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 <snitzer@xxxxxxxxxx>
Acked-by: Joe Thornber <ejt@xxxxxxxxxx>
---
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 807d25e..0e4aa42 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 6b7481f..9faebf7 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -703,6 +703,17 @@ static inline struct bio *bio_list_get(struct bio_list *bl)
}
/*
+ * 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.
* These memory pools in turn all allocate from the bio_slab
--
2.6.4 (Apple Git-63)
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