Re: [PATCH v4 10/10] scsi: Implement blk_mq_ops.show_rq()

[Hannes Reinecke <hare@suse.com>]

On 04/22/2017 01:40 AM, Bart Van Assche wrote:
> Show the SCSI CDB, .eh_eflags and .result for pending SCSI commands
> in /sys/kernel/debug/block/*/mq/*/dispatch and */rq_list.
> 
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Martin K. Petersen <martin.petersen@oracle.com>
> Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> Cc: Omar Sandoval <osandov@fb.com>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: <linux-scsi@vger.kernel.org>
> ---
>  drivers/scsi/scsi_lib.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 4a20e6098f7c..90bb269042df 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -2125,6 +2125,16 @@ static void scsi_exit_rq(struct request_queue *q, struct request *rq)
>  	scsi_free_sense_buffer(shost, cmd->sense_buffer);
>  }
>  
> +static void scsi_show_rq(struct seq_file *m, struct request *rq)
> +{
> +	struct scsi_cmnd *cmd = container_of(scsi_req(rq), typeof(*cmd), req);
> +	unsigned int i;
> +
> +	seq_puts(m, ", .cmd =");
> +	for (i = 0; i < cmd->cmd_len; i++)
> +		seq_printf(m, " %02x", cmd->cmnd[i]);
> +}
> +
>  struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
>  {
>  	struct Scsi_Host *shost = sdev->host;
> @@ -2157,6 +2167,7 @@ static const struct blk_mq_ops scsi_mq_ops = {
>  	.queue_rq	= scsi_queue_rq,
>  	.complete	= scsi_softirq_done,
>  	.timeout	= scsi_timeout,
> +	.show_rq	= scsi_show_rq,
>  	.init_request	= scsi_init_request,
>  	.exit_request	= scsi_exit_request,
>  	.map_queues	= scsi_map_queues,
> 
Hmm. Can't say I'm happy with this callback.
And I really would like to see a similar implementation for NVMe.

But if others agree:

Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
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