Re: [PATCH 5/7] blk-mq: defer to the normal submission path for post-flush requests

[Damien Le Moal <dlemoal@kernel.org>]

On 4/17/23 05:09, Christoph Hellwig wrote:
> Requests with the FUA bit on hardware without FUA support need a post
> flush before returning the caller, but they can still be sent using

s/returning/returning to

> the normal I/O path after initializing the flush-related fields and
> end I/O handler.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/blk-flush.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/block/blk-flush.c b/block/blk-flush.c
> index f62e74d9d56bc8..9eda6d46438dba 100644
> --- a/block/blk-flush.c
> +++ b/block/blk-flush.c
> @@ -435,6 +435,17 @@ bool blk_insert_flush(struct request *rq)
>  		 * Queue for normal execution.
>  		 */
>  		return false;
> +	case REQ_FSEQ_DATA | REQ_FSEQ_POSTFLUSH:
> +		/*
> +		 * Initialize the flush fields and completion handler to trigger
> +		 * the post flush, and then just pass the command on.
> +		 */
> +		blk_rq_init_flush(rq);
> +		rq->flush.seq |= REQ_FSEQ_PREFLUSH;

Shouldn't this be REQ_FSEQ_POSTFLUSH ?

> +		spin_lock_irq(&fq->mq_flush_lock);
> +		list_move_tail(&rq->flush.list, &fq->flush_data_in_flight);
> +		spin_unlock_irq(&fq->mq_flush_lock);
> +		return false;
>  	default:
>  		/*
>  		 * Mark the request as part of a flush sequence and submit it