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Commit adb84284 authored by Chaitanya Kulkarni's avatar Chaitanya Kulkarni Committed by Jens Axboe
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null_blk: create a helper for throttling 



This patch creates a helper for handling throttling code in the
null_handle_cmd().

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d4b186ed

drivers/block/null_blk_main.c

+25 −14
Original line number Diff line number Diff line
@@ -1133,28 +1133,39 @@ static void null_restart_queue_async(struct nullb *nullb) 
		blk_mq_start_stopped_hw_queues(q, true);

}



static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,

				    sector_t nr_sectors, enum req_opf op)

static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd)

{

	struct nullb_device *dev = cmd->nq->dev;

	struct nullb *nullb = dev->nullb;

	int err = 0;



	if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {

	blk_status_t sts = BLK_STS_OK;

	struct request *rq = cmd->rq;



	if (!hrtimer_active(&nullb->bw_timer))

		hrtimer_restart(&nullb->bw_timer);



		if (atomic_long_sub_return(blk_rq_bytes(rq),

				&nullb->cur_bytes) < 0) {

	if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) {

		null_stop_queue(nullb);

		/* race with timer */

		if (atomic_long_read(&nullb->cur_bytes) > 0)

			null_restart_queue_async(nullb);

		/* requeue request */

			return BLK_STS_DEV_RESOURCE;

		sts = BLK_STS_DEV_RESOURCE;

	}

	return sts;

}



static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,

				    sector_t nr_sectors, enum req_opf op)

{

	struct nullb_device *dev = cmd->nq->dev;

	struct nullb *nullb = dev->nullb;

	blk_status_t sts;

	int err = 0;



	if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {

		sts = null_handle_throttled(cmd);

		if (sts != BLK_STS_OK)

			return sts;

	}



	if (op == REQ_OP_FLUSH) {