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authorKent Overstreet <kmo@daterainc.com>2013-11-24 06:34:15 +0400
committerKent Overstreet <kmo@daterainc.com>2013-11-24 10:33:56 +0400
commit196d38bccfcfa32faed8c561868336fdfa0fe8e4 (patch)
tree9dee2bc174436072c9e90ffebbe71f47fde63aaf /include/linux
parente90abc8ec323c1fd2a25600097ef7ae1e91f39b0 (diff)
downloadlinux-196d38bccfcfa32faed8c561868336fdfa0fe8e4.tar.xz
block: Generic bio chaining
This adds a generic mechanism for chaining bio completions. This is going to be used for a bio_split() replacement, and it turns out to be very useful in a fair amount of driver code - a fair number of drivers were implementing this in their own roundabout ways, often painfully. Note that this means it's no longer to call bio_endio() more than once on the same bio! This can cause problems for drivers that save/restore bi_end_io. Arguably they shouldn't be saving/restoring bi_end_io at all - in all but the simplest cases they'd be better off just cloning the bio, and immutable biovecs is making bio cloning cheaper. But for now, we add a bio_endio_nodec() for these cases. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/bio.h2
-rw-r--r--include/linux/blk_types.h2
2 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 0c32a45a419c..64f5169c224b 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -356,6 +356,7 @@ static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
}
extern void bio_endio(struct bio *, int);
+extern void bio_endio_nodec(struct bio *, int);
struct request_queue;
extern int bio_phys_segments(struct request_queue *, struct bio *);
@@ -364,6 +365,7 @@ extern void bio_advance(struct bio *, unsigned);
extern void bio_init(struct bio *);
extern void bio_reset(struct bio *);
+void bio_chain(struct bio *, struct bio *);
extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d369f8f6af79..bbc3a6c88fce 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -65,6 +65,8 @@ struct bio {
unsigned int bi_seg_front_size;
unsigned int bi_seg_back_size;
+ atomic_t bi_remaining;
+
bio_end_io_t *bi_end_io;
void *bi_private;