From 0ef5a50c1658d4d96a44f145bcb92ff3310c75b1 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 5 May 2016 11:54:22 -0400 Subject: [PATCH] block: make bio_inc_remaining() interface accessible again Commit 326e1dbb57 ("block: remove management of bi_remaining when restoring original bi_end_io") made bio_inc_remaining() private to bio.c because the only use-case that made sense was confined to the bio_chain() interface. Since that time DM thinp went on to use bio_chain() in its relatively complex implementation of async discard support. That implementation, even when converted over to use the new async __blkdev_issue_discard() interface, depends on deferred completion of the original discard bio -- which is most appropriately implemented using bio_inc_remaining(). DM thinp foolishly duplicated bio_inc_remaining(), local to dm-thin.c as __bio_inc_remaining(), so re-exporting bio_inc_remaining() allows us to put an end to that foolishness. All said, bio_inc_remaining() should really only be used in conjunction with bio_chain(). It isn't intended for generic bio reference counting. Signed-off-by: Mike Snitzer Acked-by: Joe Thornber Signed-off-by: Jens Axboe --- block/bio.c | 11 ----------- include/linux/bio.h | 11 +++++++++++ 2 files changed, 11 insertions(+), 11 deletions(-) diff --git a/block/bio.c b/block/bio.c index 807d25e466ec..0e4aa42bc30d 100644 --- a/block/bio.c +++ b/block/bio.c @@ -311,17 +311,6 @@ static void bio_chain_endio(struct bio *bio) bio_endio(__bio_chain_endio(bio)); } -/* - * Increment chain count for the bio. Make sure the CHAIN flag update - * is visible before the raised count. - */ -static inline void bio_inc_remaining(struct bio *bio) -{ - bio_set_flag(bio, BIO_CHAIN); - smp_mb__before_atomic(); - atomic_inc(&bio->__bi_remaining); -} - /** * bio_chain - chain bio completions * @bio: the target bio diff --git a/include/linux/bio.h b/include/linux/bio.h index 6b7481f62218..9faebf7f9a33 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -702,6 +702,17 @@ static inline struct bio *bio_list_get(struct bio_list *bl) return bio; } +/* + * Increment chain count for the bio. Make sure the CHAIN flag update + * is visible before the raised count. + */ +static inline void bio_inc_remaining(struct bio *bio) +{ + bio_set_flag(bio, BIO_CHAIN); + smp_mb__before_atomic(); + atomic_inc(&bio->__bi_remaining); +} + /* * bio_set is used to allow other portions of the IO system to * allocate their own private memory pools for bio and iovec structures. -- 2.20.1