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Subject: Re: [PATCH v5 3/6] block: Introduce
 blk_queue_get_max_write_zeroes_sectors()
To:     Kirill Tkhai <ktkhai@virtuozzo.com>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, martin.petersen@oracle.com,
        axboe@kernel.dk, agk@redhat.com, snitzer@redhat.com,
        dm-devel@redhat.com, song@kernel.org, tytso@mit.edu,
        adilger.kernel@dilger.ca, Chaitanya.Kulkarni@wdc.com,
        darrick.wong@oracle.com, ming.lei@redhat.com, osandov@fb.com,
        jthumshirn@suse.de, minwoo.im.dev@gmail.com, damien.lemoal@wdc.com,
        andrea.parri@amarulasolutions.com, hare@suse.com, tj@kernel.org,
        ajay.joshi@wdc.com, sagi@grimberg.me, dsterba@suse.com,
        bvanassche@acm.org, dhowells@redhat.com, asml.silence@gmail.com
References: <157968992539.174869.7490844754165043549.stgit@localhost.localdomain>
 <157969068832.174869.10818825289800365633.stgit@localhost.localdomain>
From:   Bob Liu <bob.liu@oracle.com>
Message-ID: <eb2a8ad1-5ac2-db7e-5e47-ee77e10fa49a@oracle.com>
Date:   Sat, 25 Jan 2020 10:38:00 +0800
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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;
>  }
> 
>