On Mon, 2018-11-19 at 12:51 +0900, Damien Le Moal wrote:
> bio->bi_ioc is never set so always NULL. Remove references to it in
> bio_disassociate_task() and in rq_ioc() and delete this field from
> struct bio. With this change, rq_ioc() always returns
> current->io_context without the need for a bio argument. Further
> simplify the code and make it more readable by also removing this
> helper, which also allows to simplify blk_mq_sched_assign_ioc() by
> removing its bio argument.
>
> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
Looks good,
Reviewed-by: Adam Manzanares <adam.manzanares@xxxxxxx>
Reviewed by:
> ---
> block/bio.c | 4 ----
> block/blk-core.c | 2 +-
> block/blk-mq-sched.c | 4 ++--
> block/blk-mq-sched.h | 2 +-
> block/blk-mq.c | 4 ++--
> block/blk.h | 16 ----------------
> include/linux/blk_types.h | 3 +--
> 7 files changed, 7 insertions(+), 28 deletions(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index 4f4d9884443b..03895cc0d74a 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -2027,10 +2027,6 @@ int bio_associate_blkg(struct bio *bio, struct
> blkcg_gq *blkg)
> */
> void bio_disassociate_task(struct bio *bio)
> {
> - if (bio->bi_ioc) {
> - put_io_context(bio->bi_ioc);
> - bio->bi_ioc = NULL;
> - }
> if (bio->bi_css) {
> css_put(bio->bi_css);
> bio->bi_css = NULL;
> diff --git a/block/blk-core.c b/block/blk-core.c
> index d6e8ab9ca99d..492648c96992 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -813,7 +813,7 @@ unsigned int blk_plug_queued_count(struct
> request_queue *q)
>
> void blk_init_request_from_bio(struct request *req, struct bio *bio)
> {
> - struct io_context *ioc = rq_ioc(bio);
> + struct io_context *ioc = current->io_context;
>
> if (bio->bi_opf & REQ_RAHEAD)
> req->cmd_flags |= REQ_FAILFAST_MASK;
> diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
> index d084f731d104..13b8dc332541 100644
> --- a/block/blk-mq-sched.c
> +++ b/block/blk-mq-sched.c
> @@ -31,10 +31,10 @@ void blk_mq_sched_free_hctx_data(struct
> request_queue *q,
> }
> EXPORT_SYMBOL_GPL(blk_mq_sched_free_hctx_data);
>
> -void blk_mq_sched_assign_ioc(struct request *rq, struct bio *bio)
> +void blk_mq_sched_assign_ioc(struct request *rq)
> {
> struct request_queue *q = rq->q;
> - struct io_context *ioc = rq_ioc(bio);
> + struct io_context *ioc = current->io_context;
> struct io_cq *icq;
>
> spin_lock_irq(&q->queue_lock);
> diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
> index 7ff5671bf128..0f719c8532ae 100644
> --- a/block/blk-mq-sched.h
> +++ b/block/blk-mq-sched.h
> @@ -8,7 +8,7 @@
> void blk_mq_sched_free_hctx_data(struct request_queue *q,
> void (*exit)(struct blk_mq_hw_ctx *));
>
> -void blk_mq_sched_assign_ioc(struct request *rq, struct bio *bio);
> +void blk_mq_sched_assign_ioc(struct request *rq);
>
> void blk_mq_sched_request_inserted(struct request *rq);
> bool blk_mq_sched_try_merge(struct request_queue *q, struct bio
> *bio,
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 32b246ed44c0..636f80b96fa6 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -389,8 +389,8 @@ static struct request *blk_mq_get_request(struct
> request_queue *q,
> if (!op_is_flush(data->cmd_flags)) {
> rq->elv.icq = NULL;
> if (e && e->type->ops.prepare_request) {
> - if (e->type->icq_cache && rq_ioc(bio))
> - blk_mq_sched_assign_ioc(rq, bio);
> + if (e->type->icq_cache)
> + blk_mq_sched_assign_ioc(rq);
>
> e->type->ops.prepare_request(rq, bio);
> rq->rq_flags |= RQF_ELVPRIV;
> diff --git a/block/blk.h b/block/blk.h
> index 816a9abb87cd..610948157a5b 100644
> --- a/block/blk.h
> +++ b/block/blk.h
> @@ -254,22 +254,6 @@ void ioc_clear_queue(struct request_queue *q);
>
> int create_task_io_context(struct task_struct *task, gfp_t gfp_mask,
> int node);
>
> -/**
> - * rq_ioc - determine io_context for request allocation
> - * @bio: request being allocated is for this bio (can be %NULL)
> - *
> - * Determine io_context to use for request allocation for @bio. May
> return
> - * %NULL if %current->io_context doesn't exist.
> - */
> -static inline struct io_context *rq_ioc(struct bio *bio)
> -{
> -#ifdef CONFIG_BLK_CGROUP
> - if (bio && bio->bi_ioc)
> - return bio->bi_ioc;
> -#endif
> - return current->io_context;
> -}
> -
> /**
> * create_io_context - try to create task->io_context
> * @gfp_mask: allocation mask
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index dbdbfbd6a987..c0ba1a038ff3 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -174,10 +174,9 @@ struct bio {
> void *bi_private;
> #ifdef CONFIG_BLK_CGROUP
> /*
> - * Optional ioc and css associated with this bio. Put on bio
> + * Optional css associated with this bio. Put on bio
> * release. Read comment on top of bio_associate_current().
> */
> - struct io_context *bi_ioc;
> struct cgroup_subsys_state *bi_css;
> struct blkcg_gq *bi_blkg;
> struct bio_issue bi_issue;
