linux-kernel - Re: [PATCH RFC v3 18/22] scsi: libsas: Queue SMP commands as requests

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Date:   Thu, 27 Oct 2022 10:36:48 +0900
From:   Damien Le Moal <damien.lemoal@...nsource.wdc.com>
To:     John Garry <john.garry@...wei.com>, axboe@...nel.dk,
        jejb@...ux.ibm.com, martin.petersen@...cle.com,
        jinpu.wang@...ud.ionos.com, hare@...e.de, bvanassche@....org,
        hch@....de, ming.lei@...hat.com, niklas.cassel@....com
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-ide@...r.kernel.org, linux-scsi@...r.kernel.org,
        linuxarm@...wei.com
Subject: Re: [PATCH RFC v3 18/22] scsi: libsas: Queue SMP commands as requests

On 10/25/22 19:18, John Garry wrote:
> Send SMP commands through the block layer so that each command gets a
> unique tag associated.
> 
> Function sas_task_complete_internal() is what the LLDD calls to signal
> that the CQ is complete and this calls into the SCSI midlayer. And then
> sas_blk_end_sync_rq() is called when the request completes.
> 
> Signed-off-by: John Garry <john.garry@...wei.com>
> ---
>  drivers/scsi/libsas/sas_expander.c  | 23 ++++++++---------------
>  drivers/scsi/libsas/sas_init.c      |  3 +++
>  drivers/scsi/libsas/sas_internal.h  |  3 +++
>  drivers/scsi/libsas/sas_scsi_host.c | 16 ++++++++++++++++
>  4 files changed, 30 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
> index e7cb95683522..cc41127ea5cc 100644
> --- a/drivers/scsi/libsas/sas_expander.c
> +++ b/drivers/scsi/libsas/sas_expander.c
> @@ -43,34 +43,27 @@ static int smp_execute_task_sg(struct domain_device *dev,
>  	pm_runtime_get_sync(ha->dev);
>  	mutex_lock(&dev->ex_dev.cmd_mutex);
>  	for (retry = 0; retry < 3; retry++) {
> +		struct request *rq;
> +
>  		if (test_bit(SAS_DEV_GONE, &dev->state)) {
>  			res = -ECOMM;
>  			break;
>  		}
>  
> -		task = sas_alloc_slow_task(GFP_KERNEL);
> +		task = sas_alloc_slow_task_rq(dev, GFP_KERNEL);
>  		if (!task) {
>  			res = -ENOMEM;
>  			break;
>  		}
> -		task->dev = dev;
> +
> +		rq = scsi_cmd_to_rq(task->uldd_task);
> +		rq->timeout = SMP_TIMEOUT*HZ;

Missing spaces around "*"

> +
>  		task->task_proto = dev->tproto;
>  		task->smp_task.smp_req = *req;
>  		task->smp_task.smp_resp = *resp;
>  
> -		task->task_done = sas_task_internal_done;
> -
> -		task->slow_task->timer.function = sas_task_internal_timedout;
> -		task->slow_task->timer.expires = jiffies + SMP_TIMEOUT*HZ;
> -		add_timer(&task->slow_task->timer);
> -
> -		res = i->dft->lldd_execute_task(task, GFP_KERNEL);
> -
> -		if (res) {
> -			del_timer_sync(&task->slow_task->timer);
> -			pr_notice("executing SMP task failed:%d\n", res);
> -			break;
> -		}
> +		blk_execute_rq_nowait(rq, true);
>  
>  		wait_for_completion(&task->slow_task->completion);
>  		res = -ECOMM;
> diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
> index 90e63ff5e966..5f9e71a54799 100644
> --- a/drivers/scsi/libsas/sas_init.c
> +++ b/drivers/scsi/libsas/sas_init.c
> @@ -84,6 +84,7 @@ struct sas_task *sas_alloc_slow_task_rq(struct domain_device *device, gfp_t flag
>  		return NULL;
>  
>  	task->dev = device;
> +	task->task_done = sas_task_complete_internal;
>  
>  	rq = scsi_alloc_request(sdev->request_queue, REQ_OP_DRV_IN,
>  				BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
> @@ -95,6 +96,8 @@ struct sas_task *sas_alloc_slow_task_rq(struct domain_device *device, gfp_t flag
>  	scmd = blk_mq_rq_to_pdu(rq);
>  
>  	task->uldd_task = scmd;
> +
> +	rq->end_io = sas_blk_end_sync_rq;
>  	rq->end_io_data = task;
>  
>  	return task;
> diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
> index f5ae4de382f7..9b58948c57c2 100644
> --- a/drivers/scsi/libsas/sas_internal.h
> +++ b/drivers/scsi/libsas/sas_internal.h
> @@ -104,6 +104,9 @@ int sas_execute_tmf(struct domain_device *device, void *parameter,
>  		    int para_len, int force_phy_id,
>  		    struct sas_tmf_task *tmf);
>  
> +void sas_task_complete_internal(struct sas_task *task);
> +enum rq_end_io_ret sas_blk_end_sync_rq(struct request *rq, blk_status_t error);
> +
>  #ifdef CONFIG_SCSI_SAS_HOST_SMP
>  extern void sas_smp_host_handler(struct bsg_job *job, struct Scsi_Host *shost);
>  #else
> diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
> index b7d1994a8f1b..2c734a87bb7c 100644
> --- a/drivers/scsi/libsas/sas_scsi_host.c
> +++ b/drivers/scsi/libsas/sas_scsi_host.c
> @@ -913,6 +913,13 @@ void sas_task_internal_done(struct sas_task *task)
>  	complete(&task->slow_task->completion);
>  }
>  
> +void sas_task_complete_internal(struct sas_task *task)
> +{
> +	struct scsi_cmnd *scmd = task->uldd_task;
> +
> +	scsi_done(scmd);
> +}
> +
>  void sas_task_internal_timedout(struct timer_list *t)
>  {
>  	struct sas_task_slow *slow = from_timer(slow, t, timer);
> @@ -952,6 +959,15 @@ EXPORT_SYMBOL_GPL(sas_internal_timeout);
>  #define TASK_TIMEOUT			(20 * HZ)
>  #define TASK_RETRY			3
>  
> +enum rq_end_io_ret sas_blk_end_sync_rq(struct request *rq, blk_status_t error)
> +{
> +	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
> +	struct sas_task *task = TO_SAS_TASK(scmd);
> +	complete(&task->slow_task->completion);
> +
> +	return RQ_END_IO_NONE;
> +}
> +
>  static int sas_execute_internal_abort(struct domain_device *device,
>  				      enum sas_internal_abort type, u16 tag,
>  				      unsigned int qid, void *data)

-- 
Damien Le Moal
Western Digital Research