Re: [PATCH v5 09/10] blk-mq: Add blk_mq_ops.show_rq()

[Omar Sandoval <osandov@osandov.com>]

On Tue, Apr 25, 2017 at 01:37:44PM -0700, Bart Van Assche wrote:
> This new callback function will be used in the next patch to show
> more information about SCSI requests.

Reviewed-by: Omar Sandoval <osandov@fb.com>

> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Omar Sandoval <osandov@fb.com>
> Cc: Hannes Reinecke <hare@suse.com>
> ---
>  block/blk-mq-debugfs.c | 6 +++++-
>  include/linux/blk-mq.h | 8 ++++++++
>  2 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
> index ac39093c4ef7..bcd2a7d4a3a5 100644
> --- a/block/blk-mq-debugfs.c
> +++ b/block/blk-mq-debugfs.c
> @@ -311,6 +311,7 @@ static const char *const rqf_name[] = {
>  static int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
>  {
>  	struct request *rq = list_entry_rq(v);
> +	const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
>  	const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
>  
>  	seq_printf(m, "%p {.op=", rq);
> @@ -324,8 +325,11 @@ static int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
>  	seq_puts(m, ", .rq_flags=");
>  	blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
>  		       ARRAY_SIZE(rqf_name));
> -	seq_printf(m, ", .tag=%d, .internal_tag=%d}\n", rq->tag,
> +	seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
>  		   rq->internal_tag);
> +	if (mq_ops->show_rq)
> +		mq_ops->show_rq(m, rq);
> +	seq_puts(m, "}\n");
>  	return 0;
>  }
>  
> diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
> index 0c4dadb85f62..32bd8eb5ba67 100644
> --- a/include/linux/blk-mq.h
> +++ b/include/linux/blk-mq.h
> @@ -142,6 +142,14 @@ struct blk_mq_ops {
>  	reinit_request_fn	*reinit_request;
>  
>  	map_queues_fn		*map_queues;
> +
> +#ifdef CONFIG_BLK_DEBUG_FS
> +	/*
> +	 * Used by the debugfs implementation to show driver-specific
> +	 * information about a request.
> +	 */
> +	void (*show_rq)(struct seq_file *m, struct request *rq);
> +#endif
>  };
>  
>  enum {
> -- 
> 2.12.2
>