Re: [PATCH v8 05/11] block: introduce blk_req_zone_write_trylock

[Hannes Reinecke <hare@suse.de>]

On 4/27/20 1:31 PM, Johannes Thumshirn wrote:
> Introduce blk_req_zone_write_trylock(), which either grabs the write-lock
> for a sequential zone or returns false, if the zone is already locked.
> 
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/blk-zoned.c      | 14 ++++++++++++++
>   include/linux/blkdev.h |  1 +
>   2 files changed, 15 insertions(+)
> 
> diff --git a/block/blk-zoned.c b/block/blk-zoned.c
> index f87956e0dcaf..c822cfa7a102 100644
> --- a/block/blk-zoned.c
> +++ b/block/blk-zoned.c
> @@ -82,6 +82,20 @@ bool blk_req_needs_zone_write_lock(struct request *rq)
>   }
>   EXPORT_SYMBOL_GPL(blk_req_needs_zone_write_lock);
>   
> +bool blk_req_zone_write_trylock(struct request *rq)
> +{
> +	unsigned int zno = blk_rq_zone_no(rq);
> +
> +	if (test_and_set_bit(zno, rq->q->seq_zones_wlock))
> +		return false;
> +
> +	WARN_ON_ONCE(rq->rq_flags & RQF_ZONE_WRITE_LOCKED);
> +	rq->rq_flags |= RQF_ZONE_WRITE_LOCKED;
> +
> +	return true;
> +}
> +EXPORT_SYMBOL_GPL(blk_req_zone_write_trylock);
> +
>   void __blk_req_zone_write_lock(struct request *rq)
>   {
>   	if (WARN_ON_ONCE(test_and_set_bit(blk_rq_zone_no(rq),
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 158641fbc7cd..d6e6ce3dc656 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1737,6 +1737,7 @@ extern int bdev_write_page(struct block_device *, sector_t, struct page *,
>   
>   #ifdef CONFIG_BLK_DEV_ZONED
>   bool blk_req_needs_zone_write_lock(struct request *r
> +bool blk_req_zone_write_trylock(struct request *rq);
>   void __blk_req_zone_write_lock(struct request *rq);
>   void __blk_req_zone_write_unlock(struct request *rq);
>   
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke            Teamlead Storage & Networking
hare@suse.de                               +49 911 74053 688
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