[PATCH v3 26/49] 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 
---
 include/linux/bvec.h | 14 ++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index c1ec0945451a..23d3abdf057c 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -224,4 +224,18 @@ static inline bool bvec_iter_advance_mp(const struct 
bio_vec *bv,
.bi_bvec_done   = 0,\
 }
 
+/*
+ * This helper iterates over the multipage bvec of @mp_bvec and
+ * returns each singlepage bvec via @sp_bvl.
+ */
+#define __bvec_for_each_sp_bvec(sp_bvl, mp_bvec, iter, start)  \
+   for (iter = start,  \
+(iter).bi_size = (mp_bvec)->bv_len  - (iter).bi_bvec_done; \
+(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 */
-- 
2.9.4

[PATCH v3 26/49] 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 
---
 include/linux/bvec.h | 14 ++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index c1ec0945451a..23d3abdf057c 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -224,4 +224,18 @@ static inline bool bvec_iter_advance_mp(const struct 
bio_vec *bv,
.bi_bvec_done   = 0,\
 }
 
+/*
+ * This helper iterates over the multipage bvec of @mp_bvec and
+ * returns each singlepage bvec via @sp_bvl.
+ */
+#define __bvec_for_each_sp_bvec(sp_bvl, mp_bvec, iter, start)  \
+   for (iter = start,  \
+(iter).bi_size = (mp_bvec)->bv_len  - (iter).bi_bvec_done; \
+(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 */
-- 
2.9.4