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block: change the blk_queue_bounce calling convention

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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 <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220727162300.3089193-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2022-07-27 12:22:56 -04:00 committed by Jens Axboe
parent 5a97806f7d
commit 51d798cdb5
3 changed files with 20 additions and 18 deletions
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2
block/blk-mq.c
View File

@ -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);

10
block/blk.h
View File

@ -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

26
block/bounce.c
View File

@ -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;
}