
> +++ b/drivers/scsi/pm8001/pm8001_sas.c
> @@ -65,9 +65,12 @@ static int pm8001_find_tag(struct sas_task *task, u32 *tag)
> */
> void pm8001_tag_free(struct pm8001_hba_info *pm8001_ha, u32 tag)
> {
> - void *bitmap = pm8001_ha->tags;
> + void *bitmap = pm8001_ha->rsvd_tags;
> unsigned long flags;
>
> + if (tag >= PM8001_RESERVE_SLOT)
> + return;
> +
> spin_lock_irqsave(&pm8001_ha->bitmap_lock, flags);
> __clear_bit(tag, bitmap);
> spin_unlock_irqrestore(&pm8001_ha->bitmap_lock, flags);
> @@ -80,18 +83,20 @@ void pm8001_tag_free(struct pm8001_hba_info *pm8001_ha, u32 tag)
> */
> int pm8001_tag_alloc(struct pm8001_hba_info *pm8001_ha, u32 *tag_out)
> {
> - void *bitmap = pm8001_ha->tags;
> + void *bitmap = pm8001_ha->rsvd_tags;
> unsigned long flags;
> unsigned int tag;
>
> spin_lock_irqsave(&pm8001_ha->bitmap_lock, flags);
> - tag = find_first_zero_bit(bitmap, pm8001_ha->tags_num);
> - if (tag >= pm8001_ha->tags_num) {
> + tag = find_first_zero_bit(bitmap, PM8001_RESERVE_SLOT);
> + if (tag >= PM8001_RESERVE_SLOT) {
> spin_unlock_irqrestore(&pm8001_ha->bitmap_lock, flags);
> return -SAS_QUEUE_FULL;
> }
> __set_bit(tag, bitmap);
> spin_unlock_irqrestore(&pm8001_ha->bitmap_lock, flags);
> +
> + /* reserved tags are in the lower region of the tagset */
> *tag_out = tag;
> return 0;
> }
> diff --git a/drivers/scsi/pm8001/pm8001_sas.h b/drivers/scsi/pm8001/pm8001_sas.h
> index 9acaadf02150..b584e68664d8 100644
> --- a/drivers/scsi/pm8001/pm8001_sas.h
> +++ b/drivers/scsi/pm8001/pm8001_sas.h
> @@ -510,8 +510,7 @@ struct pm8001_hba_info {
> u32 chip_id;
> const struct pm8001_chip_info *chip;
> struct completion *nvmd_completion;
> - int tags_num;
> - unsigned long *tags;
> + unsigned long *rsvd_tags;
> struct pm8001_phy phy[PM8001_MAX_PHYS];
> struct pm8001_port port[PM8001_MAX_PHYS];
> u32 id;
> @@ -737,9 +736,15 @@ pm8001_ccb_alloc(struct pm8001_hba_info *pm8001_ha,
> struct pm8001_device *dev, struct sas_task *task)
> {
> struct pm8001_ccb_info *ccb;
> + struct request *rq = NULL;
> u32 tag;
>
> - if (pm8001_tag_alloc(pm8001_ha, &tag)) {
> + if (task)
> + rq = sas_task_find_rq(task);
> +
> + if (rq) {
> + tag = rq->tag + PM8001_RESERVE_SLOT;
> + } else if (pm8001_tag_alloc(pm8001_ha, &tag)) {
> pm8001_dbg(pm8001_ha, FAIL, "Failed to allocate a tag\n");
> return NULL;
> }
> diff --git a/drivers/scsi/pm8001/pm80xx_hwi.c b/drivers/scsi/pm8001/pm80xx_hwi.c
> index 4484c498bcb6..ed2d65d3749a 100644
> --- a/drivers/scsi/pm8001/pm80xx_hwi.c
> +++ b/drivers/scsi/pm8001/pm80xx_hwi.c
> @@ -4247,24 +4247,13 @@ static int check_enc_sat_cmd(struct sas_task *task)
>
> static u32 pm80xx_chip_get_q_index(struct sas_task *task)
> {
> - struct scsi_cmnd *scmd = NULL;
> + struct request *rq = sas_task_find_rq(task);
> u32 blk_tag;
>
> - if (task->uldd_task) {
> - struct ata_queued_cmd *qc;
> -
> - if (dev_is_sata(task->dev)) {
> - qc = task->uldd_task;
> - scmd = qc->scsicmd;
> - } else {
> - scmd = task->uldd_task;
> - }
> - }
> -
> - if (!scmd)
> + if (!rq)
> return 0;
>
> - blk_tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmd));
> + blk_tag = blk_mq_unique_tag(rq);
> return blk_mq_unique_tag_to_hwq(blk_tag);

Nit: You could simplify:

return blk_mq_unique_tag_to_hwq(blk_mq_unique_tag(rq));

No need for blk_tag variable I think.

> }
>

--
Damien Le Moal
Western Digital Research