[dm-devel] [PATCH V3 03/13] block: add helper of blk_create_io_context

[Keith Busch]

On Wed, Mar 24, 2021 at 08:19:17PM +0800, Ming Lei wrote:
> +static inline void blk_create_io_context(struct request_queue *q)
> +{
> +	/*
> +	 * Various block parts want %current->io_context, so allocate it up
> +	 * front rather than dealing with lots of pain to allocate it only
> +	 * where needed. This may fail and the block layer knows how to live
> +	 * with it.
> +	 */

I think this comment would make more sense if it were placed above the
caller rather than within this function. 

> +	if (unlikely(!current->io_context))
> +		create_task_io_context(current, GFP_ATOMIC, q->node);
> +}
> +
>  static noinline_for_stack bool submit_bio_checks(struct bio *bio)
>  {
>  	struct block_device *bdev = bio->bi_bdev;
> @@ -836,6 +848,8 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
>  		}
>  	}
>  
> +	blk_create_io_context(q);
> +
>  	if (!blk_queue_poll(q))
>  		bio->bi_opf &= ~REQ_HIPRI;
>  
> @@ -876,15 +890,6 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
>  		break;
>  	}
>  
> -	/*
> -	 * Various block parts want %current->io_context, so allocate it up
> -	 * front rather than dealing with lots of pain to allocate it only
> -	 * where needed. This may fail and the block layer knows how to live
> -	 * with it.
> -	 */
> -	if (unlikely(!current->io_context))
> -		create_task_io_context(current, GFP_ATOMIC, q->node);
> -
>  	if (blk_throtl_bio(bio)) {
>  		blkcg_bio_issue_init(bio);
>  		return false;
> -- 
> 2.29.2