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block: optimise req_bio_endio() 

First, get rid of an extra branch and chain error checks. Also reshuffle
it with bio_advance(), so it goes closer to the final check, with that
the compiler loads rq->rq_flags only once, and also doesn't reload
bio->bi_iter.bi_size if bio_advance() didn't actually advanced the iter.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-10-19 22:24:12 +01:00 committed by Jens Axboe
parent 859897c3fb
commit 478eb72b81
1 changed files with 7 additions and 9 deletions
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16
block/blk-mq.c
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@ -633,25 +633,23 @@ void blk_mq_free_plug_rqs(struct blk_plug *plug)
static void req_bio_endio(struct request *rq, struct bio *bio,
unsigned int nbytes, blk_status_t error)
{
if (error)
if (unlikely(error)) {
bio->bi_status = error;
if (unlikely(rq->rq_flags & RQF_QUIET))
bio_set_flag(bio, BIO_QUIET);
bio_advance(bio, nbytes);
if (req_op(rq) == REQ_OP_ZONE_APPEND && error == BLK_STS_OK) {
} else if (req_op(rq) == REQ_OP_ZONE_APPEND) {
/*
* Partial zone append completions cannot be supported as the
* BIO fragments may end up not being written sequentially.
*/
if (bio->bi_iter.bi_size)
if (bio->bi_iter.bi_size == nbytes)
bio->bi_status = BLK_STS_IOERR;
else
bio->bi_iter.bi_sector = rq->__sector;
}
bio_advance(bio, nbytes);
if (unlikely(rq->rq_flags & RQF_QUIET))
bio_set_flag(bio, BIO_QUIET);
/* don't actually finish bio if it's part of flush sequence */
if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
bio_endio(bio);