[PATCH 01/60] block: bio: introduce bio_init_with_vec_table()

Some drivers often uses external bvec table, so introduce
this helper for this case. It is always safe to access the
bio->bi_io_vec in this way for this case.

After converting to this helper, it will becomes a bit easier
to evaluate the remaining direct access to bio->bi_io_vec,
so it can help to prepare for the following multipage bvec
support.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
 include/linux/bio.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 97cb48f03dc7..8634bd24984c 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h

@@ -664,6 +664,16 @@ static inline void bio_inc_remaining(struct bio *bio)
 	atomic_inc(&bio->__bi_remaining);
 }
 
+static inline void bio_init_with_vec_table(struct bio *bio,
+					   struct bio_vec *table,
+					   unsigned max_vecs)
+{
+	bio_init(bio);
+	bio->bi_io_vec = table;
+	bio->bi_max_vecs = max_vecs;
+}
+
+
 /*
  * bio_set is used to allow other portions of the IO system to
  * allocate their own private memory pools for bio and iovec structures.

-- 
2.7.4