[PATCH 44/60] block: introduce bvec_for_each_sp_bvec()

[Ming Lei]

This helper can be used to iterate each singlepage bvec
from one multipage bvec.

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

diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index e12ce6bd63d7..510d1d2d79f1 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -191,4 +191,14 @@ static inline void bvec_iter_advance_mp(const struct bio_vec *bv,
 	.bi_bvec_done	= 0,						\
 }
 
+#define __bvec_for_each_sp_bvec(sp_bvl, mp_bvec, iter, start)		\
+	for (iter = start,						\
+	     (iter).bi_size = (mp_bvec)->bv_len;			\
+	     (iter).bi_size &&						\
+		((sp_bvl = bvec_iter_bvec((mp_bvec), (iter))), 1);	\
+	     bvec_iter_advance((mp_bvec), &(iter), (sp_bvl).bv_len))
+
+#define bvec_for_each_sp_bvec(sp_bvl, mp_bvec, iter)			\
+	__bvec_for_each_sp_bvec(sp_bvl, mp_bvec, iter, BVEC_ITER_ALL_INIT)
+
 #endif /* __LINUX_BVEC_ITER_H */
-- 
2.7.4