This helper can be used to iterate each singlepage bvec
from one multipage bvec.
Signed-off-by: Ming Lei <ming....@redhat.com>
---
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
