Re: [PATCH 1/4] block: provide helpers for rq_list manipulation

[Christoph Hellwig <hch@infradead.org>]

On Wed, Oct 13, 2021 at 10:49:34AM -0600, Jens Axboe wrote:
> Instead of open-coding the list additions, traversal, and removal,
> provide a basic set of helpers.
> 
> Suggested-by: Christoph Hellwig <hch@infradead.org>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>  block/blk-mq.c         | 21 +++++----------------
>  include/linux/blk-mq.h | 25 +++++++++++++++++++++++++
>  2 files changed, 30 insertions(+), 16 deletions(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 6dfd3aaa6073..46a91e5fabc5 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -426,10 +426,10 @@ static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
>  			tag = tag_offset + i;
>  			tags &= ~(1UL << i);
>  			rq = blk_mq_rq_ctx_init(data, tag, alloc_time_ns);
> -			rq->rq_next = *data->cached_rq;
> -			*data->cached_rq = rq;
> +			rq_list_add_tail(data->cached_rq, rq);
>  		}

This doesn't seem to match the code in the current for-5.6/block branch.

>  		data->nr_tags -= nr;
> +		return rq_list_pop(data->cached_rq);
>  	} else {

But either way no need for an else after a return.