Re: [PATCH v5 7/8] block: Remove RQF_PREEMPT and BLK_MQ_REQ_PREEMPT

[Can Guo <cang@codeaurora.org>]

On 2020-12-09 13:29, Bart Van Assche wrote:
> Remove flag RQF_PREEMPT and BLK_MQ_REQ_PREEMPT since these are no 
> longer
> used by any kernel code.
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Hannes Reinecke <hare@suse.de>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>

Reviewed-by: Can Guo <cang@codeaurora.org>

> Cc: Can Guo <cang@codeaurora.org>
> Cc: Stanley Chu <stanley.chu@mediatek.com>
> Cc: Alan Stern <stern@rowland.harvard.edu>
> Cc: Ming Lei <ming.lei@redhat.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Cc: Martin Kepplinger <martin.kepplinger@puri.sm>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>  block/blk-core.c       | 7 +++----
>  block/blk-mq-debugfs.c | 1 -
>  block/blk-mq.c         | 2 --
>  include/linux/blk-mq.h | 2 --
>  include/linux/blkdev.h | 6 +-----
>  5 files changed, 4 insertions(+), 14 deletions(-)
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 10696f9fb6ac..a00bce9f46d8 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -424,11 +424,11 @@ EXPORT_SYMBOL(blk_cleanup_queue);
>  /**
>   * blk_queue_enter() - try to increase q->q_usage_counter
>   * @q: request queue pointer
> - * @flags: BLK_MQ_REQ_NOWAIT, BLK_MQ_REQ_PM and/or BLK_MQ_REQ_PREEMPT
> + * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM
>   */
>  int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
>  {
> -	const bool pm = flags & (BLK_MQ_REQ_PM | BLK_MQ_REQ_PREEMPT);
> +	const bool pm = flags & BLK_MQ_REQ_PM;
> 
>  	while (true) {
>  		bool success = false;
> @@ -630,8 +630,7 @@ struct request *blk_get_request(struct
> request_queue *q, unsigned int op,
>  	struct request *req;
> 
>  	WARN_ON_ONCE(op & REQ_NOWAIT);
> -	WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PM |
> -			       BLK_MQ_REQ_PREEMPT));
> +	WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PM));
> 
>  	req = blk_mq_alloc_request(q, op, flags);
>  	if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn)
> diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
> index 3094542e12ae..9336a6f8d6ef 100644
> --- a/block/blk-mq-debugfs.c
> +++ b/block/blk-mq-debugfs.c
> @@ -297,7 +297,6 @@ static const char *const rqf_name[] = {
>  	RQF_NAME(MIXED_MERGE),
>  	RQF_NAME(MQ_INFLIGHT),
>  	RQF_NAME(DONTPREP),
> -	RQF_NAME(PREEMPT),
>  	RQF_NAME(FAILED),
>  	RQF_NAME(QUIET),
>  	RQF_NAME(ELVPRIV),
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index b5880a1fb38d..d50504888b68 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -294,8 +294,6 @@ static struct request *blk_mq_rq_ctx_init(struct
> blk_mq_alloc_data *data,
>  	rq->cmd_flags = data->cmd_flags;
>  	if (data->flags & BLK_MQ_REQ_PM)
>  		rq->rq_flags |= RQF_PM;
> -	if (data->flags & BLK_MQ_REQ_PREEMPT)
> -		rq->rq_flags |= RQF_PREEMPT;
>  	if (blk_queue_io_stat(data->q))
>  		rq->rq_flags |= RQF_IO_STAT;
>  	INIT_LIST_HEAD(&rq->queuelist);
> diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
> index c00e856c6fb1..88af1df94308 100644
> --- a/include/linux/blk-mq.h
> +++ b/include/linux/blk-mq.h
> @@ -446,8 +446,6 @@ enum {
>  	BLK_MQ_REQ_RESERVED	= (__force blk_mq_req_flags_t)(1 << 1),
>  	/* set RQF_PM */
>  	BLK_MQ_REQ_PM		= (__force blk_mq_req_flags_t)(1 << 2),
> -	/* set RQF_PREEMPT */
> -	BLK_MQ_REQ_PREEMPT	= (__force blk_mq_req_flags_t)(1 << 3),
>  };
> 
>  struct request *blk_mq_alloc_request(struct request_queue *q, unsigned 
> int op,
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 639cae2c158b..7d4b746f7e6a 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -79,9 +79,6 @@ typedef __u32 __bitwise req_flags_t;
>  #define RQF_MQ_INFLIGHT		((__force req_flags_t)(1 << 6))
>  /* don't call prep for this one */
>  #define RQF_DONTPREP		((__force req_flags_t)(1 << 7))
> -/* set for "ide_preempt" requests and also for requests for which the 
> SCSI
> -   "quiesce" state must be ignored. */
> -#define RQF_PREEMPT		((__force req_flags_t)(1 << 8))
>  /* vaguely specified driver internal error.  Ignored by the block 
> layer */
>  #define RQF_FAILED		((__force req_flags_t)(1 << 10))
>  /* don't warn about errors */
> @@ -430,8 +427,7 @@ struct request_queue {
>  	unsigned long		queue_flags;
>  	/*
>  	 * Number of contexts that have called blk_set_pm_only(). If this
> -	 * counter is above zero then only RQF_PM and RQF_PREEMPT requests 
> are
> -	 * processed.
> +	 * counter is above zero then only RQF_PM requests are processed.
>  	 */
>  	atomic_t		pm_only;