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FROMGIT: block: avoid double io accounting for flush request

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For flush request, rq->end_io() may be called two times, one is from
timeout handling(blk_mq_check_expired()), another is from normal
completion(__blk_mq_end_request()).

Move blk_account_io_flush() after flush_rq->ref drops to zero, so
io accounting can be done just once for flush request.

Fixes: b686631865 ("block: add iostat counters for flush requests")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210511152236.763464-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Bug: 188199752
(cherry picked from commit 773cd5fb22e7c61c65c7528a3e1cb5bcbc1408ea git://git.kernel.dk/linux-block/ for-5.14/block)
Signed-off-by: Bart Van Assche <bvanassche@google.com>
Change-Id: I0cbcb35fce831daab99145d2401a6fdeb5d575b4
This commit is contained in:
Ming Lei 2021-05-11 23:22:33 +08:00 • committed by Bart Van Assche
commit d8ef677e32
1 changed files with 1 additions and 2 deletions
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3
block/blk-flush.c
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@ -220,8 +220,6 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
unsigned long flags = 0;
struct blk_flush_queue *fq = blk_get_flush_queue(q, flush_rq->mq_ctx);
blk_account_io_flush(flush_rq);
/* release the tag's ownership to the req cloned from */
spin_lock_irqsave(&fq->mq_flush_lock, flags);
@ -231,6 +229,7 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
return;
}
blk_account_io_flush(flush_rq);
/*
* Flush request has to be marked as IDLE when it is really ended
* because its .end_io() is called from timeout code path too for