Re: [PATCH v5 3/6] block: Introduce blk_queue_get_max_write_zeroes_sectors()

[Bob Liu <bob.liu@oracle.com>]

On 1/22/20 6:58 PM, Kirill Tkhai wrote:
> This introduces a new primitive, which returns max sectors
> for REQ_OP_WRITE_ZEROES operation.
> @op_flags is unused now, and it will be enabled in next patch.
> 
> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
> ---
>  block/blk-core.c       |    2 +-
>  block/blk-merge.c      |    9 ++++++---
>  include/linux/blkdev.h |    8 +++++++-
>  3 files changed, 14 insertions(+), 5 deletions(-)
> 

Reviewed-by: Bob Liu <bob.liu@oracle.com>

> diff --git a/block/blk-core.c b/block/blk-core.c
> index ac2634bcda1f..2edcd55624f1 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -978,7 +978,7 @@ generic_make_request_checks(struct bio *bio)
>  			goto not_supported;
>  		break;
>  	case REQ_OP_WRITE_ZEROES:
> -		if (!q->limits.max_write_zeroes_sectors)
> +		if (!blk_queue_get_max_write_zeroes_sectors(q, bio->bi_opf))
>  			goto not_supported;
>  		break;
>  	default:
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index 1534ed736363..467b292bc6e8 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -105,15 +105,18 @@ static struct bio *blk_bio_discard_split(struct request_queue *q,
>  static struct bio *blk_bio_write_zeroes_split(struct request_queue *q,
>  		struct bio *bio, struct bio_set *bs, unsigned *nsegs)
>  {
> +	unsigned int max_sectors;
> +
> +	max_sectors = blk_queue_get_max_write_zeroes_sectors(q, bio->bi_opf);
>  	*nsegs = 0;
>  
> -	if (!q->limits.max_write_zeroes_sectors)
> +	if (!max_sectors)
>  		return NULL;
>  
> -	if (bio_sectors(bio) <= q->limits.max_write_zeroes_sectors)
> +	if (bio_sectors(bio) <= max_sectors)
>  		return NULL;
>  
> -	return bio_split(bio, q->limits.max_write_zeroes_sectors, GFP_NOIO, bs);
> +	return bio_split(bio, max_sectors, GFP_NOIO, bs);
>  }
>  
>  static struct bio *blk_bio_write_same_split(struct request_queue *q,
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 23a5850f35f6..264202fa3bf8 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -988,6 +988,12 @@ static inline struct bio_vec req_bvec(struct request *rq)
>  	return mp_bvec_iter_bvec(rq->bio->bi_io_vec, rq->bio->bi_iter);
>  }
>  
> +static inline unsigned int blk_queue_get_max_write_zeroes_sectors(
> +		struct request_queue *q, unsigned int op_flags)
> +{
> +	return q->limits.max_write_zeroes_sectors;
> +}
> +
>  static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
>  						     unsigned int op_flags)
>  {
> @@ -1001,7 +1007,7 @@ static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
>  		return q->limits.max_write_same_sectors;
>  
>  	if (unlikely(op == REQ_OP_WRITE_ZEROES))
> -		return q->limits.max_write_zeroes_sectors;
> +		return blk_queue_get_max_write_zeroes_sectors(q, op_flags);
>  
>  	return q->limits.max_sectors;
>  }
> 
>