Re: [PATCH 4/5] md/raid1: enable io accounting

[Christoph Hellwig <hch@infradead.org>]

On Tue, May 18, 2021 at 01:32:24PM +0800, Guoqing Jiang wrote:
> For raid1, we record the start time between split bio and clone bio,
> and finish the accounting in the final endio.
> 
> Also introduce start_time in r1bio accordingly.
> 
> Signed-off-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
> ---
>  drivers/md/raid1.c | 11 +++++++++++
>  drivers/md/raid1.h |  1 +
>  2 files changed, 12 insertions(+)
> 
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index ced076ba560e..b08a47523dbb 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -300,6 +300,8 @@ static void call_bio_endio(struct r1bio *r1_bio)
>  	if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
>  		bio->bi_status = BLK_STS_IOERR;
>  
> +	if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
> +		bio_end_io_acct_remapped(bio, r1_bio->start_time, bio->bi_bdev);

This can use bio_end_io_acct.

> +	/*
> +	 * Reuse print_msg, if it is false then a fresh r1_bio is just
> +	 * allocated before.
> +	 */
> +	if (!print_msg && blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
> +		r1_bio->start_time = bio_start_io_acct(bio);
> +

Please rename the print_msg vaiable to something sensible and drop the
comment.