[RFC PATCH 17/22] bio: add bvec_length(), like iov_length()

[Dave Kleikamp <dave.kleikamp@oracle.com>]

From: Zach Brown <zab@zabbo.net>

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: Zach Brown <zab@zabbo.net>
---
 include/linux/bio.h |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 129a9c0..913087d 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -268,6 +268,14 @@ extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set
 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
 extern unsigned int bvec_nr_vecs(unsigned short idx);
 
+static inline ssize_t bvec_length(const struct bio_vec *bvec, unsigned long nr)
+{
+	ssize_t bytes = 0;
+	while (nr--)
+		bytes += (bvec++)->bv_len;
+	return bytes;
+}
+
 /*
  * bio_set is used to allow other portions of the IO system to
  * allocate their own private memory pools for bio and iovec structures.
-- 
1.7.9.2