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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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Chaitanya Kulkarni 2019-08-22 21:45:15 -07:00 committed by Jens Axboe
parent d4b186ed22
commit adb8428479
1 changed files with 25 additions and 14 deletions
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39
drivers/block/null_blk_main.c
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@ -1133,28 +1133,39 @@ static void null_restart_queue_async(struct nullb *nullb)
blk_mq_start_stopped_hw_queues(q, true);
}
static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd)
{
struct nullb_device *dev = cmd->nq->dev;
struct nullb *nullb = dev->nullb;
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) {
null_stop_queue(nullb);
/* race with timer */
if (atomic_long_read(&nullb->cur_bytes) > 0)
null_restart_queue_async(nullb);
/* requeue request */
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)) {
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) {
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 = null_handle_throttled(cmd);
if (sts != BLK_STS_OK)
return sts;
}
if (op == REQ_OP_FLUSH) {