[dm-devel] [PATCH 3/5] block: remove the request_queue argument to the block_split tracepoint

[Damien Le Moal]

On 2020/12/01 3:09, Christoph Hellwig wrote:
> The request_queue can trivially be derived from the bio.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>  block/blk-merge.c            |  2 +-
>  drivers/md/dm.c              |  2 +-
>  include/trace/events/block.h | 14 ++++++--------
>  kernel/trace/blktrace.c      |  5 ++---
>  4 files changed, 10 insertions(+), 13 deletions(-)
> 
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index 1a46d5bbd399e3..4071daa88a5eaf 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -338,7 +338,7 @@ void __blk_queue_split(struct bio **bio, unsigned int *nr_segs)
>  		split->bi_opf |= REQ_NOMERGE;
>  
>  		bio_chain(split, *bio);
> -		trace_block_split(q, split, (*bio)->bi_iter.bi_sector);
> +		trace_block_split(split, (*bio)->bi_iter.bi_sector);
>  		submit_bio_noacct(*bio);
>  		*bio = split;
>  	}
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index ed7e836efbcdbc..9a5bd90779c7c4 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -1612,7 +1612,7 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
>  				part_stat_unlock();
>  
>  				bio_chain(b, bio);
> -				trace_block_split(md->queue, b, bio->bi_iter.bi_sector);
> +				trace_block_split(b, bio->bi_iter.bi_sector);
>  				ret = submit_bio_noacct(bio);
>  				break;
>  			}
> diff --git a/include/trace/events/block.h b/include/trace/events/block.h
> index 506c29dc7c76fd..b415e4cba84304 100644
> --- a/include/trace/events/block.h
> +++ b/include/trace/events/block.h
> @@ -411,21 +411,19 @@ DEFINE_EVENT(block_unplug, block_unplug,
>  
>  /**
>   * block_split - split a single bio struct into two bio structs
> - * @q: queue containing the bio
>   * @bio: block operation being split
>   * @new_sector: The starting sector for the new bio
>   *
> - * The bio request @bio in request queue @q needs to be split into two
> - * bio requests. The newly created @bio request starts at
> - * @new_sector. This split may be required due to hardware limitation
> - * such as operation crossing device boundaries in a RAID system.
> + * The bio request @bio needs to be split into two bio requests.  The newly
> + * created @bio request starts at @new_sector. This split may be required due to
> + * hardware limitations such as operation crossing device boundaries in a RAID
> + * system.
>   */
>  TRACE_EVENT(block_split,
>  
> -	TP_PROTO(struct request_queue *q, struct bio *bio,
> -		 unsigned int new_sector),
> +	TP_PROTO(struct bio *bio, unsigned int new_sector),
>  
> -	TP_ARGS(q, bio, new_sector),
> +	TP_ARGS(bio, new_sector),
>  
>  	TP_STRUCT__entry(
>  		__field( dev_t,		dev				)
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index 7ab88e00c15765..3ca6d62114f461 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -970,10 +970,9 @@ static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
>  	rcu_read_unlock();
>  }
>  
> -static void blk_add_trace_split(void *ignore,
> -				struct request_queue *q, struct bio *bio,
> -				unsigned int pdu)
> +static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
>  {
> +	struct request_queue *q = bio->bi_disk->queue;
>  	struct blk_trace *bt;
>  
>  	rcu_read_lock();
> 

Looks good.

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

-- 
Damien Le Moal
Western Digital Research