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blk-mq: ensure mq_ops ->poll() is entered at least once 

Right now we immediately bail if need_resched() is true, but
we need to do at least one loop in case we have entries waiting.
So just invert the need_resched() check, putting it at the
bottom of the loop.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
Jens Axboe 2018-11-13 21:32:10 -07:00
parent 0a1b8b87d0
commit aa61bec30e
1 changed files with 2 additions and 2 deletions
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4
block/blk-mq.c
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@ -3375,7 +3375,7 @@ static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
hctx->poll_considered++;
state = current->state;
while (!need_resched()) {
do {
int ret;
hctx->poll_invoked++;
@ -3395,7 +3395,7 @@ static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
if (ret < 0 || !spin)
break;
cpu_relax();
}
} while (!need_resched());
__set_current_state(TASK_RUNNING);
return 0;