From 51d798cdb5c219000fe76a3ffbcaa846b689ba80 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 27 Jul 2022 12:22:56 -0400 Subject: [PATCH] block: change the blk_queue_bounce calling convention The double indirect bio leads to somewhat suboptimal code generation. Instead return the (original or split) bio, and make sure the request_queue arguments to the lower level helpers is passed after the bio to avoid constant reshuffling of the argument passing registers. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Reviewed-by: Johannes Thumshirn Link: https://lore.kernel.org/r/20220727162300.3089193-3-hch@lst.de Signed-off-by: Jens Axboe --- block/blk-mq.c | 2 +- block/blk.h | 10 ++++++---- block/bounce.c | 26 +++++++++++++------------- 3 files changed, 20 insertions(+), 18 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 790f55453f1b..7adba3eeba1c 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2815,7 +2815,7 @@ void blk_mq_submit_bio(struct bio *bio) unsigned int nr_segs = 1; blk_status_t ret; - blk_queue_bounce(q, &bio); + bio = blk_queue_bounce(bio, q); if (bio_may_exceed_limits(bio, q)) bio = __bio_split_to_limits(bio, q, &nr_segs); diff --git a/block/blk.h b/block/blk.h index 623be4c2e60c..f50c8fcded99 100644 --- a/block/blk.h +++ b/block/blk.h @@ -378,7 +378,7 @@ static inline void blk_throtl_bio_endio(struct bio *bio) { } static inline void blk_throtl_stat_add(struct request *rq, u64 time) { } #endif -void __blk_queue_bounce(struct request_queue *q, struct bio **bio); +struct bio *__blk_queue_bounce(struct bio *bio, struct request_queue *q); static inline bool blk_queue_may_bounce(struct request_queue *q) { @@ -387,10 +387,12 @@ static inline bool blk_queue_may_bounce(struct request_queue *q) max_low_pfn >= max_pfn; } -static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio) +static inline struct bio *blk_queue_bounce(struct bio *bio, + struct request_queue *q) { - if (unlikely(blk_queue_may_bounce(q) && bio_has_data(*bio))) - __blk_queue_bounce(q, bio); + if (unlikely(blk_queue_may_bounce(q) && bio_has_data(bio))) + return __blk_queue_bounce(bio, q); + return bio; } #ifdef CONFIG_BLK_CGROUP_IOLATENCY diff --git a/block/bounce.c b/block/bounce.c index c8f487af7be3..7cfcb242f9a1 100644 --- a/block/bounce.c +++ b/block/bounce.c @@ -199,24 +199,24 @@ err_put: return NULL; } -void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) +struct bio *__blk_queue_bounce(struct bio *bio_orig, struct request_queue *q) { struct bio *bio; - int rw = bio_data_dir(*bio_orig); + int rw = bio_data_dir(bio_orig); struct bio_vec *to, from; struct bvec_iter iter; unsigned i = 0, bytes = 0; bool bounce = false; int sectors; - bio_for_each_segment(from, *bio_orig, iter) { + bio_for_each_segment(from, bio_orig, iter) { if (i++ < BIO_MAX_VECS) bytes += from.bv_len; if (PageHighMem(from.bv_page)) bounce = true; } if (!bounce) - return; + return bio_orig; /* * Individual bvecs might not be logical block aligned. Round down @@ -225,13 +225,13 @@ void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) */ sectors = ALIGN_DOWN(bytes, queue_logical_block_size(q)) >> SECTOR_SHIFT; - if (sectors < bio_sectors(*bio_orig)) { - bio = bio_split(*bio_orig, sectors, GFP_NOIO, &bounce_bio_split); - bio_chain(bio, *bio_orig); - submit_bio_noacct(*bio_orig); - *bio_orig = bio; + if (sectors < bio_sectors(bio_orig)) { + bio = bio_split(bio_orig, sectors, GFP_NOIO, &bounce_bio_split); + bio_chain(bio, bio_orig); + submit_bio_noacct(bio_orig); + bio_orig = bio; } - bio = bounce_clone_bio(*bio_orig); + bio = bounce_clone_bio(bio_orig); /* * Bvec table can't be updated by bio_for_each_segment_all(), @@ -254,7 +254,7 @@ void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) to->bv_page = bounce_page; } - trace_block_bio_bounce(*bio_orig); + trace_block_bio_bounce(bio_orig); bio->bi_flags |= (1 << BIO_BOUNCED); @@ -263,6 +263,6 @@ void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) else bio->bi_end_io = bounce_end_io_write; - bio->bi_private = *bio_orig; - *bio_orig = bio; + bio->bi_private = bio_orig; + return bio; }