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null_blk: prevent timer handler running on a different CPU where started 

When irqmode=2 (IRQ completion handler is timer), timer handler should
be called on the same CPU where the timer has been started.

Since completion_queues are per-cpu and the completion handler only
touches completion_queue for local CPU, we need to prevent the handler
from running on a different CPU where the timer has been started.
Otherwise, the IO cannot be completed until another completion handler
is executed on that CPU.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
hifive-unleashed-5.1
Akinobu Mita 2015-06-02 08:35:09 +09:00 committed by Jens Axboe
parent 42483228d4
commit 419c21a3b6
1 changed files with 1 additions and 1 deletions
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2
drivers/block/null_blk.c
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@ -257,7 +257,7 @@ static void null_cmd_end_timer(struct nullb_cmd *cmd)
if (llist_add(&cmd->ll_list, &cq->list)) {
ktime_t kt = ktime_set(0, completion_nsec);
hrtimer_start(&cq->timer, kt, HRTIMER_MODE_REL);
hrtimer_start(&cq->timer, kt, HRTIMER_MODE_REL_PINNED);
}
put_cpu();