[PATCH 2/4] block: add for_each_mp_bvec()

[Ming Lei <ming.lei@redhat.com>]

Add helper of for_each_mp_bvec() for io_uring to import fixed kernel
buffer.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 include/linux/bvec.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index ba8f52d48b94..204b22a99c4b 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -184,6 +184,12 @@ static inline void bvec_iter_advance_single(const struct bio_vec *bv,
 		((bvl = bvec_iter_bvec((bio_vec), (iter))), 1);	\
 	     bvec_iter_advance_single((bio_vec), &(iter), (bvl).bv_len))
 
+#define for_each_mp_bvec(bvl, bio_vec, iter, start)			\
+	for (iter = (start);						\
+	     (iter).bi_size &&						\
+		((bvl = mp_bvec_iter_bvec((bio_vec), (iter))), 1);	\
+	     bvec_iter_advance_single((bio_vec), &(iter), (bvl).bv_len))
+
 /* for iterating one bio from start to end */
 #define BVEC_ITER_ALL_INIT (struct bvec_iter)				\
 {									\
-- 
2.47.0